1998 Force 120 - fuel feed / stalling problems

[Cooperman]

I run this engine from new on a 98 Maxum 1700xc and it is strong and reliable but has always had the (usual?) problems of poor idling. All has been fully maintained and is ok. When tested with an external 4 gallon fuel tank it idles perfectly, when connected to the 21 gallon internal tank it stutters and stalls (even when not fully trimmed in (recommended by mechanic)) as though it is not getting adequate fuel supply. Bulb also runs 'soft'. Any ideas much appreciated, also does anyone know if there is an electric fuel pump and or autolube system available for this engine?<br /><br />best regards<br />Cooperman

 

[LubeDude]

Re: 1998 Force 120 - fuel feed / stalling problems

Sound to me that the vent tube on the built in tank may be pluged with something. Try it with the gas fill cap removed or losened a bit. Could be bad fuel in the main tank also. Do you have a water separating fuel filter on the main tank? You should.

 

[roscoe]

Re: 1998 Force 120 - fuel feed / stalling problems

Try what Lubedude says. <br /><br />If it heolps, then clean out the vent line, bugs like to get in there an build a nest.<br /><br />If the bulb still goes flat, replace the fuel line.

 

[199675hpforce]

Re: 1998 Force 120 - fuel feed / stalling problems

i think its the fuel pump diaphram need rebuild its easy and cheap to do $20. Mine is having the same problems changed mine out but did not follow the instructions by snaping the plastic retainers in the valves. Guess i will try a new one

 

[Cooperman]

Re: 1998 Force 120 - fuel feed / stalling problems

Guys, this is excellent advice, many thanks. I have had the boatyard rebuild the fuel pump and that got it running really well on the external fuel tank; and I did completely renew the fuel pipes etc last summer and checked the breather was clear, but I think I will check the breather again and also rebuild the pump again fully. The water seperator / fuel filter seems fine and is changed at the start of each season - about to be done again as part of the full pre-season service.<br />Any body tried an electric fuel pump? I wonder if I can use an automobile one and if that would overpower the floats / valves in the carbs?

 

[outboardguy]

Re: 1998 Force 120 - fuel feed / stalling problems

Generally the major problem is the anti syphon valve at the gas tank.The fuel pump is pulse driven off of the engine and is not real strong and with the added restriction of the anti syphon valve it sometimes just runs out of fuel. Being that your tank is built in you can not just remove the valve and replace it with a straight fitting for safety reasons. But you could remove it and see how much suction it takes to get it to work.Just put the barbed end to your mouth and suck.If it is real hard you may be able to adjust it.Look at the threaded end and you will see a ball bearing being held in by a sleeve.Mount valve in vice and use a punch from the barbed side and gently tap the ball until the sleeve moves a bit.When you're done it should be easier to suck through and you shouldn't be able to blow through it.

 

[Excalibur222]

Re: 1998 Force 120 - fuel feed / stalling problems

I had the same trouble on my force 120 and after much head scratching etc, found the fuel pump had a cracked gasket between the sections that was not visible until I took it apart. Bought a pump rebuild kit, installed it in about 10 minutes, and intantly ended the soft primer bulb, poor idle problems. ( Mine also idled okay on an external fuel source ) apparently the built in tank required more suction that the pump could put out with the cracked gasket.