Sea Doo x-20 w 2002 Mercury 240 EFI M2 Jet Drive Engine Problems

[Big Tom]

I have a Sea Doo x-20 w 2002 Mercury 240 EFI M2 Jet Drive and have posted before. Dr Honda provided invaluable technical assistance and we solved our problem.
We now have a new problem. The engine will run fine for an hour or two, and then seems to bog down and smoke due to excessive oil in the gas. Draining the fuel from the low pressure fuel pump (about 2 cups of gas and oil mixture) show oil in the mix. After draining the engine will run fine w/o smoking or missing and achieves top rpm. But then after running for an hour or two the same thing happens, smokes misses and runs poorly.

We think we are getting too much oil mixing w the gas like the oil pump is pushing too much oil into the fuel. Thanks for any assistance.

Big Tom

 

[Waterluvr]

Morning Tom, I'm seeing similar symptoms on aging 240's that pass compression and ignition checks and replacing the TPS has resolved the problem. To be thorough when one of those comes in they are pretty easy to check out just by measuring resistance values on the temp senders first after checking both port and starboard banks for compression and ignition.

Use of a proper CDI ignition tester on the wire sets such as sold by Stevens instrument isn't an option on these, I use a Stevens marine instrument S-48H on those powerheads to measure the wire pulse. Ignition problems will also cause your symptoms when things get warmed up.

If you need help checking the TPS I'd refer you first to the service manual as it's not optional to diagnose an EFI without one and I'll gladly answer any specific questions you might have otherwise.

 

[Big Tom]

The TPS was just replaced and appears to be working fine.
To further clarify, the issue appears to be a slow increase in oil to fuel
mixture the longer the engine runs to the extent that it will ultimately get
so rich with oil that it fouls out the plugs. I can drain the high pressure
fuel pump and see that the oil/fuel appear almost black due to the high
concentration of oil. I can then turn the key, let the high pressure fuel
pump refill and then drain it again. The engine will then start up and run
perfect for a few hours. Then the smoking returns as the oil to fuel mixture
rises again. I'm wondering if the oil could be bleeding past the oil pump?
Something is causing the oil ratio to increase.
Thanks very much for responding to my post, hope can help. The TSP was pretty expensive to replace ($480), but it fixed an earlier problem. Its been running fine for about 11 mos. I do have the the test harness to test the TPS if you still think that may have gone south in 11 mos with only limited weekend use.

 

[Waterluvr]

Ouch, those TPS are really painful to replace. So I really need to know what the results of the last DDT scan were to point you in the right direction here, anything less on that motor is just an exercise in guessing and or hackery and I don't go in for that it sounds like you've had more issues than usual with it at this stage. Some of that can be done with a multimeter but at this point I think your past that stage.

Has a tech had that hooked up and do you have any results on a work order you can share with me? Something as simple as the darn air intake temp sensor can cause that to happen, any codes should be on a work order if it was scanned and I would really like to know the input and output values on the current TPS now that your having this problem.