Evinrude WOT issues??

[Ultrium]

I have a '89 40hp Evinrude outboard on the back of a 1648 mod v jon boat. It cranks fine, runs great through 70% throttle and then it starts to sound like its missing. If I am on really smooth water, the engine will open all the way up and I will pick up about 10mph. Whats strange is that its kind of all at once. If I am in water with much of a chop it will not open up at all. I have had the carbs rebuilt, no alarms are going off, its not over heating, plugs look great. I am at a loss on this one. Any help is appreciated.

 

[Monte1961]

Re: Evinrude WOT issues??

A couple of things you can do to narrow issue down. Have second hand onboard to help. Take and inductive timing light on the water with cowling removed. When it starts to fall on is face/missing, check for good strong strobe on the light. NOTE: Check both plugwires!. If good, have second hand squeeze primer bulb and does the miss quite or stay the same? Process of elemination. You might want to do a spark test and a compression test for piece of mind! Post results and good luck!

 

[Ultrium]

Re: Evinrude WOT issues??

Monte,

Thanks for the tips. I forgot to mention this in my previous post but I have done a compression check (135 on both cylinders) and spark check jumped the gap no problem. I'll get another hand onboard to check the other things you mentioned.

 

[Rick.]

Re: Evinrude WOT issues??

Monte,

Thanks for the tips. I forgot to mention this in my previous post but I have done a compression check (135 on both cylinders) and spark check jumped the gap no problem. I'll get another hand onboard to check the other things you mentioned.

Did you check the spark when it was acting up? That's the right time to check it. Best of luck. Rick.