WOT loss of power

[2cycle]

Greetings (I'm new to the board). I have a 75 Inline Merc 150 HP that runs well out of the hole and onto plane, but stalls at or around WOT (5000-5500 RPMs). Sometimes it will run well for several minutes but invariably stalls. I have a new built in tank, primer bulb and Tempo inline filter. Is the fuel pump or vacuum leak the most likely culprit, or is there something I'm missing?<br />Thanks in advance for responses.

 

[mellowyellow]

Re: WOT loss of power

try squeezing the primer bulb next time it starts<br />to lose power. if it picks back up it's fuel<br />starvation. if you squeeze the primer bulb and<br />see fuel running outa front of carbs, the float<br />is sticking and she's flooding.<br />my guess is an air leak somewhere in system.<br />sucking air, not gas. time for a carb rebuild and<br />new fuel pump diaphrams if hasn't been done for<br />awhile.<br />good luck,<br />M.Y.

 

[Clams Canino]

Re: WOT loss of power

Also, try running it without the inline filter and after cleaning the filter that's built into the fuel pump. Just to be sure.<br /><br />-W

 

[KCLOST]

Re: WOT loss of power

Are you sure the tank is vented? (or venting properly)

 

[2cycle]

Re: WOT loss of power

Thank you all for the helpful advice. That definitely helps me to narrow it down. The tank should be venting properly but I will double check the vent outlet on the side of the boat and recheck all connections between tank and fuel pump. Will also remove inline filter and also run with remote tank to see if problem may be in fuel line or bulb. I also installed an anti-siphon valve new with tank. Does or will this create significantly more drag than a simple 3/8 barb?

 

[2cycle]

Re: WOT loss of power

Update: I replaced fuel pump and then happened to run the boat at night on the hose. When I did so, I noticed an intermittent arc from the # 2 plug as the plastic casing had somehow developed a crack. Hope this solves it also with fuel systmem checks and maintainence. Thanks for help.