the boat stutters a little as RPMs move close to 1000. its happened once each trip to the lake the last few times and I haven't been behind the wheel when it happened. first time, it started to rev then died (started right back up). second time, it revved some then dropped back down very briefly then revved again and dropped again - a couple times over a few seconds. sounds like its running out of gas.. put it back in neutral then eased into the throttle and it was fine. doesn't happen at high RPMs. haven't checked anything yet - really don't know where to start. <BR> <BR>sound like anything to you guys? <BR> <BR>do fuel pumps slowly go out or fail completely <BR> <BR>Since i've had the boat, 60 hrs, hasn't had a new filter or anything done to fuel delivery system

Do you have a fuel filter?

uhh, i would assume so

Is it a skier's choice boat (late model 03 to present) they had some minor issues with the TPS (throttle position sensor) Mine had very simialr symptoms, was replaced under warranty. Ran fine at speed but would idle rough and was intermittant.

its an 86 MC w/ 351W engine.

Start with the ignition system. You can ohm check the coil and all the wires. Any corrosion and the parts get replaced. Check the distributer cap and rotor. Does your boat have points? If so replace them if they are at all burned or worn and more importantly the condenser should just be replaced. <BR> <BR>Fuel pumps of the mechanical type generally work or don't. Water in the fuel could be the culprit as could something blocking the jet(s). Always store your boat if even for a week with the full tank full so there is no room for moisture to enter with temperature changes. If you do not have a canister type fuel filter buy one and install it. They are around $40 with a mount and will help keep contaminents and water out of your carb. If you do have one replace it, and take the old one and dump it into something glass to see if there are multi layers with one being water.

Nacho asked: do fuel pumps slowly go out or fail completely <BR> <BR>I disagree with Peter's answer. Mechanical pumps will generally go through the motions of operation as they have 300 hp to make sure it happens. If the diaphragm gets torn or the input/output check valves wear out the pump output can drop and eventually go to zero but they will decline. The problem is that you don't notice the decline until it drops below the minimum level. <BR> <BR>An electric fuel pump, on the other hand, can just quit. One second it is working fine, the next second it just won't run any more. <BR> <BR>nacho's problem does sound like a fuel problem and it could be the fuel pump but it could also be a clogged fuel filter or an air leak in the line between the tank and the fuel pump. A common source for such a leak is at the fuel filter/water separator. <BR> <BR>I would certainly recommend starting with the fuel filter. Inspect it at least, and change it if you haven't replaced it in the last year. <BR> <BR>If that doesn't solve the problem then there are two approaches. If you have the test equipement you can test the pressure and deliverly of the fuel pump and verify that it is working okay. <BR> <BR>Or you can take the "shotgun" approach: take a shot and hope you hit something. Lacking the test equipment you are often better off just to start changing things until the problem goes away. <BR> <BR>Change the fuel filters. <BR> <BR>Like Peter said, the distributor is a good place to start if you have the old fashion points &amp; condenser. Coils are not very expensive and easily changed. <BR> <BR>change the fuel filters. Check to see if there is a filter screen right at the carburetor. <BR> <BR>If you have a carburated engine then the fuel pump is generally not too expensive and easy to change. Fuel injected engines often have expensive electric pumps. <BR> <BR> <BR>Did I mention changing the fuel filters? <BR> <BR> <BR>

Yes Rod you are correct in a few things and I should have elaborated further. "If the diaphragm gets torn" This will show up in the tube that goes from the fuel pump to the carb, as it will fill with gas, instead of leaking on the ground like a car would. When mechanical fuel pumps tend to go out they are very easy to diagnose. Once a mechanical pump starts to fail, they seem to be pretty consistant, unlike an electric that can be very intermittant. If in doubt put a fuel pressure gauge on it. The cheapest way is to disconnect the fuel pump outlet line and run a hose into a container. Make sure to disconnect your impellar belt, or put water to it, then crank the boat. You should get a bunch of gas out of the tube about a pint in 20 seconds. Put your hand over the end and see if it builds some pressure around 5 psi or so. Simple as that. <BR> <BR>In "my" experience a failing mechanical pump rears it's head under high RPM's and heavy load pretty consistantly. There is always the odd ball out, so do not rule any component out.

i know i don't have a fuel filter separator - will add that at some point. <BR> <BR>the boat had the points system replaced with electronic. Spoke with the service guys at the shop and its a mechanical pump. <BR> <BR>Rod - i think i'll start with the filter. anything I should worry about changing it.. priming the pump etc.. Thank for the help <BR> <BR>nacho

Keep in mind that if the fuel pump is getting weak then it may have a real tough time getting primed again. <BR> <BR>Like Pete said, disconnecting the fuel line from the carburetor and running it into a can will show you how well the fuel pump can deliever. It should be able to pump a cup of gas in just a few seconds of cranking. <BR> <BR>I want to issue my strongest warning at this point, however! <BR> <BR>Playing with the fuel system on the boat is perhaps one of the most dangerous things you can do. That operation described of pumping a cup of gas into a can will also pump a bilge full of fumes. Open the boat up as much as you can and run the blower a lot! Clean up any spilled fuel ASAP.

if you dont have a vent on your gas tank then the problem is probably that your tightening it tooo tight. same thing happend with my brand new moomba outback. you need to leave the cap "semi" loose. if its too tight and theres no vent itll run just fine at high rpms but when you shut off the motor it causes a vacum and sucks all the gas out of the motor, thus causing it to sputter and eventually die.

Justin: <BR> <BR> If your brand new Moomba Outback doesn't have a functioning vent on the gas tank you should take it back to the dealer and have them fix it! <BR> <BR>Leaving the gas cap loose so that the tank can vent is an invitation for a lot of problems. If the vent line was installed properly it would be run is such a way that water would not flow back into the tank. The filler, on the other hand, is designed to fluid into the tank. <BR> <BR>A proper tank vent will also have a flame supression screen at the opening that will prevent flame from flashing all the way into the tank. <BR> <BR>Leaving your filler cap loose is a hazard and will eventually cause you problems with water in the tank.