[dpdowling]

I have a 115 yamaha v4 that was nebuilt just last year. it has about 100 hours on it. I run a 50/1 mix of oil to gas in my main tank on top of it being fuel injected as I also use the kicker motor run on the same tank an to give added lube to the engine. I was cruising at about 2500 rpm when I heard the motor suddenly start knocking. I shut it down and limped back in on the kicker. the motor starts and runs but knocks and the fly wheel lifts about 3/8" when it cranks over. I can also lift the fly wheel the same by hand. I think this could be a top main bearing. My question is do I have to pull the whole powerhead and seperate the head and crankcase to get at the bearing or is there a way I can remove the fly wheel, stator, and remove and replace the bearing. would a bad bearing allow the flywheel to lift? would it also cause any damage interally? Thanks,dpdowling

[Capt Ken]

Not the upper bearing that holds the crank down. It's the lower bearing that is fixed on the crankshaft and holds it in place via a retaining clip. If the flywheel don't move from side to side, the upper bearing is probably OK. The knock is something else and you're probably looking at a teardown.

[coolblue1152]

You know what you have to do!