My 20hp 1988 Johnson Upgraded To 35hp

[@AmericanFreedomPatriot]

Great video revealing the simple mod to the OMC 521cc engines. It was a known thing that OMC used common engine blocks for various HP motors. That same "521cc" twin in your Johnson (and the same Evinrude models) was used in the 20, 25, & 30 HP motors after 1986 when the horsepower was measured at the "prop shaft" the 35 hp of 1979 to 1983 had its 35 horsepower measured at the "crank shaft" (which gave 30 hp at the prop) as my brother worked for OMC, he revealed that OMC then could price a 35/30 HP motor nearly a thousand dollars over the 20 HP, but the cost of creating the 30/35 was less than 50 bucks at the factory over the 20hp! Also they offered a 28HP commercial version, that had lower gearing of a 30HP, but twice the prop-shaft torque, to push heavy fishing boats. ( and the rare 18 HP Outboard Jet-drive. One thing you forgot, is the reed-valve stops. The 35/30HP had higher stops, which allowed the reed plates to open a little more. Switch those out and gain another couple mph. Back then these 521's were the torque king of the small outboards.

[@sharpfork]

Thanks for the awesome info! I just picked up a 1988 Evinrude 28HP SPL and have been searching for info and potential upgrades/ mods. I'd love to know more about the lower gearing of the 30 HP and what that would mean on my 1983 17' bass tracker.

[@timothyclingerman5430]

Thanks "NAVY", I am an ARMY Vet, but hey, we are all in this togather and I thank you for your service. I agree, the "521cc" is one of the most versitile outboards made. It can be set up as a 20HP, Smaller throat, Intake porting and Carb, all the way to 35HP (pre "86"). Thanks!

[@AmericanFreedomPatriot]

@@timothyclingerman5430 The same motors were used on our smaller RIBs for many years.

[@s.v.gadder1443]

Reeds are the same part number.

[@danh8751]

So a 30 horse johnson can only be upgraded to a 35 horse johnson? Bigger carburetor and intake? Can i add electic start?

[@randyroth383]

Thanks John for the tec talk.👍more videos mybe about props n reeds im sure you get views 🙋

[@kylejorgensen1412]

I've done this modification to several motors and the carburetor is the biggest improvement, the intake manifold isn't really noticeable but I'm sure it helps some but not worth the effort if it's not restricted like on the 20. I've also taken a 20 intake and drilled it bigger for the larger carburetor. Also the early 35s have smaller combustion chambers than the later 25s something I just noticed this week while doing a head gasket on both and had them side by side. FYI the 1984 25hp has the large 35 carburetor don't ask me why but I have two of them and both had them and when you look it up on the parts diagram it shows that's what it came with

[@jbow27]

My dad bought a1984 25 johnson in 1989. It is in the family still and running strong. I recently purchased a 1984 evinrude 9.9 in nearly mint condition. Long live OMC.

[@iBackshift]

Miami Vice buddy... That boat ripped, woo! ! !

[@robertmckinnon7245]

Great video, I have a 25hp Suzuki outboard, did a simple carb linkage modification, cost nothing to do and the results were incredible, the boat went from going 21mph to 31mph,and yes,its an adrenaline rush..if any one watching and has a Suzuki motor, its easily done,only takes a few minutes, all you need is a bench grinder, or a hand grinder.

[@christiangarstad-berg4490]

Dose that count with a 75 hp DT Too?, or were you just talking about the 25

[@robertmckinnon7245]

@@christiangarstad-berg4490 I'm not sure on 75 Suzuki, the 25 hp was governed, if you open your throttle all the way open,without it running, look inside the carbs and see if the butterfly's are all the open,if they are not,then you have room for adjustment or maybe even the linkage modification..

[@neramuli8849]

Can you explain me,if a can make this to mercury 25 hp 1990?

[@RandyBraa]

Glad to hear your Johnson's OK

[@zzz7zzz9]

Hope all our Johnson's are doing ok.

[@afaketwo]

Picks up speed really fast. I test at a fresh water lake and noticed the current in the ocean can make your boat fast or over work the outboard trying to .

[@kiheirc3195]

Interesting work thanks for video

[@jacklowe3788]

Good Stuff! Thanks for the video!

[@I_am_archie]

I've got a 1986 evenrude 25 it would be great to get 10 more HP. That sounds just like mine. I'm using it in the morning to catch some Utah Lakers.

[@Motown21203]

Nice you ever do it, I just got me a 20hp around the same year and is evinrude and I want to add these mods

[@judechopper]

Screams good work

[@252outdoorsman7]

What prop size were you using. Great video

[@blackmouthcur6097]

Most people don’t realize that the manufacture only makes a few different power heads and that they de tune units to slow them down! 4-6 same on most 8-15 same on most 20-35 same on most Now this point on different manufacturers change the power heads at different levels, but it’s a simple search on their sites to make quick comparison to say 60-85 is same just as 90-120 is same on some. You just need to look.

[@jon9879]

That is awesome.

[@bradd3582]

That’s awesome!!!!!

[@richardluce775]

They also “tuned” the exhaust a bit with a separator plate that directed the gases instead of the stamped flat plate

[@donniegray2288]

I found a 79 model 35hp i thought about getting to do this to my 84 jhonson 25hp i think it should work it looks the same but won't know until i tear into it but i hope it is it's a 521cc too.Ive also got a 93 25 and it's close to the same also i may try to convert both of them in time.Yhsnks for the video man and you did well.

[@unsaltedlife5998]

Very nice 👍

[@DougsMessyGarage]

Interesting upgrade. Did you change the prop as part of this upgrade? A bit coarser prop would likely drop the RPMs a little and put more the the energy into the water.

[@johns.6570]

I was running a 10x13,, as stock, and same prop with upgrade I’d wouldn’t run anything smaller than that it’ll probably over rev

[@johns.6570]

I’m was using a 10x13, tried a 10x15 though , reduced holeshot but gained 1 mph on the top end , I think I’m really close to where I should be

[@DougsMessyGarage]

@@johns.6570 I am far from an expert but it sounds to me like you are in the ballpark

[@mr.robert2507]

Great video. I have a 20 HP and looking for someone who can do the upgrade. Thanks

[@zlix_2045]

I got a 83 20hp, what parts do i need to upgrade to 30/35? And how do i change the timing up ? Thanks in Advance John S

[@redorrick427]

how do you advance the final timming?

[@douglasthompson2740]

Several models of the Johnrudes were that way and some other makes did the same of that era. Don't know about modern models but I would wager that changing the computer programming might be possible to the same end on some similar models?

[@johns.6570]

What are you talking about computer programming ? thers no computers in these things

[@brodieblomberg5625]

I just bought the exact same engine, 1988 johnson 20 that was upgraded to a 35. it kept having probelms and barely ran so i took it to get fixed, should get it back soon

[@johns.6570]

Well that was a mistake, If you don’t know this stuff then it’s better not to hand it off to a dealer, I know a guy who handed his motor off to a dealer didn’t get his motor back for 2 months , charged him 1000$ to do all kinds of unnecessary stuff, and didn’t fix the issue, I found the issue in less than 5 minutes, some dealers are not stupid they just wanna make cash and drain your pocket.

[@tonylynn191]

@@johns.6570what’s was the issue timing or fuel adjustment??

[@fink4569]

Can you show the timing set up?

[@randyroth383]

Subbed 👍

[@alnbaba]

Just ordered a 35hp intake from Crowley marine all ready have the carb, intake was only $20.

[@johns.6570]

Bonus

[@ls2005019227]

Just found your channel [subscribed!] Very interested in this kind of performance improvements- Are the carb/intake swaps limited to having the same basic block (which was used for multiple HP motors)? Is there a formula/guideline for the limit of swapping bigger carbs to an originally smaller factory block? Thanks!

[@johns.6570]

Those blocks are basically the same from 1978 to up and past the 2000’s, most of it is a carb and intake swapping, although Im working with a 1976 35hp points motor, it has much bigger exhaust ports, and the gearing is also different on the older motor ,results I think will differ, so It should be ready for water in about a week, if the motor is any good.The motor I should was using pretty much later model parts and the early carburetor,and intake, and the gearcase is gear different so let’s see, I had old school 35hp last summer with the smaller exhaust ports and did 36mph, so let’s see, if the motor I’m working on is any good then I’ll definitely do a video on it.

[@nathanwest6599]

Hey johnS I could use your help, with the timing on my conversion

[@soulfly945]

After watching your video, I plan on swapping out the carbs, reed plates, and intake on my 1984 25hp Evinrude with those from a 1982 Evinrude 35HP, but is the bypass plate necessary to swap out as well? Im not the most knowledgeable outboard motor guy, but I do enjoy tinkering and working on my own cars, motors, etc when given the chance and hopefully these mods will help save me some money from having to buy a larger outboard for awhile for my boat to get the performance I'm looking for.

[@johns.6570]

Depends if yu have the fitting, on it, It runs from the intake to bypass cover, and yu don’t need to change the reed plate they are the same

[@CayneWatt]

did you ever end up swapping carbs? i have a 84 evinrude 25hp as well.

[@nellawell4976]

Like to see that stainless prop on it now.

[@johns.6570]

I sold the motor 2 days after I did the video, I built another one this winter, 1993 Johnson 25 upgraded to 35 hp, that’s the one with front shifter, I’ll be showing that one as a follow up, doing the video when the weather gets nice and we get out of lockdown.

[@RDM1969]

Hi John, great video! I’ve got a 1982 20hp with non-thru hub exhaust, what max hp upgrade would you say is possible to mine?

[@johns.6570]

Well I’ve heard of others that have done that upgrade, but I have no idea of the results

[@bryanromeo7949]

Could this be done to a 2003 Johnson 25hp two stroke? Great video and details to the process 👏

[@johns.6570]

That one has front shifter you would have to remove that for a side shifter, best way to do this with the use of your front shifter is to go to 30hp , with a 30hp carb and intake setup

[@mathieujvideos4403]

hello I have a quick question! why exactly does the 35 HP carb not work with the front shifter?

[@led8541]

That is Great

[@bulletman124XXL]

Excellent video thanks for sharing!

[@randyroth383]

My 25 johnson year 94 is good to go it had small hole in the carb throat bore.my intake is the same as 35 . i put a 35 carb on it an yes it's a scream demon. I have on hand to 2 defrent tipe of reeds

[@johns.6570]

Way to go, dude , I may try that setup too and see what happens

[@randyroth383]

Hay john i took the carb off of a 20 horse rude it had the bigger throatcarb on it but the factory made that year the exhaust is a horn not thru the prop an it had 2 piece lower unit thats why it a 20 not a 35. It's a mid 80s i guess. Florida🙋

[@johns.6570]

@@randyroth383 Somebody could of modded it, before you got to it, I’m not a OMC engineer, but I found some factory engineers are book smart not hand smart anyway the setup I mean the actual 35hp parts works better than stock 30hp parts,better fuel economy and way better low end torque and grunt out of the hole , matching your prop to your boat makes a big difference, the last one I tested 10x15 aluminum made 36mph on my boat,I always recommend tuning the prop to my customers boat but they usually walk away thinking I want to gouge them for more $$$$, it makes a difference anyway you want to slice the pie, it’s all about dynamics, and water conditions matter as well,I can get a bit more top end speed with slight chop on the lake,then compared to flat water, hope this helps.

[@johns.6570]

The carb may bolt up to the 94 motor, but they are absolutely different.

[@mg.5246]

Hi John! great job ! Tel me please, the reed plate is the same on 25hp 30hp 35hp?

[@johns.6570]

It’s the same as 1980 35hp, which is no different from the newer years same pedals same size,,20-35hp, I tested this upgraded motor against a 1984 35hp, same top speed no difference.

[@radman6350]

Best tiller ever made

[@johns.6570]

@@radman6350 haha lol

[@johns.6570]

@@radman6350 ya there good

[@timothyclingerman5430]

The same, you do need to monitor WOT RPM after upgrade.... Be sure you are running approx. 5500 RPM @ WOT, if higher, you may have to change from STD. 13(pitch) to a 15(pitch) as to not over REV motor.

[@randyroth383]

Just asking👍what Reed's are you using diming shape or tear drop looking on the plate. 🚣

[@johns.6570]

Stock factory 1989 reeds 20hp

[@Dudlushka]

I'd like to put a thermometer to my '72 20hp Johnson (I think the cooling system is similar). Could you please recommend, where should I drill the hole/thread to the sensor (1/8 NPT threaded Temp Sensor)

[@Dudlushka]

(I wanted to send you a private messege, 'cause you look like an expert in this topic , sorry that I posted it here)

[@johns.6570]

I have no idea what your talking about….

[@eugenezhulik2117]

Hello from Finland. What is the name of this bracket on the transom that the motor is mounted on? Where to buy one?

[@johns.6570]

It’s called a jackplate, I purchased on ebay since I purchased there has been significant design upgrades in the industry, such as a hand crank to raise and lower the motor , mine has a bolted fixed adjustment, it’s adjustable but not as nice as using a hand crank.

[@owenaquilina5001]

Dear what is the purpose of the keeper underneath the linkage gearbox joint. I lost the nylon tapered keeper can I replace it with a small O ring please so the linkage nut will not slip off? Thanks in advance, very informative video

[@johns.6570]

If yu don’t have that it won’t lock the 2 rods together

[@owenaquilina5001]

@@johns.6570 Can it be the reason why the motor is running as if on high rev and waterpump not function even though was just replaced? Thanks in advance for your assistance

[@johns.6570]

@@owenaquilina5001 I can’t see what you’ve done obviously something in done wrong, I can’t evaluate it just from your words sorry.

[@johns.6570]

@@owenaquilina5001 I don’t know why the motor is running high rev, and yu probably did not line up the water tube properly that’s why no water pump, yu cannot just use a o-ring , yu need to use what was made to do the job..

[@owenaquilina5001]

@@johns.6570 iI know i need to purchase a tapered keeper for the gearbox joint, do you have an idea from your I can purchase within Europe please? Also if the gasket has been torn while re-dimsantling and ckecking from one side can it be reused? Thanks

[@michaelcolicchio7172]

Just bought a boat with evinrude 25 hp 1994 E25TEERC, do you happen to know if I am able to do a 35 hp swap and what all I would need ?

[@johns.6570]

Can be done yu need a 35hp carb primer style 1984-1988

[@johnchaos78]

Is it common in US when you talk speed at water it is miles per hour? In europe we use always knots at water. I'm from Finland.

[@johns.6570]

I’m from a time when mph was the way in Canada before the metric conversion, on the water most people talk mph, and that’s the speed measurements I was talking in 34mph tops, approximately 54.4 mph, I got a early 76 35hp this past spring and got 34.7;mph in 6in choppy water ,getting air makes a difference.

[@frankolbrot2923]

Is there a modification that can be done to a 1992 evinrude 28 spl pushes a 16’ pontoon. What pitch propeller would you recommend for a pontoon. Seems they are 13 spline 9 1/4x9 , 9 1/4x10 , 9 1/4x11 and 9 1/4 x 12 available for this motor.

[@johns.6570]

Wow that motor uses old style gearcase, and your pushing a lot of weight, I’d start with the smallest pitch prop and go from there,you can buy a portable tach. for under 20$, ask a dealer what the max rpm is for that motor tach it and try to match by changing props,I had a big Bayliner 3500lbs 22ft that was propped wrong made 7 mph wide open, when I eventually propped it right that’s going from a 13.75x15 to a 14x9 the boat made 19mph with the right prop and max rated rpm for the engine, a. 12mph difference with just a prop change.

[@frankolbrot2923]

@@johns.6570 thank you. I was thinking I was going to mess with the prop first. We just cruise with our pontoon so it’s not for tubing or skiing. But we also would like to get the most out of what we have. The pontoon is actually light. With motor and gear ( no people) it weighs about 2000 lbs however being a pontoon it’s like pushing a sheet of plywood on the water. Thanks again.

[@wish2fish37]

Why change bypass cover on 35 conversion.?I did a 20 to 30 mid 80’s.

[@johns.6570]

Late 70’s bypass cover does not match early 80’s and up,and there’s a fuel or vacuum line that runs from the intake manifold to the bypass cover that is required, not like yur 20-30hp upgrade ,earlier 35hp carb and intake requires this line as described in the video.

[@brt-jn7kg]

I have a 1992 Evinrude 25 horsepower that I put a 35 horsepower carburetor on and I'm having a running miss you. I cannot keep the engine I believe as long as I am advancing and retarding the throttle body engine will run but will not idle I think perhaps I'm having a jetting issue

[@johns.6570]

Sorry I can’t be there to help you…

[@Mascotal]

So, you don't think engine displacement has anything to do with horse power? Maybe just change the sticker on the engine cover would do the same thing.

[@johns.6570]

20-35 hp are all 512cc, it makes sense, a cost effective way of building 4 engine horsepower range with modifying very little.

[@craftyha]

Where you get the parts? New? Carb and manifold.

[@johns.6570]

I have the. On hand here

[@kentyler966]

Any idea how many RPMs you are spinning, sounds like she is spinning pretty high?

[@johns.6570]

no idea no tach,

[@johns.6570]

you wont blow it up the earlier 35, had poorer quality bearings, later model bearings are way better qualit Im talking about late 80's bearings, thats when OMC introduced 100:1 oil ratios, they had to be better to accomodate less oiling

[@johns.6570]

and yes its so much fun, its a real adrenaline rush

[@nachospeakstoday]

Hi John. I own a '86 90hp V4 evinrude. Does this mod works to upgrade it to 115 or 140 hp? I've heard that they used the same block for different motors. Greetings from Argentina.

[@johns.6570]

I don’t know anything those motors

[@amychartraw1]

There are some a good number of mods with the V4 omc motors, and certain parts that are sought after because of this (carbs and intake from the odd 135 hp). However, and it's a big However, it's not nearly as simple as the mod made for this video. The v4 came in many very different configurations, and also much more hp was allowed or muffled as it were by control of exhaust. So while what you ask is very likely possible, it would require a ton of research and learning for anyone not intimately familiar with the omc v4 family.

[@ct1762]

very simple: you can't without porting and exhaust work. big difference not the same blocks lol. the ports are much larger on the 110-140hp motors (same on XP100 as well). and they had the bubble exhaust, which requires major machining to match. you also need the tighter heads. much easier to find a 110-140hp powerhead or whole motor. it would run like CRAP if you just gave it the 1 5/16'' carbs.

[@dionwilson4214]

Where r u sitting at lol! Didn’t seem like a normal driving position

[@johns.6570]

I’m sitting on the floor too fast to sit on the bench seat I’ll fall off the boat for sure

[@danielhaglund244]

What size propeller are you using to get 34 mph?

[@johns.6570]

10x13

[@billscreations1999]

That thing is stupid fast

[@johns.6570]

Ya but it’s so much fun

[@tintdr]

What size prop are you running?

[@johns.6570]

10x13 turning point

[@bobsugrue2703]

I have a 1976 Johnson 6hp is there anything i can do to it to make more power ?

[@johns.6570]

try a 8hp carb I think the motors are the same

[@timothyclingerman5430]

@@johns.6570 Hey Bob, you may also have to change the fuel line size from 1/8 Id to 1/4 id for sufficient fuel flow.

[@s.v.gadder1443]

Fuel pump is also different

[@johns.6570]

Same fuel as most earlier models , just that we didn’t use the 3/8 to 1/8 adapter

[@Puukko79]

Hahaha awesome

[@nathanwest6599]

Ok so, I've got 2 1980 35hp evinrudes. I'm using all the parts from the 2 to upgrade my 1985 20hp. What ever is left I'm more than willing to part with .

[@timothyclingerman5430]

Hi Nathan, I know there must be reason, but why not combine parts from both 35's to make one good 35HP.?

[@nathanwest6599]

@@timothyclingerman5430 honestly unsure if condition of either 35, just good donor parts. Both are long shaft as well as non tiller controls.

[@michaelcolicchio7172]

Would be interested in the carb and manifold , lmk

[@lruityfoops2792]

hey is this possible with a motocycle too?

[@johns.6570]

Anything is possible

[@alabamaoutdoors4468]

Had a 1985 25 hp johnson pushed a 1636 aluminum with passenger and heavy aluminum cooler livewell. 35 mph ! Idk ?

[@thomassmith9305]

I just bought that exact setup. Hope to have it on the water next weekend. Nothing special done to the motor to get that speed?

[@godwincena3421]

What's the size of the carbourater?

[@johns.6570]

What size ? are you asking about cfm gosh I have no clue., but other than that, it’s about r4 inches long, 3 inches wide, and about 3 inches high.hope this helps….

[@Rangerrolltide]

Hey John! I can't explain hoe happy I was to discover this video. I have been researching for hours a day for a few days now trying to figure out how to do this upgrade to my 1993 johnson 20hp (J20CRLETS). I have posted on Facebook and in forums trying to learn what I can. Is there any way I could get some help figuring out what carb and intake I need for my 20hp? I will donate to the channel or help in any way I can. I'm just really trying to figure this out and just can't quite figure it. If there is any way I could email you or get a hold of you some how that would be amazing! If you have any parts I need I would love to buy them from you as well!! Any help would be greatly appreciated! Thank you again for the video too! I can post my email in the comments if that would help!

[@johns.6570]

Well just message me 1992 has different architecture than 1988 but it’s not impossible

[@Rangerrolltide]

@@johns.6570 I'm honestly not really sure how to message anyone on KZbin? What am I looking for in a matching carb?

[@Rangerrolltide]

John, Is there a way to get in contact with you? I do not see a way to message you separately?

[@Dudlushka]

Is this mod possible in Johnson/Evinrude motors made in the 90s?

[@johns.6570]

Indirectly yes 90’s motors have the shifter in the front, shifter rod goes through the hole the where the choke lever is located, yu can go 30hp on those motors, I have a few 30hp kits here, in Canada, but if yu want to absolutely use the 35hp carb and intake you’ll have to remove the front shifter and replace it with a side shifter.then yu can make use of the shifter rod hole for the manual choke system.

[@Dudlushka]

@@johns.6570 thx for your kind response! In this year the legal h.p. limit has been risen to 20hp (from 10) in our country. (till these days I used a pumped 9.9 evinrude) ...So Im hunting for these kind of OMs...

[@Dudlushka]

...and I saw an evinrude 20/25 that looks 90s (but im not sure) It has cdi ignition, and the whole body is gray. the sticker style looks 90s to me

[@johns.6570]

Could be early 2000’s

[@kpd3308]

Can anybody explain what the bypass plate changeout is for?

[@johns.6570]

There’s a line running from the intake to a fitting on the bypass cover, usually found only on remote motors, that block was converted over from a remote motor, Im thinking it’s for faster cold starts it’s a assumption only, I did build a engine without changing the bypass cover and I blocked off the fitting on the intake and it seemed to work just as well as any other, I’m trying something new this spring using a old 1976 35hp motor with big exhaust porting and a primer setup, and I’m blocking off the bypass cover fitting,let’s see what happens.well most of the tiller motors do not use the bypass cover with the extra fitting.

[@matth3637]

Can I do this to a 30 hp johnson?

[@johns.6570]

Sure but not really too much advantage, I’m up 2 mph from a 30hp, 20-35 is huge though.

[@dawsoncox2453]

Hey man I have a 88 evinrude 25 hp and I’ve been trying to do my research but I don’t know what years of 35 hp carbs I can use or where I can find them. Any help would be much appreciated.

[@johns.6570]

Well that’s a unique problem you need a primer 35hp carb, from 1984 to 1988 35 very rare,I have ONE of these carbs that’s been rebuilt, it could be for sale ,you may , I said may have to change the intake as well, because real 25hp intakes are different then 30/35. Intakes yes the bore and the runner is slightly smaller on the 25hp intake but you may get lucky as OMC used 30/35 intakes on their 25hp’s you have to google the part no on the intake to identify it,hope this helps.

[@johns.6570]

But you can also do whatI I did using old school parts 1980ish 35hp parts

[@dawsoncox2453]

John S. Hey thank you for replying so fast! So what you’re saying is I have to use that year frame of carb? Or can I put one with an electric choke on there? I have only been able to find a 83 model. And if I have to how much would the carb you have cost me?

[@johns.6570]

@@dawsoncox2453 are u in Canada? There’s all different ways of getting the right outcome depends on your circumstances

[@dawsoncox2453]

John S. No, I live in the US. And what your saying is I can make the 1983 carb work?

[@todd6743]

I have a 1996 evinrude 20 horse power I have been looking at upgrading. What would be needed to get it to 35 horse power?

[@johns.6570]

As always carb and intake

[@johns.6570]

I have 30hp kits here a lot easier than going 35hp on that motor

[@todd6743]

@@johns.6570 Do you sell a 30HP kit? Would love to get the parts needed.

[@johns.6570]

@@todd6743 yes

[@todd6743]

@@johns.6570 Awesome, how can I purchase/how can I better contact you?

[@MIKE-mg5ks]

I HAVE A1986 28SPL, WOULD I NEED TO CHANGE THE BYPASS PLATE?

[@johns.6570]

Depends which carb and intake setup your using, old school carb has a line between intake and bypass cover, thers a reason it’s there

[@MIKE-mg5ks]

@@johns.6570 I WAS THINKING OF CARB MANFOLD FROM A 35HP

[@johns.6570]

@@MIKE-mg5ks ya but there’s 2 versions choke type and primer type

[@MIKE-mg5ks]

@@johns.6570 I HAVE THE PRIMER SET UP NOW AN PLAN ON A CARB THAT WAY AS WELL

[@johns.6570]

@@MIKE-mg5ks depending on the year yu may still have to use the bypass cover important thing is, you need to know whether or not your intake requires that bypass cover line

[@alekthefisherman5676]

What’s the difference between the 30 and the 35? Any idea? Thanks.

[@johns.6570]

Carburation and timing

[@m.n.70]

So I can turn my 30 to a 35 with just a carb???

[@johns.6570]

Carb and Intake , and timing advance, I sell the parts to do this.

[@alekthefisherman5676]

@@johns.6570 How much RPM do I need to increase in order for me to meet the 35 hp spect? What do I need to change in the carburetor? Is it the hi-speed jet, if so anybody know what size the 35 hp jet is? Thanks.

[@johns.6570]

Replace the carb and intake what year is it, it’s not a huge performance increase, 30 to 35hp made a 3 mph increase in speed on my boat.

[@jesusmendez54]

I have a 50 hp Johnson and it just those 10 mpg😢

[@johns.6570]

Ok your lucky great fuel economy

[@midgetmayo]

Hey , I've recently came across your ads on Kijiji .. I've been looking into these motors for a few months now, but my near future goal is to either find a 35 horse motor for the right price , or get a 20 and do the upgrades . Thanks for the video and sharing the info to do the upgrading .. I own a 1994 8 horsepower Evinrude, and I'm currently borrowing a 1982 15 horse Evinrude and it's still not enough. I'd be willing to trade the 8hp and cash for the right motor.. that thing looks fassst .. 35mph lol I have a 14' mirro craft so I don't think I'll be as fast as the inflateable lol

[@billythekid5196]

A 25 on 14 mirror craft is plenty I have one with jusvme an gear and deck does 30 mph

[@midgetmayo]

@@billythekid5196 I guess we will see.. I know that I wasn't satisfied with a really healthy 15hp ..

[@1polaris800]

Just got my hands on a 1977 35 hp, can i use this to convert my 1990 25 hp to a 35? They seem to be pretty much the same, can anyone confirm it for me? The 35 is a choke carb, and the 25 is a primer carb. Help is appreciated.

[@johns.6570]

If your shifter is in the front it technically it won’t work, because u need the hole where your shifter goes for the choke knob, thers another way to do it, that of which I haven’t tested, if your using the late 70’s intake your going to have to also use a bypass cover from a early 80’s motor, yu can’t use the bypass cover from the 1977 35hp motor it’s different from what you need to do it

[@1polaris800]

@@johns.6570 Oh, that's too bad if it doesn't fit. I thought they looked so similar. But the shifter is on the same place on both motors

[@1polaris800]

@@johns.6570 Thank you so much for answering, appreciate it.

[@johns.6570]

@@1polaris800I’m assuming your shifter is on the front I’m sure 1990 has it there, the shifter rod is in the lower cowl,and that rod goes through the hole that the choke lever uses , if yur shifter is on the side then your good to go, it that bypas cover from the 1977,is different from the one needed on the newer blocks, older late 70’s blocks were different from the 90’s blocks, and the only bypas cover that works is early 80’s choke carb models.

[@1polaris800]

@@johns.6570 The shifter is on the side on both engines, the choke and the primer is on the same spot like you describe in your video. Is there any way to modify the 25 hp bypass cover to match a 35 hp? If it is for any help, I live in Norway and have the european version of the engine.

[@don-magiclivescope-juan8752]

Hello love your video I have a 9.5 any info on speeding it up a little help please thanks alot

[@johns.6570]

Ther really isn’t anything yu can do with that to make it go any faster

[@myronclement3238]

@@johns.6570 Very informative video thanks for making it. I am trying to convert a 1999 25 johnson to a 30/35hp. I Have 1985 30hp carburetor. I gather that my current intake has the right carb to intake hole diameter but it wouldn't have the same depth/cubic inch capacity that a 30/35hp intake manifold would have correct? Another question is what is the reason for changing the bypass cover? Thanks for any help!

[@johns.6570]

Well yu should check the part no on the intake, thers a 1/8 of a inch difference between the 25 and 30 hp intakes, although OMC did also use

[@johns.6570]

Just continued, OMC did use the same intake for the 30hp,you won’t have to swap out the bypass cover on your motor.

[@myronclement3238]

@@johns.6570 331518 is the casting number on my 1999 25hp intake. 0396790 is the intake part number for engines with "C or N" suffix. My engine is model #J25ELEEN. 0396788 is the other intake part number for engines with "D" suffix. My engine model number ends with an "N". So I assume I currently have the right intake for the 30hp. But not the 35. Thanks for the reply!

[@spod11]

this guy is smarter than a brain surgion

[@Sleeplesstorm]

Are you interested in selling this motor ?

[@johns.6570]

Do u live in Ontario Canada, that’s a possibility.

[@MaliciousSRT]

@@johns.6570 I do and need a good running 2-stroke 15, anything in stock? lol

[@johns.6570]

@@MaliciousSRT are u close to Lindsay,Ontario?

[@MaliciousSRT]

@@johns.6570 Yes

[@johns.6570]

@@MaliciousSRT well I have a 1984, 9.9 , it has a 15hp power head with a 15hp carb there that might be of interest

[@Hunter_s_morrison]

Dumb question what are the steps to starting the motor

[@johns.6570]

Prime it choke it, hit the starter button

[@Hunter_s_morrison]

@@johns.6570 does it have to be in neutral ??

[@Hunter_s_morrison]

@@johns.6570 does it have to be at full rev when started

[@johns.6570]

@@Hunter_s_morrison yes in neutral otherwise it will take off on you , and thers a stop so you don’t get full rev

[@Hunter_s_morrison]

@@johns.6570 thank you I will let u know how it goes lol

[@sstatic6093]

get a drone so you can see everything

[@johns.6570]

You need a drone pilots license here in Canada

[@borillkageza1443]

good job but the 25 hp with a 10x13 Prop can take the same top speed and accleration. Before you tunes up your engine, change the original prop 10 1/2 x 11 to 10 x 13.

[@mctrun]

i just purchased a 1975 johnson 25 hp. Was going to purchase a 35 hp carb, but after your comment. i might just change prop. You are saying with a 10x13 prop i can/could get 35 hp speed? ✌

[@floridamansgarage8629]

I got a 13 pitch prop for my 25 and it would do over 30 mph and now with my 20hp I changed from a 9x10 to a 9.25x12 which I yet to have tested but I'm sure it'll be over 30mph.

[@joe-hp4nk]

You have to buy a 35hp to get the intake and carb, why not just use the 35hp? And if the 35hp has a bigger bore and stroke, the 20hp will never get to 35hp.

[@johns.6570]

Wrong 20 and 35hp s have same bore and stroke do the research, I’m talking about the twins not the triples, triples are completely different engines that are complete nightmares.

[@jsnbrgn608]

Goof guy

[@nicolaslimnell9280]

You need different propeller or your motor will blow up because it is overreving

[@johns.6570]

It’s not overrrevving it’s utilizing max rpm

[@nicolaslimnell9280]

@@johns.6570 but atleast your boat would go faster with different prop

[@johns.6570]

If I was overreving the engine I would be hitting the rev limiter, and the motor would be cutting out!

[@nicolaslimnell9280]

@@johns.6570 ohh I didn't know this has a revlimiter, becouse my 20hp (modded to 25hp) johnson does not have a revlimiter

[@johns.6570]

@@nicolaslimnell9280 I ran 10x13, made 34mph, great hole shot, I went to 10x15, not as good holeshot, but gained 1mph, it’s where it has to be,in its current setup,10x13 is only 500rpm increase in engine speed.

[@matthewowens455]

Not 35 maybe 25

[@johns.6570]

Wrong ! Faster than any 30hp I lake tested!,

[@matthewowens455]

Damn I just don’t belive a intake and a bigger carb would add 15 hp

[@johns.6570]

@@matthewowens455 it’s just not a intake and carb, it’s physics flow rates and dynamics, I just come up with another mod nobody’s done it before huge exhaust ports, big carb and intake, in the barrel this motor screams!,the 20,25, 30, and 35 of this generation is all the same engine with only different carbs and intakes.so swap out carbs and intakes for better and bigger flow and it makes HP.That’s how OMC did it charge customers way more money for little cost to them.

[@matthewowens455]

@@johns.6570 so you bored out the intake ports? I have a Johnson 70 hp on my boat I’ll do this if it really impoves hp

[@johns.6570]

@@matthewowens455 Nope I used factory parts from various years to achieve this , thers a 20 year spread in the design of the old and newer stuff..I used some newer stuff and older stuff my 35 sounds like 40hp at least…

[@jsnbrgn608]

LIES