1982 johnson 140 v4 diagnosis

[TOM2000]

the engine is low on power at high revs (only 30kts @ 5000rpm on a 16ft broom aquarius) and stalls below 5 kts, the engine will also speed up or slow down by a few 100rpm by its own accord. there is also a noticable 'clunk' when you engage forward drive. Can any one shed light on what could be wrong. I want to have some knowledge before taking it to a mechanic.

 

[ddbyrd3]

Re: 1982 johnson 140 v4 diagnosis

Typically when a motor "hunts" at idel it is signifying a vacuum leak or carb problem of some sort. I would start with a complete carb rebuild using OEM kits, etc.<br /><br />As far as a clunk sound when you engage to forward, what RPM is the motor at when you engage it, and when was the last time you checked your lower end oil??

 

[ddbyrd3]

Re: 1982 johnson 140 v4 diagnosis

And Welcome to Iboats!!!!

 

[TOM2000]

Re: 1982 johnson 140 v4 diagnosis

thanks for the info.

 

[R.Johnson]

Re: 1982 johnson 140 v4 diagnosis

Start with a compression test. You have to determine if the engine is sound before replacing parts.