1992 evinrude 15hp weird symptoms

[trihullfisher]

What's up every one ..I've searched long and hard and can't really figure this thing out. So cold start with choke it fires on 2nd or third pull and will idle all day and throttle nice in neutral. When on the lake and in gear and will work for maybe 30 secs then die. Now if that's all it did its a pretty easy fix...but fast forward about 10 mins of letting it idle and playing with the throttle she goes perfect. But it feels like it's running on one cylinder or is misfiring chugging . So far it has new plugs and wires .also a brand new fuel connector .havnt looked at the fuel pump or lines on the engine because like I said once it's fully warmed up after dying a couple times it goes pretty nice ..I can do about 20mph on my 14ft trihull

 

[racerone]

Have you installed a new water pump impeller ?-----Install a new diaphragm in the fuel pump.----When it is acting up pull the top wire off the sparkplug.---Will it start on the bottom cylinder ?----Repeat the test by pulling wire off the bottom cylinder.

 

[OptsyEagle]

Perhaps it is the fuel line. I had one that always worked perfectly in the mornings, with cool weather, but after a while with the warm sun it failed. I suspect the check valves in the primer somehow would get stuck. Priming the bulb worked OK but it would not move fuel automatically. I say this because 30 seconds is about how long the gas in your carb would last if gas is not pumping through automatically after you primed it.

The only test would be if you have the symtoms again, try sqeezing the primer bulb quickly, as it starts to die, and see if that revives it. If it does not then the problem is elsewhere and if it does it is a fuel pumping problem and most likely the line if it is acting like you say.

Just my thoughts and the experience I had once.

 

[racerone]

Run with a timing light.----One cylinder at a time.-----When you think it is running on one cylinder , ----Should help you figure out which cylinder might not be firing.