So I have started to tear down my 01 Yamaha 90 2 stroke due to it being seized. I have some machine shops in mind, but is there any local shops that rebuild powerheads? I would like to DIY (have the manual), but for the sake of time, interested to see who is out there and get some quotes.I have heard to use Simons in WA for the machining.
I see boats listed for sale with “rebuilt engines,” are they all DIY, or is there a reputable shop doing these? Dealerships asking almost the cost of a motor are out of the question. Trying to find a decent used 90 is insane, people think very highly of these motors.
if its a salt water block, check it very close before spending any money on it. Pull the exhaust plate and look at the water passages. Throw the cylinder head in the scrap pile and buy a new one
So in one last effort, I was able to free the flywheel. Before I got too involved I wanted to see if the oil I left in it for a few weeks helped. Lubed with more 2 stroke oil. And it is turning over.( little help from pull starter ) Honestly it sounds like it just has a bad top bearing. Brief squeak when turning flywheel and slight resistance. All pistons are moving back and forth and getting compression. Any ideas? Remove whole block still?
spareparts, I never had a low oil, or overheating alarm go off. It ran funny the last time I took it out. Thought it was bad spark plugs. When I changed them out and went to go start up it was locked up. Had a dealer take a look, they just said it was seized and I needed a whole new powerhead. I heard to put some oil in the spark plug holes and try to move it with a breaker bar. It never moved for about a month. Last night I went to try it one last time, and everything moved. its not perfect but its free. Starter is able to turn it, I have not tried it with spark plugs in yet. I took a video and a buddy thinks it might be a ‘driveshaft bushing’? told me to drop lower unit and see what it does. Could a part connected to the lower unit lock up the whole engine? My guess is it could be water, but wouldn’t it have worked its way out.
you are going to have to pull it completely apart and inspect all the parts to determine what is damaged.
then you can get an idea of what it is going to cost to rebuild it.
Other than boat dealers like myself, I am not aware of anyone that is a reputable builder.
A BRAND NEW POWERHEAD ASSEMBLY IS $2600
Is it possible that a bad drive shaft bushing could have seized the engine? I have seen a couple articles where it comes apart and gets stuck which then makes it extremely difficult to remove the lower unit. I am going to try to pull the lower unit tonight and see if it frees it completely. As you can see, Im having a hard time seeing that the actual power head is even damaged at all.
Mostly what Chris said, drop the lower, see if its any better.If its not, from what you are describing, it sounds like its corroded thru a water jacket and seized the engine. If so, you are looking at a manufactured long block, plus core(yours is probably junk). And it would be prudent to go thru the fuel system and electrical when you install a new powerhead. By the time you are done, you’ll be getting near $5000 in a 17 year old motor. Part the motor out and re-power, you’ll be far ahead of the game
So update, took foot off, put plugs in and it cranked and started on 2nd try. Compression tested 110 on all three cylinders. Little smokey, but it’s running. Gonna change water pump, and re install foot. Bushing in midsection looks intact.
So I put the foot on and ran it on muffs. Seems OK. Ran combustion chamber cleaner per can instruction. I took to ramp to run. Idled around a bit,started to push it on plane, all good. Took it back down to idle, it took a little more effort to get on plane second time but it got up fine. Rode around near ramp for a sec and took back to trailer. Shut off as soon as I got on trailer. Started right back up, adjusted idle 1/8 turn and it stayed on at ramp till I turned it off.
Lower unit oil is good, water pump is good. I need someone that can probably tell me whats the odd “tone” if they have heard it before. I really want to pull the head gasket to see whats behind it but keep reading horror stories of most of the bolts snapping in the process. I fear for the ones in the lower part by the cowling.
the head bolts usually don’t snap, its the water jacket bolts, and you don’t have to remove those to pull the head, but witht he age of the motor, just run it, and be thankful.