PLEASE HELP I'm stumped

Okay here is the deal now I recently had this evinrude 150 rebuilt. Now the dummy who rebuilt it did a $H1TY ***** job. This is what is going on any help will be GREAT. This motor when submerged runs like crap and only when submerged. If I put the muffs of the engine it runs likes like a champ. I cant fiqure this out can someone help me or give me some advise.

Thanks
Andy

Re: PLEASE HELP I'm stumped

This is quite common actually, you can read about that on this and every other outboard repair forum on the internet...submerging the lower unit, puts backpressure on the exhaust.

What year motor we talkin bout?
Why the rebuild? Did they find & fix what caused the breakdown?

Did you call the rebuilder & talk about the condition? A reputable repair shop will test the motor in a tank with a test wheel in place of the prop, which puts the same load on the motor as if it were pushing a boat, so they never should have let it out the shop like that. It's always possible something changed since you got it home.

The thing to do in this case is a compression test & spark test first, and inspect the fuel system, all the fuel lines, etc., make sure the fuel is fresh, fuel line is holding pressure. All the spark plug leads are attached. That sort of thing.

Except you already paid somebody to do all that, they ought to do it now.

Re: PLEASE HELP I'm stumped

Its a common problem,
do a compression test to check the rebuild.
Then do a spark test, set the tester to 7/16th inch gap.It needs a bright blue spark, not yellow.

If it passes both tests, time to look for a cylinder not firing, sometimes you can detect it by a cool cyl head when all the others are warming up or spray premix fuel into each throat to see if one makes the rpm pick up.

RPM on the hose should be around 1100 rpm.

Re: PLEASE HELP I'm stumped

the dummy who rebuilt it went out of business the rings were gone on 2 pistons. So had to get it rebuilt. Carbs rebuilt running champion spark plugs had 6 helicoils put it cuz the dummy messed it up. Took it out tonite and couldnt even make it past the dock wouldnt idle and when it finally did I gave it throttle and it seemed either like it was flooding out or not gettin enough fuel and just dying. right now its at a shop in clearwater where it was being fixed just trying to fiqure this out so I dont look like a dummy

thanks
Andy

Re: PLEASE HELP I'm stumped

its a 1987 evinrude 175 bored 50 over