Motor Vibration

[wilson973]

I have a 1989 Johnson 70hp. Today when I took it out the motor started vibrating really bad. After I left the landing I started to plane out and about a minute later the motor started vibrating really bad. I slowed down and it was a very slight vibration. If I got over 7 mph it would vibrate really bad. It starts up just fine and idles just fine. Any ideas?

 

[Skagit Hunter]

Re: Motor Vibration

bent prop broken motor mount?

 

[Bifflefan]

Re: Motor Vibration

Check the prop, and the spark plugs.

 

[5150abf]

Re: Motor Vibration

put the engine in nuetral and slowly turn the prop and look for a bent prop shaft, maybe use a screw driver or something off the vent plate as a gauge.

Is this an engine you have had for awhile and this is a new problem?

Have you hit anything in the water recently, this doesn't sound like a problem that would just happen unless it is a cylinder out but if it idles and runs normally that probably isn't the case but a spark and compression check cetainly won't hurt.