2003 SeaDoo Utopia with Mercury 240 EFI Fuel Problems

[Bryan Davis]

I have a 2003 SeaDoo Utopia with the Mercury 240 EFI (M2 I think) and have been having some problems. After taking it out of storage this year, it fires right up, but when I took it out on the lake, anything past half throttle and the boat seemed to stall out and surge. It would get power then die, then get power, then die... the more throttle I gave it, the more it just fell on its face.

After a lot of troubleshooting and testing things, replacing all the filters, plugs, etc... I tried a separate tank of fresh gas, same problem. However, when I first started it up on the fresh tank, I could give it full throttle right away, which worked, but slowly started losing power. Hooked it back up to the internal tank and its the same thing, so I don't think it's a fuel issue, but more a fuel pump problem.

So I did some testing and thinking... when I turn the key to the on position in the boat, I can see that some fuel pump fills a fuel reservoir and gives full fuel to the engine until that's empty - which I'm guessing is called the vapor separator tank? After a while, the boat seems to catch up and use the extra fuel I get in the beginning and starts to lose power and I have to reduce throttle to keep it from dying or stalling out because of what seems like it's running out of fuel.

What part do you think isn't working? There's at least 2 fuel pumps or maybe the float in the reservoir tank isn't telling it that it needs more fuel or is it the high pressure pump? Or something I haven't considered?

Any input would be greatly appreciated!

 

[biffdotorg]

I could be wrong, but I am thinking these Mercs have two fuel pumps. A low pressure pump to get fuel to the motor and a high pressure fuel pump to supply the fuel rail since it's EFI. You may want to check both, or refer to the service manual for proper troubleshooting of the pumps.

 

[Bryan Davis]

I could be wrong, but I am thinking these Mercs have two fuel pumps. A low pressure pump to get fuel to the motor and a high pressure fuel pump to supply the fuel rail since it's EFI. You may want to check both, or refer to the service manual for proper troubleshooting of the pumps.

Correct, there are at least 2. One's called a lift pump that seems to activate when I turn the key to "on" but only for a short time. Then there's a normal fuel pump in the vapor separator tank. I don't have an easy way to test that one. I've got both coming and am going to replace both. Hopefully that's the problem.

 

[biffdotorg]

Correct, there are at least 2. One's called a lift pump that seems to activate when I turn the key to "on" but only for a short time. Then there's a normal fuel pump in the vapor separator tank. I don't have an easy way to test that one. I've got both coming and am going to replace both. Hopefully that's the problem.

ya, I saw your post in the merc forum over on the Seadoo site. Honestly there is the largest collection of Merc powered Seadoo guys over there. I got most of my help from that crew.

Sad to say, as time goes on, the best resources sell those boats and move on and they desert the forum. DrHonda, over there was gold. That guy rebuilt a 240efi Merc from the ground up. Literally fixed a hole in the crank case and machined it back to spec!

Good luck!

 

[Bryan Davis]

Wanted to follow-up to this post with the solution. I disassembled the entire Vapor Separator tank and cleaned it out. Turns out there was a bunch of gelatinous substance (looked green) clogging almost 80% of the intake screen on the fuel pump in the VST. There was also some of it in the channel from the main part of the VST that leads to where the fuel pump sucks it up. Not sure what it was, but once cleaned and reinstalled, things worked very well.

Something else I noticed, with the lift pump, you can actually plug the connector in both ways, but it will not work when the polarity is reversed. You need to make sure to match up the red/black wires when you plug it in. The plug from the lift pump looks the same in both sides, so be cautious!

Thanks for all the help and suggestions!

 

[pmorita]

THanks for the follow up. There is some good knowledge on the Sugar Sand portion of the site as we have lots of these motors out there.