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2006 Sea Doo Speedster wont stay running

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Re and Cheryl

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Trying to help out a friend with his Speedster. I'm a life long mechanic but boats are new to me. Engine in it is a fuel injected 2-stroke V6. according to him it was running fine last summer when he stored it. Over the winter we replaced the plugs and the fuel filter, after which we started it and ran it for 20-30 seconds. it ran fine.

about a month ago we took it out for a shake down run. once in the water it started right up and seemed to run fine. But after less than a minute it began breaking up and would barely run, eventually dying completely. I'm going over it today. My initial thought was that there was air in the fuel system, but I dropped the fuel filter and it was full. Not sure if that means anything though. The electric fuel pump on the side of the motor also seems to be working.

What am I missing? Any ideas what to check?
 
We need to start with... what engine is it? There are 5 different mercury engines used in the seadoos. 210 carb. 240 EFI (Gen1 and Gen2) 250 Opti, 200 Opti.
 
I don’t know much about these motors, but It appears to be a 240EFI. The model number on the motor is S240J30YS

Dr Honda said:
We need to start with... what engine is it? There are 5 different mercury engines used in the seadoos. 210 carb. 240 EFI (Gen1 and Gen2) 250 Opti, 200 Opti.
Click to expand...
 
The serial number would be good too.

But.... The VST will separate out the air. So... since you think it's a fuel issue... check the pressure. There's a valve by the pump. It should be 36 psi.
 
Serial
Dr Honda said:
The serial number would be good too.

But.... The VST will separate out the air. So... since you think it's a fuel issue... check the pressure. There's a valve by the pump. It should be 36 psi.
Click to expand...

Serial number is OE397418

What side of the motor is the pump? There’s a low pressure fuel pump on the left side of the motor.
 
Yes... the VST is the aluminum box next to the low pressure pump. The high pressure pump is in the box. The valve to check the pressure is just out the edge of your picture. On top of the VST, right at the edge of the picture... you can see the regulator. The valve is next to that.

Check the pressure "Key On". Then start the engine, and see if the pressure stays up.
 
My thought is that the fuel system has too much air in it from changing the fuel filter. We filled the filter with fuel before installing it, is there anything else that needs to be done to bleed air from the system?
 
You don't have to bleed air from the system. That's what the VST does. (purges air. Vapor Separator Tank) There is an electric, and pulse lift pump. As air pumps up the line... it just pushes up to the VST.
 
Dr Honda said:
Yes... the VST is the aluminum box next to the low pressure pump. The high pressure pump is in the box. The valve to check the pressure is just out the edge of your picture. On top of the VST, right at the edge of the picture... you can see the regulator. The valve is next to that.

Check the pressure "Key On". Then start the engine, and see if the pressure stays up.
Click to expand...

Checked the pressure at the VST and got nothing on my fuel pressure gauge. Is the high pressure pump electric, or driven off the motor?
 
The high pressure pump is electric. You should have pressure turning on the key. If you don't have pressure... we may have found your problem.
 
Dr Honda said:
The high pressure pump is electric. You should have pressure turning on the key. If you don't have pressure... we may have found your problem.
Click to expand...

Currently attempting to test power going into the VST. Also found two issues that I’m not sure if they are part of my problem or not.
#1 Behind the VST is a T in a vacuum line that doesn’t appear to be connected to anything
#2 The VST has a vacuum diaphragm on top with no line connected to it. I can see a dry rotted and broken line behind it, but no idea where it goes.
31000128-F2EA-4DD2-8C65-0E710AB736F3.jpegC1D5DDCF-FD40-4343-8B08-4E7E189AD2BD.jpeg
 
OK....

1) That's part of the bleed system. It draws pooling oil out of the corners of the engine, and puts them where it can be burnt. With that open, you are sucking raw air into the engine. In turn, running a cyl lean. (not good) There should be a nipple hiding in there, on the block.

2) The regulator is OK being open, but the hose that was connected to that goes into the EFI plenum. This is allowing air into the EFI. This isn't necessarily going to cause a lean point... but it may idle a little high. We think this hose is just to take case of any potential fuel leaks if the regulator starts to fail .
 
Here's some pics to help see it. My new hoses are yellow.

After looking at your pics... I can see the oil pump arm... so if you look at my first pic... you can see where the oil pump should be, and that the hose close to it is connected at the face of the reed block. After going back to your pic... I think I can see the edge of the ripped off rubber hose.

I may want to buy some 1/8" id or 3/64" id tygon, and replace those hoses.
 

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Dr Honda said:
OK....

1) That's part of the bleed system. It draws pooling oil out of the corners of the engine, and puts them where it can be burnt. With that open, you are sucking raw air into the engine. In turn, running a cyl lean. (not good) There should be a nipple hiding in there, on the block.

2) The regulator is OK being open, but the hose that was connected to that goes into the EFI plenum. This is allowing air into the EFI. This isn't necessarily going to cause a lean point... but it may idle a little high. We think this hose is just to take case of any potential fuel leaks if the regulator starts to fail .
Click to expand...


Ok, removed the fuel line running from the fuel filter to the VST and verified that I have fuel entering the VST. With the key on I can hear the pump in the VST running as well, however with my pressure gauge connected to the test post there’s almost no pressure. Bad VST, or could there just be a lot of air in it from changing the fuel filter?
 
Update... took the VST apart. The float is fine, and the pump works, although I’m only running it with no load and have no idea how it acts under load when pumping fuel.

Also curious what the flow of the low pressure pump should be. When I test it it seems to be pumping fine, but not a lot of volume after passing through the oil mixer and the fuel filter.
 
I was going to tell you to make sure the screen on the pump is clean... but since you have it apart... I'm guessing you can see if it's clean.

The pressure should be 36 psi.

The pump could be fine, and pumping. But the regulator could be bad. We've seen 2 on this forum this season. The replacement regulator is $300. But one member replaced it with a basic automotive adjustable unit. After the install... his engine was running great. I think it was $40 or $50.
 
I’m thinking it’s not the pressure regulator because I depressed the valve on the test port while the pump was running and got almost nothing. Even if the regulator was bad and stuck in full bypass there should have been fuel coming out.
 
No vst pressure?
Try swapping the 2 wires on the vst pump. Polarity matters.

When you had the vst apart, did you check that the float valve needle is free to move? They corrode closed from ethanol.
 
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