94 evinrude 105 jet 150 powerhead spitting and wont wot

[105jet94evinrude]

Have a 150 powerhead that is cold blooded to get started once going runs fine at an idle go for WOT and good till 3/4 throttle and looses power and falls on its nose.
Compression test is 75 on all cylinders plus or minus 3 points was ran with no thermostats from previouse owner possible carbon build up? Help me please!!

 

[105jet94evinrude]

Re: 94 evinrude 105 jet 150 powerhead spitting and wont wot

Does anyone have any ideas or is a rebuild needed?

 

[boobie]

Re: 94 evinrude 105 jet 150 powerhead spitting and wont wot

Sounds like a fuel problem. Also put the themos in it and do a good decarb on it.

 

[105jet94evinrude]

Re: 94 evinrude 105 jet 150 powerhead spitting and wont wot

Put thermos in and decarbed it, replaced all fuel lines and filters, fixed leak on plastic carbs, and I was running ngk plugs equivalant to the champions and that motor did not like it. Put the champions back in and ran alot better at idle but still falls on nose at wot. Maybe a rebuild but I figured it would be alright seeing how there all even. I put some of that bombardier tune through it and it is suppose to remove carbon in the motor and hopefully bring up compression. Not sure how that stuff works but I will re-do a compression check tonight. The next thing that I can think of is a power pack, maybe its not getting enough voltage to run the ngk and the champions take less?? Im kinda at a dead end right now and need some ideas I'm not too familiar with the evinrude family so I'm piecing as a I go just from prior merc experience!

 

[boobie]

Re: 94 evinrude 105 jet 150 powerhead spitting and wont wot

Take the air box cover off, get a squirt can with premix in it, and have somebody else run the boat. When it wants to fall on it's face squirt some fuel in each carb throat and see if it picks up. If it does you have a fuel supply or carb prob.

 

[105jet94evinrude]

Re: 94 evinrude 105 jet 150 powerhead spitting and wont wot

Have tried that already I think maybe that my timing is advancing to far when opened all the way up its got that timing deal on top of the motor if you are familiar with that and i think that when i ask for wot it advances too far or falls off the deal and that is whats causing that. any ideas on how that works or where its suppose to be?