1989 Evinrude 40 HP (E40TLCE) Outboard Wide Open Throttle (WOT) Surging

As the thread title reads, I'm having issues with my 1989 Evinrude 40 HP (E40TLCE) outboard surging at WOT. I've linked to a YouTube video I just created to demonstrate the surging.

https://youtu.be/_BoOClBmZI0

The surging starts at https://youtu.be/_BoOClBmZI0?t=75

From what I've read on various boating forums, likely culprits could be a clogged main jet in one or both of the carbs, failing VRO pump or failing power pack.

I should note that pumping the fuel primer bulb while it's surging has no effect and pushing the key in to active the primer solenoid and flood the carbs with fuel has no effect.

Just curious if anyone else here has had similiar issues with a motor and could provide some guidance as to what might be happening and where I should start. I'm no stranger to engines as I've done a fair bit of diagnostics/wrenching on my own vehicles, tractors and tons of small 2-cycle engines; however, this is my first outboard so I'm a bit out of my element with troubleshooting/diagnostics.

Any help/guidance is certainly appreciated!

-Tom

Why are you rynning WOT with no load ?

racerone said:

Why are you rynning WOT with no load ?

Click to expand...

I'm guessing from your response, running at WOT without a load is bad. If so, good to know and duly noted! Like I said, this is my first outboard so I'm learning as I go. Is it safe to assume what I'm seeing is the engine hitting a rev limiter, which prevents a run-away/over rev condition? I'm also assuming there's a certain amount of back pressure required, which would be missing if run when out of water.

Thanks for your time!