2003 Johnson 115 4 Stroke sputtering at high RPMs

[ericl11]

I have an 03 Johnson 115 4s. Starts fine and idles fine will even go WOT fine for a while then starts sputtering. It will not shut off but continue to sputter. I can bring it back to idle and open it up a little and may or may not sputter right away.

What could be the problem? Where do I start?

 

[ericl11]

Re: 2003 Johnson 115 4 Stroke sputtering at high RPMs

Took it out today to try to pinpoint where it is happening. It appears that I have no issues up to 22 MPH (tach broken also but should be apprx 3000 rpms) anything above that it appears to starve for gas but not consistently. When it happens I can lay off the throttle back to 20 mph and back to OK. I can give it a little more throttle and it may sputter right away or it might take 2-3 minutes, inconsistent.

Engine has 300 hours.

 

[CharlieB]

Re: 2003 Johnson 115 4 Stroke sputtering at high RPMs

300 hours, any maint done?

First thing I'd do is look at the spark plugs, and tell us what they look like.

They should be alight to moderate tan in color, no accumulation of deposits, the edges of the electrodes clear and not melted/misformed and a gap still within spec for your year/model, which should be listed on your engines data plate.

Poor spark plugs will allow an engine to start and perform up to near peak RPM, but begin to fail as the engine nears maximum load.

 

[kenmyfam]

Re: 2003 Johnson 115 4 Stroke sputtering at high RPMs

How abot a carb service ??? could be a restriction somewhere.

 

[ezeke]

Re: 2003 Johnson 115 4 Stroke sputtering at high RPMs

I would start back at the beginning, looking for an air leak.

 

[ericl11]

Re: 2003 Johnson 115 4 Stroke sputtering at high RPMs

Service done at each 100 hr interval. Actually this happened first trip after maintenance at 300 hours.

 

[johnboyj]

Re: 2003 Johnson 115 4 Stroke sputtering at high RPMs

Don't for get to look at the fuel filter, may be getting clogged. Or your primer bulb may be faulty loosing its prime. The one-way valve on the inside may not be closing anymore