5.0 omc GREAT RPMS AT FIRST wants to stall after 5 min on lake

[carver 3396]

well it is a 1994 efi omc 5.0 in a 19ft four winds boat runs great at first all the way up to 4000 rps holds there on lake for about 4 min. then wants to die can keep running if you keep the gas to it near 900 rpms but really wants to cut off got back to dock and would not stay running . i let sit and an hour later started rite up same thing great rpms at first then dies ,.
here is what i have done
new fuel pumps
new cap
new fuel filter
new coil
and checked plugs looked good
OK ANY IDEA WHAT IT IS

 

[Levinz11]

Re: 5.0 omc GREAT RPMS AT FIRST wants to stall after 5 min on lake

Sounds like it's starving for fuel.

-Check the fuel pick up in the tank. Clean it if its gunked up
-Check the anti siphon valve. They fail frequently...especially is the tank is dirty
-The tank may not be venting properly which creates a vacuum the pump has to fight. Make sure the vent is clear.

 

[Chuckyd973]

Re: 5.0 omc GREAT RPMS AT FIRST wants to stall after 5 min on lake

I had exact same problem. Tuned out to be clogged needle an seat in carb. All the fuel in that carb has to get passed the tiny orifices of the needle and seat. Disassemble the float bowl and check or debris.

Chuck

 

[Levinz11]

Re: 5.0 omc GREAT RPMS AT FIRST wants to stall after 5 min on lake

I had exact same problem. Tuned out to be clogged needle an seat in carb. All the fuel in that carb has to get passed the tiny orifices of the needle and seat. Disassemble the float bowl and check or debris.

Chuck

He's fuel injected.