Fuel Pump problem?

Boat: Malibu wakesetter VLX with '03 Indmar Monsoon 335 EFI engine

Late last season my boat started to cut out while wakeboarding and loaded. I wouldn't go past 11mph and would sputter if I pushed the throttle forward. I could turn off the boat and bring it up to 25mph for about 3-4 minutes then it would start cutting out and go back down to 11mph. The 1st time I took it to the shop they cleaned a fuel strainer that had some sand in it they said. That fixed it for about a month. I took it back and they replaced the fuel filter (didn't have the part my previous visit or would've done it then) and then the season was over, after about 1 month's use this year the same problem is occurring. Does anyone have any troubleshooting ideas, possible candidates, or suggestions as to what might fix or temporarily remedy the situation? The boat only has about 350 hours on it, I'm the original owner, only been in lake water and it's been taken care of pretty well w/o any big problems.

By Karl De Looff (boarditup) on Tuesday, July 28, 2009 - 10:52 am:

Likely the fuel line is gummy from alcohol in the gasoline. Replace the fuel lines and this will likely take care of the problem.

I posted above about 2 years ago and am still having the same problems. Not sure if it's electrical, fuel pump, or what. It used to only occur with under 1/2 tank and under load of towing with ballast. Now it started happening with 4/5 of a tank and under no load and it's driving my crazy. Had 2 different mechanics check it at 3 different times and still no luck!! I'm not sure about replacing the fuel lines or how much that may cost. I can change the oil and winterize the boat myself but I haven't tried much more but willing to learn. I've also saw some similar threads saying fuel pumps are being replaced now after 4 years due to ethanol in the gas.

Ive got a 2004 supra and my boat would sputter under a load and it was my fuel pump.

Try fuel medic. It's cheap and easy to try. If you have gum in your lines, it might clear it out.

My 2002 supra was doing something similar. It would run for 1-2 minutes perfict then shut down and would not go over 3-4 mph. I could cut the boat off and let sit for a couple of minutes and the same process would repeat. I changed fuel filter and low pressure fuel pump (mine has 2 pumps) and it did the same thing. I finially figured out it was a clogged strainer on my main water intake and it was causing the boat to overheat and go into "limp mode" you may check to see if overheating is your issue and then check yor impeller and any strainers on the water line. It took me literally 4 months to figure this out. Good luck...hope its something simple

Have you put a fuel pressure gauge on the fuel rail to find out what your fuel pressure is?
How does your cap and rotor look? Any corrosion inside causing weak spark?
Ethanol is not good for spark plugs. When was the last time they were replaced?
Ethanol is also not good for injectors. I know of a boat shop that is doing lots of injector cleanings over the last few years. The 10 years prior only 2.
I imagine the mechanics have hooked up the computer to the engine to pull any codes that might be there and test the individual sensors and injectors?

I'll look into fuel medic and try that. I was thinking about buying a bunch of sta-bil and using 2 everytime I filled up to see if it would clean the tank.

The mechanic said the pressure was OK. Not sure what to check for the cap and rotor, never replcaed the spark plugs. I used fuel injector cleaner bottles (2) and added to the tank last week and problem still occured. I can use the boat about 1 hour before this starts to happen.

There are no codes that are displayed when a mechanic checked it and no signs of overheating on the temperature guage and I know that guage is working. My mechanic also hooked up a seperate fuel supply and could not reproduce the problem so I don't think it's anything outside the fuel system. I want to troubleshoot before I take back to a mechanic since I've spent about 1200 on the problem diagnosing it and believe to have fixed it and never a true fix. Also the only part that was replaced during that diagnosis over 3 seperate visits to 2 mechanics was a fuel filter change.

Some possibilities I think from reading forums are:

• Fuel pump going bad (one time my gas guage wasn't working and I completely dried out the tank, I heard with EFI drying out the tank can kill the fuel pump)
• Fuel screens, I've seen there are 2 but not sure where and how to check
• Bad gas or crap in the tank that would cause lines to clog, gum up, screens to clog, etc since It goes away for a while after I fill the tank up to full.
• Crimped or block fuel vent line

I have an 03vlx too. Fuel probs this weekend. I would definitely check your fuel pressure at the fuel rail. That will tell you immediately if that is the issue. From there it could be any of fuel pump, lines, filter, etc... I am no expert at all, but that is what I am trying (i haven't resolved it yet) My troubleshooting method is always cost driven...i.e. cheapest possible solution first.

Don't use ethanol fuel. Do what you have to to find non-ethanol. The older boats like ours arent set up to run it.

It sounds like each time you've replaced the filter, the prob has gone away, only to return later. Change the filter again and put in a fuel stabilizer. I had that problem last year. Boat had no power. Wouldn't plane out with a boarder behind it. Changed the filter, took care of the problem. Soon after, problem resurfaced. Added a fuel stabilizer and replaced the filter again. Took care of the problem.

I added Marine Grade Sta-Bil to a full tank this weekend, ran it for about an hour and ran into the problem. I stopped for about an hour and then ran the tank dry between doing sets and cruising around over the next day and didn't experience the problem. I added some Gum product (cleans fuel system) on a near empty tank and filled up to full and have not encountered the problem yet (used 1/4 tank). So I think my plan will be to keep using the marine grade fuel stabilizer with every fill and occasionally use the fuel cleaner system and see what happens over the next few weeks. I'm also using the cost driven method and will wait and see. Also, my wedge screws sheered off during a set and curled my wegde plate all to 1 side, so I got that going for me with costs as well. That actaully happened a year after I got the boat and had it fixed under warranty.

BTW, my issue was not fuel related. A sensor had come unhooked near the oil filter(oil pressure Sensor???) and once reconnected ran great. My fuel pressure was about 34 psi and after filter replacement and fuel pump screen cleaning, 38 psi. Unfortunately someone who will remain unnamed left something on over the weekend and killed my remaining battery. Not too dignified having my vlx towed in with a brand spanking new 2011 SAN 210 (our freinds boat)...They even posted my demise on facebook for all to see....just to rub it in.