running hot or fuel flow, which one

JESSIELSMALL

Petty Officer 2nd Class
Joined
Mar 15, 2006
Messages
112
I can run top speed for about a mile when a continuous buzz comes on. when I slow it down the engine cuts off and the buzz remains until I turn the key off then the buzz stops. my primer bulb has also been going soft, one time it was sucked flat. if this makes any sense can some one help. I forgot to mention, the boat runs top speed with the buzz until I throttle it down. I never ran it more than sixty seconds after the buzz started to see if it would slow down on its own.
 

wilde1j

Vice Admiral
Joined
Apr 15, 2002
Messages
5,964
Re: running hot or fuel flow, which one

Continuous = HOT, STOP
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: running hot or fuel flow, which one

Primer bulb drawn flat = Fuel restriction.

(Fuel Anti Siphon Valve)
(J. Reeves)

Many of the later OMC V/6 engines incorporate a fuel restriction warning via a vacuum device attached to the powerhead. If the engine overheats, or if you have a fuel restriction, the warning is the same.... a steady constant beep.

NOTE... Only the V/6 & V/8 engines have the above "Fuel Restriction Warning". The warning horn will not sound on the other models.

The fact that a engine is not overheating, but the warning horn sounds off with a constant steady beep, and that the rpms drop drastically would indicate that the engine is starving for fuel due to a fuel restriction. Check the built in fuel tank where the rubber fuel line attaches to the tank fitting. That fitting is in all probability a "Anti Siphon" valve which is notorious for sticking in a semi closed position. It will be aluminum, about 2" long, and the insides of it will consist of a spring, a ball, and a ball seat. If this valve exists, remove it, knock out those inner components which will convert it to a straight through fitting, then re-install it. Hopefully that cures the problem.

The above procedure will cure a restriction problem with the anti siphon valve as stated. BUT, it may also allow fuel to drain backwards to the fuel tank when the engine is not running (siphoning backwards) due to the fact that the carburetors/fuel pump etc are higher than the fuel tank. This condition is not an absolute as the valves in the fuel primer bulb usually prevent this backwards siphoning problem. However.... if this does take place, the cure would be to install a new anti siphon valve.
 
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