Nissan motor makes a put put noise for 4 seconds after I shut it off

[joseph35]

My boat motor makes a put put noise for about 4 seconds after I shut it off. Any idea what the cause could be? When I take the cover off the motor, I can see and smell/see a gas leak comming from the spark plug area.

Nissan: 40 hp
model: NS40C
year: 1992
Serial: 67822
Tiller

 

[Sea Rider]

Re: Nissan motor makes a put put noise for 4 seconds after I shut it off

With engine off in neutral, spin the prop, do you hear that noise, Check that both plugs are adjusted tight too. If both OK, probably head gasket or base head gasket is worn and/or out of correct torque and leaking compression somewhere.

Happy Boating

 

[nwcove]

Re: Nissan motor makes a put put noise for 4 seconds after I shut it off

you may need to do a decarb on it......4 seconds of "put put" sounds like "run on"....which is a classic sign of a carboned up motor.