Barnowl

My Feedback: (2)

I have a four stroke Magnum 61 which has virtually quit running. It first started surging while at max rpm; putting pressure on the top of the needle valve stopped the surging, so I assumed an air leak and tried putting fuel tubing around the base of the needle valve. When turning up the engine to test, after running about a minute at high rpm the engine made a strange squeaking sound and stopped dead. When I tried to restart, it would start, run for maybe a second and quit immediately--no missing, popping, or gurgling, just that squeaking sound and silence. Any ideas? I checked the valves and they are slightly loose but they are within tolerance; I don't have a way of checking compression, but it does seem low but I'm really not sure.

Thanks!!

w8ye

My Feedback: (16)

Sounds like you may have lost the rear main bearing? The bearing cage can tear up and the engine will turn over by hand with no suspicion but when you run the engine, all the balls will go to one side and lock the engine up.

Take off the back plate and examine the rear bearing very carefully with a strong flashlight. Look for the cage to be gone from the bearing balls?

Enjoy,

Jim

mentorman

My Feedback: (2)

contact hobby people/ global services they will fix it.

Flyboy Dave

My Feedback: (21)

Pull the valve cover and check all the head bolts, then re-check the valves.
If the valve adjustment has changed, that's a good indicator that perhaps
the screws were loose, and it could have had an air leak.

FBD.