Yamaha 15 HP, foward gear removal, help

kodibass

Master Chief Petty Officer
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Apr 10, 2010
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864
I was given a 1988 (?) 2 stroke 15 hp yamaha motor, which has a chewed up forward gear, I have located a parts lower unit that has a long crack in it, I want to swap the forward gears, how do I get the pinion gear off the drive shaft and out of the way to get at the forward gear? there looks like a 12mm nut holding on the pinion gear? do I remove this nut then pull the drive shaft? I never have done this before so its all new to me, the gears, dog, etc in the lower unit with the crack all appear to be clean and in good shape, just need some help figuring all this out thanks
 

boatguy823

Petty Officer 3rd Class
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Apr 18, 2006
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75
Re: Yamaha 15 HP, foward gear removal, help

a word of advice............unless you have a yamaha service manual and the CORRECT tools do not attempt replacing the gear. It involves a complete disassembly of the gearcase and involves what is called shimming Yamaha tolerances are very close and if your measurements are off slightly then you'll be doing it again and very soon. Your best bet is to find a decent used lower unit assembly and replace the whole thing.
 

kodibass

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Apr 10, 2010
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864
Re: Yamaha 15 HP, foward gear removal, help

thanks boatguy823, but in my case not much choice, I live on a Island off the Alaska mainland, I found the gear on-line for $15.00 I'm gonna give it a try, I will be looking for a lower unit but very un-likely locally, so can always hope!
 

99yam40

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Sep 7, 2008
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8,851
Re: Yamaha 15 HP, foward gear removal, help

Do you have the service manual for that motor?
It should give the procedure for removing and reinstalling and what tools are needed.

I have never done this before myself, but I would think that your thoughts are correct, remove nut and then pull the drive shaft so that the rest can be disassembled.
paygood attention to what comes out and in what order.
Maybe as long as the case is not damaged you will be able to just reuse the shims that were in it.
Maybe best to find someone that does it all the time and ask to be sure
 

kodibass

Master Chief Petty Officer
Joined
Apr 10, 2010
Messages
864
Re: Yamaha 15 HP, foward gear removal, help

Yep so far that's what I have done I took out the drive shaft then as the pinion gear dropped down I took the washers and shim out, then the bearing washer, I videoed the procedure and have things laid out in the exact order for re-installation. It looks pretty straight forward, and just today I was loaned a manual, it really did'nt give to many pointers tho. anyway as soon as the pinion gear arrives I'l give it a go. thanks' kb
 
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