2000 Mercury 240hp V6 EFI looses spark when I put the boat in the water

[tremmert]

Hello,
New boat to me. Engine runs fine (well, rough... but it starts on first try and will continue running). When I back the boat into the water, I start it before I disconnect it from the trailer. The motor starts fine, but dies after about 2-3 seconds. Then I can not start it any more. It looks like I am not getting a spark. No water in the bilge area either.

Any thoughts? I waited 24hrs, then tried again at the storage unit, and the engine started just fine. Tested a 2nd time at the boat ramp, and same issue. It started, died, then I couldnt start it again.

This motor is on a 2000 Sea Doo Challenger Jet Boat. I posted in this forum because I have been told that this is an outboard motor inside of a jet drive boat. Hopefully the Outboard folks will be familiar with this engine...

 

[Faztbullet]

Can you hear the fuel pumps running?????

 

[tremmert]

Yes, pump is running. I actually connected a pressure gauge to it last night, and it is reading 31psi.

 

[Canufixit2]

Is the boat on an angle when on the trailer in the water?? i.e. try starting on dry land then tip the boat on the trailer and see if it stalls?

 

[tremmert]

Yes, the boat is an an angle. Not much, but it is more of an angle than when in the storage unit. Tomorrow, I will start it on dry land, then tip the boat and report the findings.

 

[flyingscott]

It's an EFI motor the angle shouldn't matter. You need to do a spark and compression test.

 

[tremmert]

Well, I just completed the compression test, and here are the results: 130, 0, 130, 120, 120, 110.

I think that might be my problem. Man that sucks. Do you know how difficult it is to rebuild this engine?

 

[Faztbullet]

That not a easy one as if it needs machine work it needs to go to someone that does hi performance repairs

 

[Canufixit2]

It's an EFI motor the angle shouldn't matter. You need to do a spark and compression test.

Very true - however I was thinking of water in tank. bent/broken tank pick up tube or wire shorting ..... Moot anyway - it was a cylinder issue as you suggested. But How that makes a diff on an angled start?

 

[flyingscott]

Very true - however I was thinking of water in tank. bent/broken tank pick up tube or wire shorting ..... Moot anyway - it was a cylinder issue as you suggested. But How that makes a diff on an angled start?

It was never the angled start it is the fact it was in the water. The jets are direct drive motors so the minute you start it the pump is turning. By the nature of the design when they start they are running under load. I would call Mercury direct and see if they could recommend anybody in your area.

 

[tremmert]

Thank you for the feedback. So far, I have been quoted $4,000 - $6,000 for the rebuild. That seems VERY high to me...

I went ahead and pulled the heads off to inspect the cylinder walls. They look fine, and I dont see any cracks in the sleeve. Do you know if It is possible to remove a single piston, hone it out, and install a new piston without removing the motor?

 

[flyingscott]

Those quotes are right inline with what it will cost to do it. Motor has to come out to get the piston out. You could pull it yourself and save some money.