15 hp merc. fuel pump?

[fishnhunt2]

i have a 1999 15 hp merc. that cuts out and seems to be starved for fuel at wide open throtle. runs great otherwise. fuel sight bowl is less than full when engine sputters at wot. i have changed the fuel line bulb thinking that might be the problem, but it wasnt. also checked the fuel filter, and it seems fine. what should i check next??? thanks!

 

[bubbakat]

Re: 15 hp merc. fuel pump?

ck the little o rings that are in the female connectors in the fuel lines,and the diaphragm in the fuel pump

 

[rickdb1boat]

Re: 15 hp merc. fuel pump?

Make sure your fuel tank vent is open and clear. Run without the fuel cap and see what happens. If you pump the bulb when this happens at full throttle, does it run fine? Is the bulb staying firm? Is this an Merc brand bulb, fuel line or generic? It does make a difference!

 

[fishnhunt2]

Re: 15 hp merc. fuel pump?

ok, tried running with the tank cap off, still had the same problem. fuel line connector ends look good. the bulb does not stay hard when running. how would i know if the fuel pump is bad?

 

[fishnhunt2]

Re: 15 hp merc. fuel pump?

ok, tried running with the tank cap off, still had the same problem. fuel line connector ends look good. the bulb does not stay hard when running. how would i know if the fuel pump is bad?

 

[Elmer Fudge]

Re: 15 hp merc. fuel pump?

It looks to me like a fuel pump rebuild is in order,a fuel pump kit is inexpensive and it's an easy job to do yourself.

 

[JoeW]

Re: 15 hp merc. fuel pump?

I had the same thing happen to me on a 100 hp Merc outboard. I couldn't find the problem, but my mechanic did. It was a hairline crack running lengthwise in the fuel line on the transom side where I couldn't see it.

 

[rickdb1boat]

Re: 15 hp merc. fuel pump?

I look at it this way, if the bulb is going flat, something is sucking it flat. That something is the fuel pump. It could be weak, but the bulb should still stay firm. It would have to be from the bulb to the fuel tank. The fitting at the engine is probably good. The bulb may have a bad check valve, even though it's new. Could be a bad fitting on the tank. Could be a bad or partially clogged fuel pick-up filter in the tank. Pick-up tube in the tank could have a crack in it. Try a different tank and see what happens, first. If you can pump the bulb at all when this running problem occurs and it picks back up, then I would head for the pump. Also, does the bulb ever pump up firm? As in at the start of the day?