Here's a goodie: loss of power

McKenzie

Petty Officer 2nd Class
Joined
Apr 25, 2003
Messages
192
Hey, I'm having problems with my Ford 302 in my 93 Four Winns 190 Horizon. The boat was run dry last season due to a fuel gauge issue (which has been fixed). Ever since it was run dry, the boat doesn't reach its original WOT of 4200rpms. Instead, it now reaches 3500rpms max. Also, after about 45 seconds at full throttle, the engine suddenly but smoothly loses power...almost like you backed completely off the throttle. 90% of the time is stalls. It will immediately start back up without issue. All this happens very smoothly, no sputtering or backfires. Also, it only happens under load, it does fine at the dock in neutral. Here's what I've tried:<br /><br />Put on a freshly rebuilt carb off a running 302.<br /><br />Replaced fuel filter.<br /><br />Blew out carb inlet screen.<br /><br />Tried every fuel system cleaner at Napa, Walmart, and Autozone. (SNAKE OIL!!) (added to gas tank, and concentrated in a gallon of gas connected directly to the fuel pump.)<br /><br />Replace Ignition Coil (the thinking was the loss of power was too smooth for a fuel problem.)<br /><br />Unplugged ESA microswitch.<br /><br />Unplugged ESA Module.<br /><br />(Just to see if the switch or module was killing the ignition. I put them back on after a I went for a test run.)<br /><br />Any more ideas? I am going to check timing, fuel pressure at carb, monitor coil voltage during a run. Thanks for the input. McKenzie
 

sculbert

Petty Officer 2nd Class
Joined
May 22, 2004
Messages
160
Re: Here's a goodie: loss of power

I would definitly think you are exhibiting a fuel pressure issue or restriction. Do you also have a water seperator in the fuel line? IT is possible it is stopped up.
 

McKenzie

Petty Officer 2nd Class
Joined
Apr 25, 2003
Messages
192
Re: Here's a goodie: loss of power

If I remember correctly, I used an original OMC replacement filter that is also a water separator. The old one that I took off did have some water in it.
 

sculbert

Petty Officer 2nd Class
Joined
May 22, 2004
Messages
160
Re: Here's a goodie: loss of power

did you clean or replace the fuilter at the fuel pump. some of them have filters in the pump also. some have a filter at the carb as well.
 

McKenzie

Petty Officer 2nd Class
Joined
Apr 25, 2003
Messages
192
Re: Here's a goodie: loss of power

The filter I replaced is mounted to the engine right before fuel pump. The holley 2bbl appears to not have a filter, but a screen mesh that I scrubbed with carb cleaner.
 

sculbert

Petty Officer 2nd Class
Joined
May 22, 2004
Messages
160
Re: Here's a goodie: loss of power

I would do a volume test and fuel pressure test. I don't have a OMC manual to give the fule pressure. I would guess it should be 4 - 7 psi<br /><br />With some fuel in the carb disconect your fuel line and put it in a bottle and validate a steady fuel flow also.
 

McKenzie

Petty Officer 2nd Class
Joined
Apr 25, 2003
Messages
192
Re: Here's a goodie: loss of power

Good idea, I'll try that volume test tomorrow and get back with the results. In the mean time, anyone feel free to throw in ideas.
 

merc200

Seaman
Joined
Jan 24, 2004
Messages
67
Re: Here's a goodie: loss of power

Have you tried a new fuel pump? Just a thought.
 

sculbert

Petty Officer 2nd Class
Joined
May 22, 2004
Messages
160
Re: Here's a goodie: loss of power

He can do the test above and save himself the cost.
 

McKenzie

Petty Officer 2nd Class
Joined
Apr 25, 2003
Messages
192
Re: Here's a goodie: loss of power

Finally fixed! This morning I got an outboard fuel tank and hooked it up. The engine ran perfect with that. So I then took out the floor to get to the tank. The anti-siphon valve was filled with crap, looked like seaweed and plywood splinters. Cleaned out the fittings, put it back together. Thanks Merc Blues!
 

sculbert

Petty Officer 2nd Class
Joined
May 22, 2004
Messages
160
Re: Here's a goodie: loss of power

Your welcome, That is good info for me also. I dind't even think of it being that far back. Good idea on the extra tank!
 
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