1998 Yamaha 115 - Overheating Fix

In this video I documented the steps I took to fix an overheating issue which included an attempt at flushing it with Rydlyme and then the work necessary to manually clean the water jacket and heads.

[@accountingstepbystep2229]

Great Video! I had the same problem with my Yahama 135 and ended up doing the same thing you did to solve the problem. But I didn't try the salt-away products because I researched a bit, and like your video shows, they don't do anything to fix the problem. So purchased the head gaskets, the head cover gaskets, the thermostat gaskets and removed the thermostats, the head cover gaskets, and the heads. The inside of my engine looked even worse than your engine did, but I scraped all the sand, salt, and whatever the mas of sediment was out as best I could. After I put it back together, the overheating alarm stopped tripping and the temperature readings went down for the 150s to the high 120s, low 130s, just like they did for you. You really did a great job with the video and I am sure it can help someone that is having illusive overheating issues with their Yahama outboard. And, you demonstrate that if you are a somewhat handy do-it-yourselfer, you can get this job done, no problem. Thanks for sharing!

[@BlastedKat]

Rydlyme! Amazing stuff. Flushed my 1998 yammy 250 SW II for 6 hours with a 1600 gph pump with a 50\50 solution of Rydlyme. It poured out back gunk for 2 hours. Problem solved.

[@raineperez1003]

Great video. I ran into the same issue with mine. I have a 1998 Yamaha 115hp 2stroke, wish I had seen this video when mine was overheating. Thank you for the video

[@nomad7412]

If I can give the same advice as I gave to another guy who was having similar problems. Try giving Dangar Stu a look. He goes through an explanation of the cooling of a 2 stroke engine. He is a marine engineer and his info has saved many novice from disaster. He is on youtube. His educative videos have been used in marine colleges over there and might have saved you some headaches. From watching him diagnose many engines, I believe he could have made your diagnosis much quicker. Well done for that. However a greater understanding of how the cooling system works etc might of saved you hours of head scratching. In one of his videos he used 3 cleaning methods (including Salt away). I suggest (for greater understanding) You should watch the video on cleaning outboard water passages. Regards :] ( and hope it helps for future problems.

[@Kevin-hy6ln]

Thank you!

[@crispernator]

I follow stu and eddi the wonder dog for ages now his info is really good found out he grew up about 10km away from me here in adelaide

[@howardsway782]

Great video, well done, thanks for showing. Note - White Vinager is the best at dissolving salt and rust.

[@robertjackson7590]

If you remove the part like the heads find a machine shop and see if you can "glass bead" the corrosion. 10 minutes later it'll be down to bare metal. Check or replace the Anodes in the engine bc they'll look like this. Don't use sand for blasting bc it cuts metal, you naturally don't want that. You did a great job considering.

[@jassoncaltzontzint]

Awesome video thanks for uploading, my 99 150 TRP is doing the same thing

[@MikeSki1984]

I'm getting ready to do the same thing. '96 200hp Saltwater Series II. Thanks for this vid!!

[@lesleysmith429]

Bought a Yamaha 55 up 37 years ago. Had a machine running aft fluid fail so drained 30 gallons of atf fluid out kept it and ran outbound in it at end of each season .it still looks new! Just changed pump and housing gadgets every year incase oil damaged impeller.(no sign of damage).cost nothing but kept corrosion at bay .even had atf from tell tell .haven't looked inside water jackets as never needed to .worked for me will run it untill it wares out . was on small ski boat so a lot of full throttle running

[@ther1rida]

VERY VERY GOOD FULL BEFORE AND AFTER! thank you

[@christianasero4720]

Damn your smart, wouldent have ever though of this! Thanks man

[@blakethesnake1555]

Excellent video. I’m in the same boat. Just changed poppit valve. Thermostat and now I’m about to replace water pump. My engine is 20 yrs old 90 hp 2 stroke Yamaha. I’m sure I have corrosion even though I’ve always flushed and even had it professionally de scaled. Which is what you did in beginning of video. Do you happen to know where I can find torque specs online? If I have to pull heads. Thanks for making this video. I owe you one!

[@brentstephen5537]

Great video. Thanks. This gave me the confidence to dive in. Problem solved.

[@dibochet]

Thanks for the video! I am going to try this out and see if I have the same problem I have a Yamaha 115 Inshore (small guarded inlets for water impeller) 2-Stroke and have been having this problem. Couldn't tell if it was a problem with not enough water getting through the system, so I got it acid flushed and ran a wire through the "pee indicator". It's pumping water like a man man, however I am still tripping an alarm. I assume it's the temperature alarm because like you it only goes off when I'm trying to get up above 1/2 throttle. It could also be a voltage problem because I had a dead/failing battery. But I want to take the heads off to take a look because I am going to have to drop the money to get new batteries anyway.

[@bobbell5928]

Used barnacle buster before taking apart a 1999 saltwater motor for a rebuild. It was completely clean. Think flushed it for 2 hours

[@eallanboggs]

I used a 120 quart ice chest because my lower unit it so big. I filled the well under water ice chest with Salt Away , Vinegar, Bleach, Muratic Acid, Baking Soda and water. I started the motor with pick up well under water. I also had the garden hose hooked up on the flush port on the bottom of power head As water would splash out I would as some more water This method RECIRCULATES the flush over and over again The only thing is the engine is running so the water gradually gets hotter and hotter After about 30 to 45 minutes the alarm sounds to I shut it off right away I drained the flush into 5 gal buckets so I could use it again I then filled it with clean water and ran it again to flush out the flush As I drained the flush I saw a lot of crap and debris in the water The main thing is watch your water pressure gauge If it gets below 10 change your IMPELLER

[@josesantana561]

Great video. Appreciate the way you carefully diagnosed through the problem. Can you post a video on how to disassemble the head/water jacket?

[@BataviaVids]

There's not much to it. You just take out the bolts holding the head on.

[@Gabe-jz9ry]

Awesome video. Hope this works for me

[@bobbymentel]

yes great video thanks for posting

[@BigMkombe]

Great job cleaning it out. don't know if I missed it but did you check the poppet valves? usually associated with higher rpm overheating issues.

[@Kevin-hy6ln]

I replaced the poppet valve the year before.

[@ricardogarri9696]

Poppet valves if stuck open create low rpm overheating.

[@alangrant5278]

Nice vid thanks. Just a thought. If you have to drop the bottom end off to take out the impeller could you just connect your bilge pump’s to the water pipe that the impeller feeds? Would save putting the bottom end on and off again and also all the water would be used instead of some leaking out the upper intake?

[@Kevin-hy6ln]

Yes, I did a follow up to this video where I removed the lower unit and flushed it. Take a look kzbin.info/www/bejne/r5K8Y2yKj8dpoZI

[@JaymanTelemark]

Hello, I have the same motor, It will newer pass 2500 rpm.. Maybe same problem? How can you see overheating? Alarm? What speed and rpm is max on this motor? (Steel prop on 19' Campion boat)

[@lbowsk]

Getting ready to do the same on a 2014 V6 Yam F300. Using a product called Barnacle Buster. Overheating at high RPM.

[@joshuaneal4125]

I own a 98 Yamaha 150 saltwater series 2 stroke. Mine ran fine until I put sea foam in the gas tank to help with the rough starts. I've always used ethanol free premium fuel and amsoil marine pre-mix. Over heat alarm started after about 5 mins of run time with the muffs and water hose. I have now changed the entire water pump assembly, two new temperature control sensors, two 2 thermostats, new fuel/water filter, 6 new spark plugs, two new water jacket gaskets. Got all this installed yesterday at the house, hooked water hose and muffs up, cranked the boat. Ran fine for 5 mins and alarm went off AGAIN! Cylinder heads were extremely hot. Guess I'll take it to the lake and crank it cause probably not getting enough water pressure

[@josefbleaux6724]

How did it turn out? Did that fix the issue?

[@adAlqubaisi]

you need to check the oil injections as well those can also heats up the engine by not injecting enough oil.

[@zachmcdevitt5996]

I know this is old just want to ask anyways could you elaborate

[@psi23k]

@@zachmcdevitt5996 google vro (variable ratio oiling). Instead of using premix fuel and oil, you use normal fuel and an oil injection pump injects oil to lubricate the internals. If no oil, no lubrication, increased engine temps, then bye bye engine lol

[@peterburnham1169]

You also need to remove the computer between the two banks then remove the exhaust water cover and clean that out too.

[@rogerazcona804]

I’m in the same problem with my 1996 Merc 200 2-stroke. It’s peeing but overheats after running awhile. I’ve flushed with Rydlime for 4 hours. It improved but alarm still goes off. I’m going to remove the head gasket to inspect inside. I wonder if I can blow out any remaining debris with a power washer.

[@Kevin-hy6ln]

IMO when it gets to that point, it's time to pull the heads and water jacket and manually clean it out. Also, as pointed out in other comments, it's a great time to replace the anodes.

[@wtfjpgmailcom]

Next time use a dremel and a little wire weel to clean those heads and jacket

[@thomasflynn642]

Where did you get heat gun?

[@joseluisechapaca5816]

ebay or amazon around 15 $

[@richarddomsicz670]

how do you remove the engine cover?

[@brianparravicino163]

That clogging is nothing compared to an 8 hp Yamaha that I just took apart. Those water passages between the block and the cylinder walls were completely clogged and compacted with a white salt looking substance. Just because the tell-tale is working, it does not mean that the water jacket is not clogged. We all know that hot temps mean shorter engine life. I learned a cheap lesson on a cheap engine but felt compelled to share. Newer and bigger engines of course are set up with fail safes and shut downs .

[@MrLkeip]

im not a boat mechanic but all you did was flush the lower unit. none of the solution pumped up to motor.

[@BataviaVids]

That's correct. I did a follow up to this video on how I addressed made that correction to fix it.

[@jimwoods9551]

The pump design is positive displacement rather than centrifugal. Therefore no fluid will pass through the pump unless it is running. My experience with non corrosive flushing shows it to be useless for de scaling as in this video where he immersed the heads for an hour. I strongly doubt if regular flushing with a surfactant flush is any better than wishing on a star. Acid descaling with a flush pump is high risk in an outboard engine, frankly you wouldn’t want to try it unless you’ve experimented with a lot of junk engines. Note in this video where the cylinder block suffered severe pit corrosion on the sealing face, this presumably on an engine that hadn’t been acid flushed. Introducing acid into this scenario and the likelihood that rinsing won’t effectively reach poor circulation areas is not sensible. Do the righteous thing - get out the spanners. Leave the magic potions to the marketeers and the gullible.

[@JamesWhite-tg4kw]

@@jimwoods9551 so what are you saying Jim. Flushing wont help anything. Tear everything apart and clean by hand

[@jimwoods9551]

@@JamesWhite-tg4kw You can flush the engine through the flush port, when you screw the special nipple into the flush port (I assume all outboards are so equipped). Alternatively immerse the foot in water or use “ear“ muffs, but you must run the motor to circulate the water. It’s quite a work up for the frequent user and I doubt it’s of any benefit unless you think you’ve pulled in very muddy water. As for flushing chemicals - save your money for drinking alcohol. When you need to decongest the cooling system, roll up the toolbox.

[@thediplomasta5891]

You didn't flush the motor with the ridlyme. You only flushed the water pump pickup. That yamaha flush adapter feeds water to the impeller. Your engine was not turning, so none of that stuff went up to the engine block. All marine 2-strokes must be turning, when water is introduced into the cooling system. Otherwise the water will backflow thru the exhaust ports and fill up the cylinders, resulting in a hydrolock. Most engines are designed to prevent you from doing this. The only exception is jet skis that use the drive pressure to feed water to the engine. If you hook up the custom flush adapter to a jet ski (on the trailer), and don't start the engine before the water, you will hydrolock it. If you don't want to start the engine, due to a product being heat sensitive, then you can pull the spark plugs out and spin the flywheel around with a corded drill (with a socket adapter). But only of the engine is small enough. 🤔 Might be tough on a V6, unless you have a beast non-impact drill. But anyhow, the water pump has to be turning with the engine, together, to do what you were trying to do. That is why the impeller is fixed to the driveshaft. One, can't be turning without the other.

[@guyanesegamer1693]

55 gallon barrel plastic cut it half and add white vinegar water 50/50 ratio and start it bump the idle up around 1000 to 1500 rpm and remove the thermostats make sure it’s pumping water

[@xXsupaXcaucasianXx]

When you flushed it you didn't start the motor, in for the solution to circulate the drive shaft has to be I'm rotating the water pump to pump the water through the block

[@BataviaVids]

When you take out the thermostats and pump water through it, it will flush through the block.

[@richardwolske2015]

Dropping the lower and hooking right to the up pipe and removing the thermostats let it pump for a couple hrs . Looks like the best solution? Good luck. And in salt water you should flush every year .

[@robertpc100]

vinegar works good and you sure you been rinsing that thing out.well i learned somethin

[@Kevin-hy6ln]

Yes

[@DustinKeating-yk3vq]

I have a 07 Yamaha 115 2 stroke and my heads dont never get above 90 degrees

[@Gramskee]

You need to flush with impeller in it with motor running, only way to clean upper cylinder water holes, your motor wasn't peeing during the flush so no chemicals made it to the top

[@Gramskee]

Also made needs thermostats in it that way you descale the thermostats as well, cause once motors warms up when idling the thermostats will open and flush entire motor

[@Kevin-hy6ln]

Yes, I did a follow up to this video where I removed the lower unit and flushed it. Take a look kzbin.info/www/bejne/r5K8Y2yKj8dpoZI

[@shouse5110]

ok heres my two cents. you should have left the lower end off. ran the pump hose to the copper water tube running up to the block that there would insure flow to the motor, as far as the tell tale well that should have a hose extended to the bucket to catch the fluid. me i use vinegar however you need to be carefull as far as its acidic.... Another way is to back fush thru the thermostat housings with a garden hose...

[@gurnblanstein9816]

It's not a weak batch. All that kind of stuff is just gimmicks for them to make money. The only way to do it is take it apart and manually clean it out like you did.

[@CaptDavesSportfishing]

screw that stupid vinegar, you used the better stuff. doing a complete flush of my 250 suzuki next week. do you have a oil or fuel cooler? my fuel cooler was blocked. don't think the other owner ever flushed that. those anodes should have been changed while in there.

[@johnpike5836]

it is a RESULT OF YOUR REAL ISSUE

[@deerlakediver5554]

The problem with any kind of "flushing" is that when your passages are plugged, no solution can get in to clean them out.

[@todaytriper]

Use it to keep them from getting plugged

[@tcap7917]

it would've done a better job if you had more volume (1 gallon wasn't enough) it was probably air-bound inside the cavities

[@leifpersson9192]

If that is fahrenheit, then you got no other problem then a broken temp sensor. There should be no alarms when engine is +60celcius. I mean the thermostats on the boat engiens i know about open the thermostat around +50 celcius. My volvos thermostat dont open untill around +90 celcius. Greets from Sweden.

[@Kevin-hy6ln]

Yes, these temperatures are fahrenheit so it was getting pretty hot.

[@leifpersson9192]

@@Kevin-hy6ln the thermostat i find for that motor opens at 52 celcius, and the highest temp u found was 67 celcius. for me thats nothing for a engine, i think it shouldnt sound any alarms for that, and yes there get allot of shit inside the channels in the motor but to clog up totally is rly hard but clog a little is easy hard to explain, i wouldnt see 67 celcius as a problem only problem is the alarm that rings on 67 celcius, if you know what im saying.. i hope it helps if not godluck anyways..

[@jefftaylor9882]

Funny how what he did fixed the temp sensor.

[@paulchace2391]

​@@jefftaylor9882 Is there a test to check sensor, hang it in water and heat while monitoring continuity?? Yes?

[@stevenjacobs6934]

Flushing never works, always a waste of time...heads and water jackets need to be removed and soaked in vinager overnight followed by good old fashioned elbow grease and a sharp pick tool!

[@storyoc]

what bout removing gearcase-plug the opening where the water goes up to the motor and den pouring vinegar thru the thermostat opening wo the thermostat till its full-tilt the motor so itll bee full of vinegar and let er soak????-im gonna try this as i run alot in the gulf here in florida-ill make a video and post it if it works-

[@stevenjacobs6934]

@@storyoc sorry, the head and water jackets need to be removed! Trust me, the scale is caked on in there.

[@nathanmayo7101]

Here's the latest....My Yamaha 50 was overheating ,but it would be VERY inconvenient to pull the boat of of the water. I backed the boat around by hand so the motor was in about 3 feet of water and I could stand next to it. I took out the thermostat and removed the prop and then surrounded the lower unit with a 65 gal collapsible plastic leaf basket ( Amazon.. $7.50) This separated the flushing solution from the rest of the lake. I dumped my 1 Gallon of Rydlyme into about 20 gals of lake water and fired it up, with the pee hole squirting back into the basket. I ran it 2X daily for about 5 minutes each time for a week. Is it squeaky clean? No, but way lots better than before and my heat alarm doesn't go on anymore. Yes, you must have flow throughout for this to work + enough patience to let the very diluted Rydlyme do its thing. I figure if I repeat it 1X/ year I will eventualy get squeaky clean, because nobody had touched this thing in at least 10 yrs.

[@osbornebay944]

You did it wrong by earmuffs and it may not flush heads and upper water passages, it should be pump fluid by water pipe and allow pee hose feed back to the tank.

[@dneuman7455]

Did you use a Descaling solution then a pressure washer.

[@jefferykirk2322]

Those holes are for head bolts ...

[@rodneyjohnston6280]

cylinder Wall are clogged up

[@edcan619can4]

After soaking covers rinse them with pressure washer

[@python71483]

i think you should have the motor running

[@user-ow7gl8lt1l]

Even me also

[@jimmygaribaldi]

You need a stronger pump to reach the top

[@danieldesimonedanny1827]

And every time it goes over 145° salt becomes solid. Yeah pull the heads apply elbow grease.

[@ernestsisto3087]

I'm glad ya fixed it. kzbin.info/www/bejne/pJvMqJmjr8ucm9U

[@Kimbeattie]

replace the poppet valve google it

[@michaelmurrietta2263]

Fill oil tank

[@bravowhiskey88]

yeah that it the batch is weak lol

[@nathanmayo7101]

I am disappointed with your RydLyme experience because I have a gal. arriving tomorrow. You did have the thermostat out, yes?.........so it should have circulated throughout UNLESS a couple ares were blocked completely so it could not circulate past those points. The company's video has got me believing that the product is invincible, so I will try your pump and circulate idea first, but maybe for 4-6 hrs instead of your 2. If that is a no go, THEN I will pull off the head like you did, but just soak the plates until they are slick clean with RydLyme or muriatic if need be, then reinstall and run the flush again, thinking that the open plates will now let the solution get way back into ALL the needed areas. Since you have the tub/pump thing down to science, maybe we should all be doing the RydLyme flush every year, not just when the buzzer goes off. I'm a dentist and we preach PREVENTION, not repair after the damage is done. Great video. I appreciate your efforts, and will try to report back what happens with my Yamaha 50 2 stroke.

[@ricardogarri9696]

Try removing the lower unit and pump straight in to the tube.

[@CaptDavesSportfishing]

YES.....YEARLY DOC! I PLAN ON DOING HRS AND HRS OF FLUSHING YEARLY WITH DESCALER.

[@osbornebay944]

Hot fluid is better.

[@michaelmurrietta2263]

Looks like that product doesn't work

[@rodneyjohnston6280]

Is garbage You would be better off to buy a head gasket and clean out the cylinder walls

[@Kevin-hy6ln]

I did put in a new head gasket after cleaning out the cylinder walls.

[@joeybunkerslgl15gbunker25]

I don't think that stuff is worth a chit