140 Johnson surging in neutral

[tom stern]

Motor is a 94 140 looper, just rebuilt. Starts and runs well. After running at moderate to high RPM it idles well at ~800 RPM in gear. When shifted into neutral it will surge up to 2000-2500 RPM for 30-60 seconds and then settle down to around 1000 RPM. No coughing or sneezing. Any ideas on what to look for? Thanks.

tom

 

[tom stern]

Re: 140 Johnson surging in neutral

Any ideas? I did check the timing, thinking that maybe the quick start was kicking in. But the timing was steady.

 

[wilde1j]

Re: 140 Johnson surging in neutral

Timer base may be sticking. Check that it moves easily.

 

[tom stern]

Re: 140 Johnson surging in neutral

I disconnected the throttle cable and moved the timer base back and forth a number of times. It moves freely in both directions. I also disconnected the VRO pulse line to see if there was any fuel leaking through the diaphragm. Checked out OK. I was able to get the motor to stall when spraying carb cleaner between the carbs (silencer on to prevent drops from dripping into the throat) so I think there must be an air leak.

tom