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View Full Version : '98 yamaha 90h



nigelr
29-07-2010, 07:47 AM
Looking seriously at a boat with this motor.
Reputedly has not had a lot of work, with very little use over the last year or so.
What should I be wary of?
I will be factoring a major service into my offer, am thinking de-coke, water pump, impellor, plugs, gear oil, etc any other posibilities I should factor in?
Anyone owned/worked on this motor, grateful for all comments.
Cheers.

Noelm
29-07-2010, 11:04 AM
So, is the 90H a 4 stroke, or the ever reliable 3cyl 2 stroke?

nigelr
29-07-2010, 12:17 PM
Sorry Noelm, it's an 85hp, but yep it's a 2 stroke, I assume it's a 3 cyl...........

Crunchy
29-07-2010, 12:26 PM
Obvious I guess but make sure you do a compression check....

Jarrah Jack
29-07-2010, 12:44 PM
Yep compression check will tell you a lot. Also check the thermostat and you'll see if there is much salt build up behind it. Just found one of mine had a little stone in it stopping it from closeing properly. Made the telltale a bit weak. ( thanks Garry) Check the anodes and resurface or replace if badly pitted.

Hope that helps...Just learning a few of these things myself..

Noelm
29-07-2010, 12:48 PM
very simple engine, easy to fix and fool about with, only problem they had (as do a lot of Yammies) is salt build up in the cooling passages, give it a good run over 4,500RPM for a bit and see if the over heat alarm comes on. Other than that, the usual second hand motor checks will be all that is needed.

FNQCairns
29-07-2010, 01:15 PM
yeah that engine has next to no serious flaws, I have the 90 on my boat, they are slow, low torque engines compared to other offerings but they will keep on keeping on.

A little tip with internal mineral build-up, ensure the engines cooling system is in tip top condition,popets/thermostat/impeller because temperature turbo charges the formation of these minerals.

Wayne_Red
30-07-2010, 05:58 PM
Being an 85hp it is probably a CV motor, premix fuel, alloy prop etc. Yamaha made them in several sizes, they were no frills motors to keep cost down. Probably basically the same motor, not real sure, from memory I think the cowls were a bit sqaurer than the 90 of that time, might have been the same cowl as 90hp in the 80's? Not sure if they still make them? You could get a 3 cyl 90 oil injected etc etc or an 3cyl 85 CV. You could also get a 3cyl 30 or a 2cyl 30 CV, can't remember what other sizes were available but there were only a few.
Wayne

Wayne_Red
30-07-2010, 06:03 PM
http://www.coastal-marine.com.au/Yamaha/2stroke_CVEnduro.htm

There you go, just did a google search and found them
Wayne

rocklobster
30-07-2010, 08:31 PM
The only difference between the 85 and the 90 was the oil injection i had a 97 model and an 05 and they never missed a beat

nigelr
31-07-2010, 02:50 AM
Thanks everyone, much appreciate your time. This one has a SS prop from somewhere, might have come from the 90.
Cheers.