73 Evinrude-135HP engine problem?

[rhittfraser]

Out on the lake Friday on my 1977 Marlin Ski boat.
Going full throttle the motor starting losing power and sounded higher in pitch.
It ran for a couple minutes at half speed, if I tried to give it more gas, it would shut off. Waited a bit, it started again but still didn't have power and died.
At this point, I took off the cover and noticed that the flywheel was not lined up with the starter. IThe fly wheel would turn, so the craftshaft is O.K. I assume, but it or the starter must of moved to get off track so to speak. The starter would hit underneath the fly wheel when the key was turned.
Last year we rebuilt one cylinder, new carb, and shaft. It seems like these symptoms are exactly what happened last year when when we broke down and discovered we had a problem in the cylinder. Does it sounds like another problem in the engine? Any help? Thanks...

 

[ezeke]

Re: 73 Evinrude-135HP engine problem?

You may have sheared the flywheel key. Take the flywheel off and make sure that the the key is in good shape; then replace and re-torque the flywheel nut to 100 to 105 foot pounds, using a reliable torque wrench.

 

[rhittfraser]

Re: 73 Evinrude-135HP engine problem?

Thanks...would that explain the motor losing power as well?

 

[McGR]

Re: 73 Evinrude-135HP engine problem?

A spun flywheel / sheared key will mess up the engine timing which will decrease power.

 

[rhittfraser]

Re: 73 Evinrude-135HP engine problem?

Thanks for the help.
Just noticed that the fly wheel was cracked and had expanded a bit.
Would a fly wheel key cause this? Or is it more serious like a crankshaft berring?

 

[tashasdaddy]

Re: 73 Evinrude-135HP engine problem?

the cause 99% of the time is improper torque on the flywheel nut.