OMC Full Throttle fuel pump? problem

[rboat99]

I have an 89 OMC 140 Seadrive. When I have the throttle wide open the engine it runs good for a couple of minutes but then the engine hesitates, the RPMs drop by about 1000 and then return. This drop and return in RPM continues until I lower the throttle or have someone pump the primer bulb. If no one pumps the primer bulb and I return to full throttle it continues to act up and does not top out at the same RPM. I replaced the primer bulb to no avail.<br /><br />So my question is, does this sound like a fuel pump problem or what?<br /><br />On an unrelated not I do not seem to be getting good charge from the charging system. When running it does not go higher than about 10 volts.

 

[Jquest]

Re: OMC Full Throttle fuel pump? problem

YOu might have an air leak somewhere. You should start looking at the engine where the gas line is connected and work your way back to the fuel tank. pull and turn the connections gently and see if something is loose. If you have an air leak...the engine might be starving at full throttle.

 

[truax42]

Re: OMC Full Throttle fuel pump? problem

I had the same problem on my 89 120 v4 Evinrude. I thought air leak also but it turned out to be the fuel pump. <br /><br />I am also having the same charging problem but I can get almost 12volts when running. Hopefully someone can get us pointed in the right direction on the charging

 

[Bass Runner]

Re: OMC Full Throttle fuel pump? problem

I had this problem on a 85hp and it was the screen plugging up on the pickup tube in the tank, took it out cleaned the screen and washed the tank out with clean gas and no more problem, gads i replaced the pump and all the fuel lines before an old hand told me to check it, also might be the vent plugging up.

 

[rboat99]

Re: OMC Full Throttle fuel pump? problem

I read on another forum that someone could try a portable gas tank, and just connect it to the inlet port on the engine itself thus bypassing all of the hoses, primer bulb, water separator, tank, VRO(currently disconnected anyway), etc. If the symptoms disappear then my problem would be in one of the components I bypassed.<br /><br />Have not looked at the inlet port size/location so I do not know how difficult this might be, but it sounds like a good place to start.

 

[james roach]

Re: OMC Full Throttle fuel pump? problem

feul pump

 

[rboat99]

Re: OMC Full Throttle fuel pump? problem

James, is that a vote for the fuel pump being my problem? Can you elaborate?