Stalling....splutter!!

[fcartwr]

Just inherited a 1999 Evinrude 9.9 4 stroke kicker. Perfect for trolling on my 18’ Princecraft. However, at low trolling speed it works great for 20 mins, and then it splutters and stops.
I have done the following to try and fix it; replaced the impeller; inserted new spark plugs; cleaned the carbs; cleaned the fuel filter; put in a new thermostat; bought an expensive new ignition power pack module; use premium gas etc. None of this has helped. Has anyone ideas on what may be causing this or how to fix the issue. Help!!!

 

[ondarvr]

Sounds more like an air leak or fuel pump issue. If squeezing the primer bulb when it starts to die helps, then look for either of these.

Changing parts without doing any diagnostic work gets pricy.

 

[racerone]

??----Why would anyone install a new expensive module without any testing ??------Check valve clearance on this motor.------Does it run better / longer if you elevate the fuel tank or squeeze the manual fuel pump ?----Have you adjusted the mixture needle on the carburetor ?

 

[fcartwr]

The fuel is being drawn from the main tank. We have squeezed the manual fuel pump when it splutters, but it was still hard (full and drawing) and made no difference.

 

[fcartwr]

I have one spark plug cable that was cracked. I have taped it and coated it with silicone. However, the engine cuts out after 20 mins (you can almost set you watch by it). Can it be a bad cable that causes an overheating problem?