Motor not getting fuel

[aeviaanah]

I just rebuilt a 1962 15hp Sea King, very similar to Johnson/evinrudes.

After pumping primer bulb motor runs great until it loses fuel. I need to squeeze the primer bulb a few times to keep it going. I can hear bowl in carb filling up with fuel during priming.

Things I've done to help narrow problem...
-Used two separate fuel tanks, primer bulbs and fuel lines, new connectors as well.
-Cleaned carb, retested then rebuilt and cleaned carb again. There are no adjustments to be made inside the carb right? All adjustments come from high and low speed knobs? The float needle had a brass/bronze threaded coupler that I assumed was just a housing for the needle. I just hand tightened it, everything else is properly assembled according to parts diagram
-Cleaned fuel pump twice including fuel filter
-Disconnected fuel pump fuel out line while motor was running fuel was pulsating out. Not sure if it's a weak fuel pump or not.
-Tightened all fuel hose collars to ensure no air leaks.

So far I'm leaning towards fuel pump any ideas how to test it?

 

[lindy46]

Re: Motor not getting fuel

Did you install a carb rebuild kit or just clean it? If the motor keeps running if you squeeze the primer bulb, it sounds like a fuel pump issue, but you say the pump pulses fuel when you disconnect it? Hmm.

 

[kbait]

Re: Motor not getting fuel

Does your motor have a fuel filter between the pump and carb.. usually contained in a glass sediment bowl? If so, remove filter from bowl and try again. I've seen 'em semi-clogged to where you could push the fuel through with the primer bulb, but the pump itself couldn't overcome the resistance due to the clog, and not feed the carb correctly. If it works w/filter removed, you need to replace. Try Tim's 218-682-2331 w/your motors model number.. they usually have exactly what I'm looking for. Good luck!

 

[tmcalavy]

Re: Motor not getting fuel

fuel pump diaphragm is probably bad...replace it with stock pump or a mikuni pump.

 

[aeviaanah]

Re: Motor not getting fuel

Did you install a carb rebuild kit or just clean it? If the motor keeps running if you squeeze the primer bulb, it sounds like a fuel pump issue, but you say the pump pulses fuel when you disconnect it? Hmm.

I cleaned and replaced parts inside - float, valve packing, float gasket. Bowl to carb gasket was still good. The fuel does pulse as its coming out of pump.

Does your motor have a fuel filter between the pump and carb.. usually contained in a glass sediment bowl? If so, remove filter from bowl and try again. I've seen 'em semi-clogged to where you could push the fuel through with the primer bulb, but the pump itself couldn't overcome the resistance due to the clog, and not feed the carb correctly. If it works w/filter removed, you need to replace. Try Tim's 218-682-2331 w/your motors model number.. they usually have exactly what I'm looking for. Good luck!

Fuel filter is in fuel pump and it is clean, no filter in carb.

fuel pump diaphragm is probably bad...replace it with stock pump or a mikuni pump.

That's what I'm thinking...

 

[aeviaanah]

Re: Motor not getting fuel

I think I may have figured it out....I connected fuel tank line directly to fuel pump and it ran fine.

Its not the fuel pump, Its the fuel line before the fuel pump and after the fuel quick disconnect fitting...that or the quick disconnect fitting itself which i doubt...I held my finger over the quick disconnect fuel out port and squeezed primer bulb, it holds with no leaks. The line i have on there now is 3/8" ID and the fuel line before quick disconnect (from tank with primer bulb) is 5/16". Im thinking as the diameter steps up it creates a loss of flow or an airlock or something.

Ill purchase some 5/16 fuel line tomorrow.

 

[Willyclay]

Re: Motor not getting fuel

Attaboy!

 

[jim j geezer]

Re: Motor not getting fuel

nope.

More likely than not, either the male or the female "quick connect" is leaking air into the fuel circuit.
The tipoff was when you said you could squeeze the primer bulb to keep it running.
The female "quick connect" has an "O" ring that's prone to wearing and becoming misshapen.
Good luck.
Jim J Geezer.

 

[jim j geezer]

Re: Motor not getting fuel

1st... I misspoke.

I should NOT have begun with, "nope". <--sounds too combative and tends to dismiss previous suggestions. My bad.
Should have gone with something like: "Here's a thought."

2nd... I just remembered that the OMC external tank's fuel line likely has TWO quick disconnects - one at the tank and one to the engine. A while back I happened across a "how to" to service the quick disconnect on the external tank. Alas! I diddle bookmark it.
While you're squeezing the primer bulb, look for fuel leaking from either of the quick disconnects. If fuel can leak out, air can leak in.
Good luck.
Jim J Geezer