Oil problem with 90HP 2 stroke

[wrangellwags]

I recently purchased a rebuilt mid 90's 90hp 2 stroke from a shop. Put 9.7gallons of gas through it the first day it was in use. I was just about done for the day, I was at about 25% throttle and it dies, It started right back up but it sounded like the starter was really laboring to turn it over. I knew it wasn't the battery. I took the cowling off and noticed that very little oil had been used (maybe 6-8 ounces). Pulled the plugs out and turned the flywheel over by hand, the cylinders were noticeably rough and a little stiff. I put some oil in the cylinders and mixed up some gas about 40:1, I then disconnected the oil pump drive shaft and plugged the right hoses. I have been running the outboard for about a week now and have put about 30 gallons of gas through it at a 50:1 ratio. The cylinders feel smooth. I think I'll just premix from now on.

Now for the questions:
1) Do you think the bearings are damaged and it's just a matter of time until they go, or should I just keep running it.
2) Is there a way to inspect for bearing wear without a complete tear down? How about inspecting the rings and cylinders?
3) Any idea why the motor shut down in the first place even though it wasn't entirely seized up?

I really need for this to be a dependable motor. I use it in a remote location in Alaska, otherwise I'd just keep running it till it "blows up".
Thanks, Mark

[robert graham]

I have the same motor only mine is a C model(premix). Maybe you can use a Bore Scope and look into spark plug holes to inspect the cylinder walls for grooves or scratches. If cylinders are smooth and motor is running O.K. then the bearings and all are probably fine. For simplicity and dependability I much prefer the premix, and sounds like for your remote running purposes in Alaska the premix would be the best. Good Luck!

[robert graham]

A couple of other items for your remote running: remove,check,clean,grease and tighten all electrical connections, battery cables, connection on starter, ground wires,etc., and replace the water pump impellar...not that tough of a job, and you can buy the entire water pump kit for about $50 on line. I understand you need that motor to run to get you home! Good Luck!