Update :Help me diagnose this.

[OLDGUY]

OK I have new plugs, new cap and rotor, new fuel filters (2). Now the problem. I can go out and pull a skier at 32 mph or a foil or a wake boarder at 22 mph and it runs fine at first. Later on in the day it will start cutting out when pulling someone. The engine sounds like its starving for fuel. If you have ever run out of gas. The way the engine starts acting are the same symptoms. I can pull the power and wait a few moments and it will run right but will start sputtering again in a few minutes.

Does a fuel pump go out gradually or quit all at once? By the way I pulled the gas tank out cleaned it out to make sure there was no garbage in the tank. I unhooked the fuel line from the fuel pump to see if the screen in there was clogged. But mine doesn't seem to have one (read about the screen in another post). And before one of you ask the gas tank is completely topped off when I go out and its probably about 10 to 15 gallons down when it acts up. This has been going on for several weeks and the problem gets worse each trip. Any ideas anyone?

Edited September 4, 2010 by OLDGUY

[Pistol Pete]

If you can, the first thing I'd do is put a fuel pressure gauge on it next time out. They can be had pretty cheap at an auto parts store. Tap into the fuel line here...

You should have 35-47 psi.

edit, BTW, was this problem there before or after you replaced all those parts?

Edited July 25, 2010 by Pistol Pete

[OLDGUY]

Thanks for the reply Pete it was starting to do this before I changed the parts. But now it is getting progressively worse with each trip to the water.

[OLDGUY]

I will get a fuel pressure guage and test it. But does that sound like its a fuel pump problem?

[Pistol Pete]

The fuel pressure guage will tell us if it's a fuel problem for sure. (it probably is)

How old are your plug wires? Take a spray bottle of water out with you next time. When the boat starts sputtering, spray a mist of water on all the plug wires. (try not to get any in the intake while the motor is running) If the plug wires are breaking-down in the heat, the water will make it easier for them to short to ground.

[OLDGUY]

I replaced the plug wires last year. This problem started about a month ago. I go all year around. I was changing the plugs earlier this year and one of the spark plug boots was stuck to the spark plug. I pulled so hard trying to get it off that I jerked it off of the plug wire. I reattached it and no problems. That was several months ago and this problem just started about a month ago. Could I check the fuel pressure in the driveway on a fake a lake or should I put it in the water?

[Pistol Pete]

You certainly can check the fuel pressure in the driveway but, it's probably gonna be normal. We need to see what it is when the engine is acting up.

[OLDGUY]

Thanks Pete I will try that. By the way It took me 5 years to break 100 posts.

[Pistol Pete]

Yeah,

I hadn't seen you on here in a long time. I never forget your avatar. And, I remembered your a fellow foiler.

[OLDGUY]

My avatar was my wifes pet squirrel. It died they only live like 3 years or so. The picture was taken in our bedroom. I'm on here everyday I just don't post that often. You landed that gainer yet? The advice Billair junky gave you was right on the money. Cut hard away from the boat gain some speed, ride the foil up then dip it and throw your feet and head back. Be real aggressive throw it hard and try to throw it up so you get some air. Spot your landing, by that I mean look back when your flipping and when you come around you will see the water and this will help you land. Your a young man you can take a few crashes till you land it.

[Patrick]

I've got a 2003 Wakesetter VLX with the monsoon 335 indmar efi with the exact same problems. I've had 2 mechanics check it out and were not able to resolve anything. It temporarily worked then it would act up again. It's been going on since the end of last season. Basically If I fill my tank to full it will run fine until just about 1/2 a tank then the symptoms start. The closer to empty the worse it gets. Power cycling the boat helps for a few minutes then it acts up again. The lower the amount of gas in the tank the slower the speed to maintain the boat moving. I've had the fuel filter changed by my mechanic and he also hooked it up to a different gas tank and ran the boat through my fuel pump attached to a different tank and had no problems. I've spent about $1000 in 2 different mechanics trying to fix it and no luck. I'm sure this is happening to more than just 2 of us, so there has to be some fix. If the pressure is off on the fuel lines what would be the fix?

[footnlongline]

I've got a 2003 Wakesetter VLX with the monsoon 335 indmar efi with the exact same problems. I've had 2 mechanics check it out and were not able to resolve anything. It temporarily worked then it would act up again. It's been going on since the end of last season. Basically If I fill my tank to full it will run fine until just about 1/2 a tank then the symptoms start. The closer to empty the worse it gets. Power cycling the boat helps for a few minutes then it acts up again. The lower the amount of gas in the tank the slower the speed to maintain the boat moving. I've had the fuel filter changed by my mechanic and he also hooked it up to a different gas tank and ran the boat through my fuel pump attached to a different tank and had no problems. I've spent about $1000 in 2 different mechanics trying to fix it and no luck. I'm sure this is happening to more than just 2 of us, so there has to be some fix. If the pressure is off on the fuel lines what would be the fix?

This maybe a stupid question but have you checked to see if you vent hose is not kinked or obstructed. Since both of you are experiencing problems when the tank draws down I would look here.

[Patrick]

This maybe a stupid question but have you checked to see if you vent hose is not kinked or obstructed. Since both of you are experiencing problems when the tank draws down I would look here.

I have not checked that but will look this weekend, I would think if that was the case that it would act up like that with a full tank, half tank, or near empty though...

[footnlongline]

I have not checked that but will look this weekend, I would think if that was the case that it would act up like that with a full tank, half tank, or near empty though...

Nah, when it draws down and the vent is ubstructed it creates a vacuum in the tank. If you gas cap hisses when you take it off after skiing a bit, you can be sure your vent line is pinched

[OLDGUY]

This maybe a stupid question but have you checked to see if you vent hose is not kinked or obstructed. Since both of you are experiencing problems when the tank draws down I would look here.

I made sure to mention I had gas in the tank because one of the comedians on this board would have said "Are you sure you have gas in the tank?". I don't have a kink in the vent hose that was one of the first things I checked. I talked to several mechanics I know and they all seem to think the fuel pump was going out. It's 9 years old with a 1000 hours on it.

[Pistol Pete]

I talked to several mechanics I know and they all seem to think the fuel pump was going out.

Ever get that fuel pressure gauge on it to confirm?

[OLDGUY]

Bought one yesterday will hook it up this weekend. Problem if it is the pump I won't get to ride this weekend if I don't order one. What do you think I should do? To get it by this weekend I need to order it tommorow.

[Pistol Pete]

$1 in proper diagnosis is worth more than $100 in guessing and throwing parts in.

[conbon_88]

I was having similar problems. It was almost like a vapor lock and generally happen after taking a break then going back to towing, as soon as you get up to speed it sputters out. The engine will start again after about 40 minutes. I changed the plugs, filters, roter etc too with now resolve. I saw many posts on here about others having the similar problem (this was 2 years ago) and it came back to the increase in the ethenol in the fuel makes the fuel pump heat up in the boats with the EFI. There were many solutions and I took 3 that have seemed to help: I add Marine Stabil everytime I fuel up, place a cool wet towel on the fuel pump, and when taking a break prop the engine cover up so air circulates (but no all the way open).

When it is hot and I am pulling skiiers I run with the towel on my fuel pump and continue to dip in in the water to keep it cool. It cools the fuel pump and I have not been delayed any further by this problem. One guy rigged up a actual ice pack. I had several folks look at my boat too, and the only solutions that worked I found here on MalibuCrew.

[Aquadisiac]

I'm not sure if your problem is the same but I had a plugged fuel pump vent tube (small flexible tube coming off the fuel pump was gummed up inside). Symptoms were the same as you described. The pump would work fine for a while and the give random fits. When the vent tube plugs it doesn't allow the fuel pump diaphram to operate. I went 1 1/2 seasons on the lake before I got lucky enough to figure it out. Since the problem was random it always checked out with good fuel pressure in the driveway. Good Luck

[conbon_88]

I'm not sure if your problem is the same but I had a plugged fuel pump vent tube (small flexible tube coming off the fuel pump was gummed up inside). Symptoms were the same as you described. The pump would work fine for a while and the give random fits. When the vent tube plugs it doesn't allow the fuel pump diaphram to operate. I went 1 1/2 seasons on the lake before I got lucky enough to figure it out. Since the problem was random it always checked out with good fuel pressure in the driveway. Good Luck

Lately I have had problems when cold starting the boat, it turns over but doesn't fire. Once I get it started by spraying some fuel in the carb. it will stay started and restart all day, the problem is just on the cold start. I started with the battery and it checks out all good. I have changed the fuel filter. Do you think the fuel pump vent tube could be the cause of this problem?

[Aquadisiac]

Lately I have had problems when cold starting the boat, it turns over but doesn't fire. Once I get it started by spraying some fuel in the carb. it will stay started and restart all day, the problem is just on the cold start. I started with the battery and it checks out all good. I have changed the fuel filter. Do you think the fuel pump vent tube could be the cause of this problem?

This sounds more like a choke problem to me... you may want to use some spray carb cleaner on all moving linkages and then check the choke for proper operation. Also check to see if the priming pump is squirting gas in the carb when you move the throttle. Could be getting dried up and not priming after sitting for a while. My problem always happened after running for a bit.

[buBarry]

i know you said you checked the intake screen as described in other posts, and not to be a "is there gas in it?" guy, but did you remove the barbed fitting attached to the fuel pump.

My symptoms were contstant, indpependent of hot or cold but otherwise identical to yours. Ran better with more gas. I kept thinking it was water in the gas because it got better when I would add gas and the treatment additive.

So I performed the fuel pump intake screen cleaning descibed in the other post. The only thing was I didn't remember anything about taking the barbed fitting off of the fuel pump. So I was pretty dissappointed when I pulled the hose off and there was no screen on it. But then I unscrewed the barbed fitting, checked it with a mirror and lo and behold a screen.

Cleaned it as described, runs like new now.

[OLDGUY]

Do any of you think a bad sending unit could cause these types of problems? The trouble shooting part of the Indmar manual says oil pressure ,water temp. or high transmission temp. could cause the ecm to put the engine in to limp mode. These engines have two sending units one for the gauges one for the ecm. So even if the gauges were reading right the sending units for the ecm could be bad. What do you think? Right now the boat is just about worthless if you can't ride behind it.

[sgt1970-442]

Do any of you think a bad sending unit could cause these types of problems? The trouble shooting part of the Indmar manual says oil pressure ,water temp. or high transmission temp. could cause the ecm to put the engine in to limp mode. These engines have two sending units one for the gauges one for the ecm. So even if the gauges were reading right the sending units for the ecm could be bad. What do you think? Right now the boat is just about worthless if you can't ride behind it.

yes on the sending unit being bad. have you got the fuel pressure gauge put on the fuel rail?

you'll need to get the boat out and when the problem starts check that gauge as pete said. if it still reads good pressure

then i would get into the electronics and check ohms and resistance on sensors and the ecm.

as pete mentioned parts changers are not real mechanics.....