Separating powerhead from base help, 90hp Yamaha

[even125]

ATM I have this 2 stroke engine hanging from a rafter down stairs with a few safety bolts so the two portions will not separate with a crash, I cannot get the base gasket to separate, all of the bolts are out/loose that are shown on the new base gasket, I have done this to a few other engines over the years but never a Yamaha. Have shaken the scat out of the whole unit with no luck.

My manual for some reason completly skips this bit of my engine in the Powerhead removal/disasembaly section, as if by magic they believe it separates:}.

Anyone got any suggestions short of pulling it at 40mph down to the shops behind the car?? Which did seem like a good idea at one stage.

My only thought, is there a bolt or 2 that is not shown one the base gasket etc. or any other hidden bolt? any advice general or specific much appreciated.

I am trying to pull the powerhead as a complete unit to change the shift rod.

I really do not want to wedge the surfaces apart -yet, how do the experts deal with a problem like this.

regards and thanks even125

 

[Ray Neudecker]

Re: Separating powerhead from base help, 90hp Yamaha

Corrosion is a mean animal. You might try pulling the gear case in case the drive shaft is the problem. It can stick in the crankshaft.

 

[even125]

Re: Separating powerhead from base help, 90hp Yamaha

Yep, corrosion is a swear word!

I did get it, had to be a bit rougher than I wanted but no damage done, which is all that matters I suppose.

Every step with this engine is a learning curve, by golly! (for the want of a better phrase!) they use a lot of mild steel on these engines!!

cheers even125

 

[JUSTINTIME]

Re: Separating power-head from base help, 90hp Yamaha

Re: Separating power-head from base help, 90hp Yamaha

Yamaha has had problems with there power-head bolts
one of my teachers worked on 8 different yami's
i think he broke 8 out of the 12 bolts that mount the power-head on the mid-section
he told me if u have to use heat u are doing something wrong

 

[Ray Neudecker]

Re: Separating powerhead from base help, 90hp Yamaha

If he works on many saltwater engines, he may change his philosopy. I don't think many of the older more experienced techs will agree with him. If it doesn't come apart the way it should because of corrosion, he is likely to destroy more than he fixes without the proper use of heat. The problem even 125 ran into did not have to do with bolts, but just the normal corrosion problems that come with all saltwater used outboards regardless of brand.
I have noticed that the use of a high quality lubricant such as anti sieze on the bolts when assembling a motor to be used in saltwater tends to eliminate the problem.

 

[bosavy]

Re: Separating powerhead from base help, 90hp Yamaha

i have a 115 di u get at the smaller bolts in front undeerneath di

 

[bosavy]

Re: Separating powerhead from base help, 90hp Yamaha

i have a 115 .did u get at the smaller bolts in front undeerneath there 8 on mine 6 large ones 2 small

 

[JeffSki]

Re: Separating powerhead from base help, 90hp Yamaha

I am now in the same situation, trying to remove the powerhead on a 1997 90 Yamaha. I have removed the nine 8mm bolts from below. Are there any more? What next???? It really seems to be stuck on the base.