Parts interchangeable between 80s and 90s 90hp Yamaha 2st

[even125]

I spent all my savings on the hull now need to buy a budget engine to run for a while till I recover some:$

I have found a 90hp 89 model 25 inch engine that has only 20 hours since a power-head rebuild for a good price, big problem is my boat has a 20 inch transom.

Are the gearbox's on these engines interchangeable thoughout the years? or did they totally redesign the engine in the mid 90s.

Any advice much appreciated.

regards.

 

[deejaycee_2000]

Re: Parts interchangeable between 80s and 90s 90hp Yamaha 2st

.... why not just get a jackplate? .....

 

[Ray Neudecker]

Re: Parts interchangeable between 80s and 90s 90hp Yamaha 2st

The gear boxes are interchangable even though a jackplate would be a lot simpler.

 

[even125]

Re: Parts interchangeable between 80s and 90s 90hp Yamaha 2st

Thanks for the info, I have already bought my hydraulic steering which is the solid front mount type (k6 I think), suspect it will be hard to mount on a jackplate, don't know for sure though.
The boat is a 19foot aluminium so extending the transom would work too, but it's new and I am shy about that sort of thing at least until later.

If anyone knows, are the powerheads also interchangeable? that would be nice for choices later on, sounds like they are the same motor througout the years?

All I know about these engine is they are a very reliable engine.

Suspect I will be visiting this forum a fair few in the future.

cheers even125

 

[ghind]

Re: Parts interchangeable between 80s and 90s 90hp Yamaha 2st

K6 cylinders bolt to the motor itself, actually the motor bracket. Should not present any problem for using a jackplate.

 

[JADED]

Re: Parts interchangeable between 80s and 90s 90hp Yamaha 2st

When you mount it check the clearances at full tilt and full lock in both directions.
Mount your engine on top holes of jackplate to give extra clearance.

 

[Ray Neudecker]

Re: Parts interchangeable between 80s and 90s 90hp Yamaha 2st

I would suggest the Bob's machine shop convertible plate at the 2 1/2 inch setback and the engine mounted as high as posible on the plate to start with. It make take some testing to get the exact height for best performance. Start low on the plate height adjustment and raise till you get the right height. Watch your water pressure as you go up.

 

[JADED]

Re: Parts interchangeable between 80s and 90s 90hp Yamaha 2st

even125

If you don't have jackplates available in Cairns you can temporarily use some Steel or Aluminium channel to raise the engine until you decide what to do. Much cheaper option. if you look at the vaious jackplate sites you will see the fixed ones.

http://www.cook-mfg.com/