1994 Johnson 140hp V4 low rpm vibration

[wendhall]

I purchased a 1994 Seaswirl Striper with a 140 hp Johnson V4 engine in March. This is my first boat purchase. The engine starts and runs well except during low speed operation it vibrates in/out of the water with the prop engaged or not engaged. I replaced the plugs and plug wires and cleaned the coil connections, checked the recircs for pluggage and good fit, treated and removed as much of the fuel/replenished, with no results and am now looking for any suggestions prior to taking to the local Johnson repair shop. I will attempt to rebuild the carburetors before the repair shop but am now seeking any advice prior to the repair shop visit.

Thanks
Wendhall

 

[tashasdaddy]

Re: 1994 Johnson 140hp V4 low rpm vibration

start motor on muffs, remove one spark plug wire at a time, be aware of any change in the idle, if no change that cylinder probably is not firing. have you done a compression check. post results.

 

[wendhall]

Re: 1994 Johnson 140hp V4 low rpm vibration

start motor on muffs, remove one spark plug wire at a time, be aware of any change in the idle, if no change that cylinder probably is not firing. have you done a compression check. post results.

Compression check was done in March just after purchase. Thank you

 

[kenmyfam]

Re: 1994 Johnson 140hp V4 low rpm vibration

Compression check was done in March just after purchase. Thank you

Welcome to iboats. You should post your compression results and do as Tashasdaddy suggests with the plugs. That is a great starting point to solving your problem.