Reviving a Mercury 15 hp(Can it be saved?)

In this video I restore a 2003 mercury 15 hp. This motor had shifting issues, running issues and major cosmetic issues. Follow me as I restore this one if a kind motor back to a reliable motor. Thank you guys for watching!!!
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[@deanshupac8774]

Best video I found 👍👍👍👍👍 Perfect now to fix up my 15 hp Mercury

[@outboardfinatic]

Awesome thank you so much for the feedback. Have any qs lmk I also have some other vids similar to these 15s so you can also relate to those if need be. Happy fixing and hopefully you can get yours up and running smoothly

[@SaltLife4Us]

Cool rebuild. For future videos, it would be cool to show top end speed hit on your phone for all the motors you rebuild. Great content.

[@outboardfinatic]

Will that’s a good idea appreciate the feedback

[@ucan011]

Good video, but taking that carb out looked so much harder than it needed to be, when i remove this id just remove the idle speed control/choke plastics, its only a clip and it all comes out. makes pulling the carby out so much easier

[@outboardfinatic]

I do this way so I don’t have to remove anything else if I don’t need to. It’s actually really easy. I know what your saying and I’ve done that before. But I found it easier just doing it this way and I typically can install one in 10 secs if yhag

[@dennis6325]

That is called a "lean sneeze". All these 2 stroke mercs do it. Just richen the mixture screw until it stops. You may even notice it will not do it in the tank but starts to do it again when under load on the boat. Just turn mixture screw out 1/4 turn at a time until it stops. My 9.9hp is about 3 turns out from the stop. Very unique, cut common for these merc outboards to have the screw way out.

[@JackJack-rj8tw]

Oooh those flush cuts

[@scottpetrie8707]

Buddy. First time here. Nice job.

[@weswhitlinger1706]

As mechanic for more than 55 years, and someone that has probably worked on more outboard motors than most people have ever seen, I'm telling you that there is NO way an outboard motor can "slip" as you called it when in gear, there is no clutch, it is direct drive gear to gear. Reverse on these are limited to how much throttle you can give it, on top of that the prop is not designed to have very much bite in reverse.

[@outboardfinatic]

My pronunciation of things rn still aren’t the best. I know all this but I tend to have trouble saying the things I’m trying to think. Hence why a lot of times I just show what I’m doing rather than talk. I appreciate the feedback and im still learning. Im only going into my 3rd year as a technician and I just do these little motors on the side for fun. I hope you comment on further videos so I can make sure I get it right

[@mazwirashahdan]

Good job! Love your video.. keep it up

[@warreng3142]

So glad I found this video, as my motor is a 1988 15hp, very similar setup to yours, rebuilt the carby due to the diaphragm having a leak, after starting and running, there was a lot of dirty oil in the water? is this normal? also, I will be now looking at the shift linkage as mine is also not sitting where it should be on the tiller handle and not going into gear properly. Also at what distance did you set the little clamp on the shift linkage to??

[@outboardfinatic]

Hi there appreciate the message. Pretty normal for these 2 strokes to have a lot of carbon built up in the cylinders. Hence the dirty looking oil in the water when running. Try using quicksilver powertune. Should clean up the cylinder walls and exhaust cavity. Beware tho you will see a lot of black coming out. Don’t be worried completely normal. That little clamp should just be touching the forward release. That’s the lever that you see in the mid section. Put the engine in neutral and put it on just so it’s touching that lift assist. When you shift into forward that latch lifts up and allows the motor to tilt if it were to hit a rock or something of that nature. Hope this helps

[@Showmethefish]

Great job

[@outboardfinatic]

Thank you

[@davidcastano7009]

Hola me podría alludar q número de chicle lleva el 15hp gracias

[@sharkman5735]

I subscribed!!!! Thank you. I have the same motor!!

[@chadschafer3890]

Heres a question you might not know, what size jet did that have in the carb

[@yndalecioluna6081]

I have a 6 hp mrec 1998 can you make a vid on the choke system and how it works i just rebuilt my carb not sure if my choke is installed right thanks for the vid very good info

[@outboardfinatic]

4 stroke or 2 stroke? Have a video on a mercury 6 hp 4 stroke

[@serdarbozkurt2348]

Great job! What kind of liquid do you use in the utrasound cleaner ?

[@outboardfinatic]

Spray nine and distilled water

[@k3nny903]

Great video man! I own a 97 merc 15 hp and it runs great. I have been having some issues when i try to start it. (Pull start) it sometimes kicks back and the cord rips out of my hand. Almost as if the ignition was off timing or something. After a couple more tires and kick backs it finally starts and runs great lol have you ever dealt with that issue before?

[@outboardfinatic]

Mmmm. Timing usually doesn’t go out of wack on these 2 strokes. Its extremely rare unless something broke. I’ve never had that issue but it could be excess fuel in the cylinders or even carb build up that causing the engine to back fire on you. Meaning it’s igniting something before it’s suppose to. These tend to always have a lot of carbon build up just from over the years of running. I personally use quicksilver powertune which will completely clean the cylinders of carbon build up. Cus if there is a lot of build up it could be igniting it etc

[@k3nny903]

@Outboard Finatic appreciate the info man. Gonna try to use that and see if it helps 👍

[@andersoncarvalho9297]

Ola eu pedir a esfera do afogador vc sabe o diâmetro da esfera ????? 😮😮 A medida da esfera???

[@liamrossiter1427]

This was dope exactly what I needed I’m picking up the exact same motor today for 100 let’s see if she can be saved 🤣🫡

[@outboardfinatic]

Good luck I hope it works out for ya

[@yicafresh]

Hi I have just this outboard in a 1997 and she is running sound but only getting 80 psi on each piston ? Does that mean it nearly close to been broken ? Thanks Glen

[@outboardfinatic]

Pretty much if the max ur getting is 80 on both or just 1 she’s pretty toast. Helps if you have a camera to check out the cylinder walls to further diagnose. The motor still will run but may experience weird hiccups here and there

[@yicafresh]

@@outboardfinatic thanks for your reply .. is it a big job to do piston and rings on them ?

[@damian31746]

After reading these comments, it seems these are a low compression engine that can't be rebuilt. Can the compression be raised a little to improve power or is there any other modifications to get a little more out of them? I have a 2008 15hp Mercury USA build. It runs real well but I would be great to have just a little more grunt to get on the plane with 3 guys in the boat. It does it great with just me, struggles a little but gets there with 2 guys, but falls just short with 3 guys.

[@outboardfinatic]

Not possible. Most of these powerheads for these years are one and done. They can’t be rebored and no there’s no way to increase the compression. The only thing to do is maybe adjust the idle mixture screw a little out so it gets more gas but that’s just about all your gonna be able to do. Unless your pitch on your props not right for your boat or something

[@brantbertagna7637]

I have one of these on my drift boat I just bought. You wouldn’t happen to have any idea what would be the cause of a ratcheting sound when using the pull start? It does it intermittently and sometimes won’t start the motor depending on if it’s cold or hot?

[@outboardfinatic]

Could possibly be slight in gear still and when you pulling it it’s making the gearcase ratchet. Make sure your linkages for you shift are in the proper spots.

[@andrewrose7172]

Did you add the electric start yourself?

[@outboardfinatic]

Nah it was already on the motor. I just fixed up a lot of the stuff. You can easily add electric start to your outboard as long as you have a flywheel w teeth for a starter. Otherwise you’ll have to get a different flywheel as manual start flywheels are different

[@carrollgosnell5907]

I couldn’t find the link to the kit for 15 hp mercury carburetor does a 19269 sound wright

[@outboardfinatic]

Sierra #18-7212

[@liamdanials131]

Hi I have a 10hp mariner 2 stroke do u kmow if I can fit a 12 volt charger socket

[@outboardfinatic]

What do you mean by this? Are you talking about a voltage regulator for the motor or like actually installing a 12 volt socket on the motor to charge your phone etc?

[@liamdanials131]

Hi yes I am trying to install a 12 volt charging system on my 10hp 2 stroke mariner

[@JetSkiBuyFixPlaySellChannel]

Not seeing the link to the carb rebuild kit.

[@outboardfinatic]

Sierra 18-7212 carb kit

[@JetSkiBuyFixPlaySellChannel]

@@outboardfinatic thank you.

[@gileskulaga3389]

What kind of spark tester is that?

[@28704joe]

I wish you'd have confirmed/set the timing and set speed with a tach. That info is hard to find on video.

[@outboardfinatic]

I can do that for future vids. Never really have to mess w timing w these unless something has broken. Other outboards yea but these not very often. I do all the tuning and idle speeds by going off my ears and listening to the motors. But for you guys I can get a tech and such so you’d can see what I’m talking about when I say I use my ears to listen to the motor

[@28704joe]

That would be swell. My outboard got the timing screw screwed with so I had to put a timing light on it@@outboardfinatic

[@mrpanda2655]

I have one of these models. Dont know the year though. Its missing the idle control linkage and its leaking gear oil from the weep holes right above the bottom end. Any clue what it is? Im thinking the driveshaft or shifter seals.

[@outboardfinatic]

As far as I’m concerned that oil your seeing it’s carbon from the exhaust cavity. Especially on these models they build up a lot of carbon over the years. Could use powertune from quicksilver and will get rid of all the black oil residue. You certainly could’ve blown a seal but easiest way to find out is crack your gear lube and if there’s a leak you’ll see creamyness in the gear lube. Only other thing you could do to see if you have a seal leak is just pressure test the lower unit to 10 lbs and you’ll see bubbles if ya have a leak. Hope those helps

[@mrpanda2655]

@@outboardfinatic yeah the oil was mixed with water. I think its the impeller housing seal thats bad

[@andrewszot3094]

My 98 15hp has that same stutter at idle. Runs good otherwise.

[@outboardfinatic]

It’s a lean sneeze. Too much air and not enough gas. Try adjusting your idle screw and see if it goes away

[@andrewszot3094]

@@outboardfinatic thanks man, I will.

[@timsussenbach5376]

When you hear that puff its usually the reeds or fuel pump

[@outboardfinatic]

I agree only problem was carb was rebuilt with new fuel pump. Fuel pump is built on the carb on these. And reeds we’re fine I always check the reeds when doing these. My thought process is motor was sitting awhile probs had bad gas in cylinders and carbon built up. And needed the right carb adjustment. Hasn’t done it since the vid so think I figured the problem out. Thank you for the feedback tho!

[@timsussenbach5376]

@@outboardfinatic i was just saying it because it idles pretty high so i though you turned up the idle since it mostly happens on low idle.

[@outboardfinatic]

Yea during my diagnosing I tinker with it a lot to figure it out. Some parts of the vid it is higher cus I was diagnosing it. A lot of footage gets cut out due to timing unfortunately. Have it set to 1 1/2 turns to 1 3/4 and motors been running great and idles nice on the lake. Haven’t had the issue occur anymore really think it could’ve been old gas and possibly just a combination of things but all is good now. Really appreciate you commenting

[@timsussenbach5376]

@@outboardfinatic if you keep goung like this you will be very succesfull

[@outboardfinatic]

@@timsussenbach5376 thank you that means a lot. I do this as my day job at a marina but love doing these on the side at home. Wanna get into the bigger stuff but have to wait till I get more equipment and space lol

[@thedub7467]

Is it true that the only difference between a 9.9 and a 15 is the carb and that you can replace a 9.9 with a 15 and have a 15hp motor?

[@outboardfinatic]

To a certain extent. Has to fall between a certain serial range. Some older ones have small intakes etc and can only be a 6,8,9.9. And then the 15 had bigger ports. Some of the newer ones the 9.9s and the 15s are the same and it’s just the carb difference. Bigger jets etc. as far as my knowledge

[@thedub7467]

I don’t even know what year mine is. I can’t find any markings or stickers anywhere.

[@paulbellefeuille2289]

Is 108 and 105 compression not low?

[@paulbellefeuille2289]

I have an 8hp that I took to a mechanic for rough idle. Told me it was low compression. Same compression as this motor. Said my motor was junk.

[@outboardfinatic]

Sorry to tell yea but these are low compression motors. Whoever you took it to didn’t know what they were talking about. There’s a wide variety of readings for different outboards etc. but these specific models I’ve never seen them hit above 110. If it’s lower than 90 it probs won’t run either. I also go in with a borescope camera which tells me a whole lot more about the condition of the motor. But the answer to your gs is no 108-105 is not low for these outboards

[@outboardfinatic]

Your running issue could be carb issues, or reed issues. But tht compression wouldn’t scare me at all and your issue is somewhere else in my opinion

[@paulbellefeuille2289]

@@outboardfinatic Thank you. I will have to look deeper.

[@paulbellefeuille2289]

@Outboard Finatic I just checked the compression. 91 and 95. Guess my guy was right. Can these be rebuilt?

[@chuckd02]

Could incorrect linkage effect top speed?

[@outboardfinatic]

As in the lower unit part? Cus if so tech you’ll never even be able to get in gear and you’ll just be tearing up the clutch dog and the teeth if the gears in the gear box

[@chuckd02]

It goes into gear fine both forward and reverse. But I feel like at top speed I’m getting about 10-12 mph. I’ve ordered a new prop to make sure the old one isn’t spun but I was just curious as to what could be my cause Could the throttle linkage maybe have something to do with it?

[@chuckd02]

It’s a 1990 mercury 15 hp. That hasn’t been ran in over 10 years. I just got it and am working on it to get it back right

[@outboardfinatic]

We’re you able to check compression? Low compression will cause it to lose top speed. Or if you check your throttle linkage and move it to wide open. Look in the carb and make sure the butterfly is completely horizontal. If it’s not that’s your issue

[@outboardfinatic]

It could also be the prop cus having the wrong pitch on certain boats can also do that. What pitch you running and what kind of boat you got?