Turns over just won’t start

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meaubry

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I have a 2000 Challenger 2000 with a 240hp Mercruiser M2 efi engine. I’ve had it since it was new (only owner). I had troubles a few years back that I was able to figure out and replaced a sensor. No trouble since then until this past Sunday. Started fine and took off like normal, went about 1/2 mile and just shut itself off. Tried restarting and it wouldn’t restart. Waited 5 minutes, and it restarted. Idled back to the launch. Replaced the battery (7 years old) Replaced the plugs, Used my computer with Diacon Rinda efi diagonostic software and it showed all sensors tested good. I used a multimeter to check resistance of stator and trigger - both tested correct for ohms value per service manual. Replaced the ignition control module with a good spare that I had from last problem years ago. Pulled new plug out of two spots and they have a brown residue with a small amount of fuel/oil on them.
I haven’t checked the cdms or injectors them selves due to the difficulty to get to them.
Adjusted the TCM to 0.3v and checked it went up and down in value as I rotated it.
Worried that it might be the ECM. PN is 824003T31 supersedes 824003A0
Have had no luck finding a new or even used one. Anyone got a line on one? Or a clue as to why it turns over but won’t start.
Baffled and frustrated with this situation.
 
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Update - for Snits and giggles, I manually rotated the throttle adjust a few times. Then, I had the wife turn the key while I held the throttle adjust lever on the throttle cable just a tiny bit. The engine started right up and I was able to throttle it using the spring loaded adjust lever.
So, after I repair the leaky vapor separator which I opened to check the final filter. I will reinstall it and try to determine why and how to adjust the spring loaded throttle cable to the position that makes it start.
Let’s hope this works.
 
So, reinstalled the vapor separator and found the following regarding the throttle cable adjustment. After loosening the screw, I moved it along the slot until it was all the way to the end of the adjustment slot. Tried starting it, and at idle it seemed to be to high rpm. Readjusted again, to halve the distance from the last time and tried again. Almost started. The cam shaped lever seems to have a dimple worn right at the idle position. By moving the lever until it doesn’t sit in the divot, it starts.
Why would the throttle cable adjustment of that small amount be enough to allow the engine to start?
 
Something doesn't make sense, after shutting off while cruising the boat, once restarted, would only idle back to the launch?

How about checking fuel rail pressure?

One of the big tuner outfits can get you an ECM of whatever flavor you want, I'm sure.

This might be the outfit I was referring to:

OPTIMAX 300XS ECU Flashing & Kits
 
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Something doesn't make sense, after shutting off while cruising the boat, once restarted, would only idle back to the launch?

How about checking fuel rail pressure?

One of the big tuner outfits can get you an ECM of whatever flavor you want, I'm sure.

This might be the outfit I was referring to:

OPTIMAX 300XS ECU Flashing & Kits

Thanks - for the link I will follow up.

After restarting on the lake, I choose to idle back - it might have accelerated, but we were close enough to shore to not have to.

Checked pressure and it read 34psi at shrader valve
 
That was one of my concerns also. Planning on pumping out what’s left in the tank, which is half full, and refilling with 5 gallons of new gas. Going to also pull the filter that looks like a oil filter and replace it if I can locate a new one. Finding some parts for this engine is getting to be kinda difficult.
The suddenness of the way if just shut itself off originally, seemed like it was more electrical than fuel too me. No sputtering or running rough - it just shut off like that.
Checked, double checked, and triple checked the lanyard kill switch, but it seems to be okay.
Upon further review, the head temp sensor ground wire has a small crack in the insulation, near where it enters the sensor. Maybe, it was shorting out?
Replaced it and after doing the fuel swap mentioned earlier, I hope to get it back in the lake and giving it a trial run. If the weather cooperates.
Anyways, Thanks for the suggestion.
 
Remember, this powerhead came from an outboard and there's a lot of support for those still. Mercury has been very good about providing support for sportjet through the years (I've been surprised, but I seem to live in my own world outside this particular forum), not sure the current status but you may be correct.
 
Boat started in the lake and went for a ride. Accelerated and took off as normal, got about a half mile away and going 35mph it shut off again. Started and went a few hundred yards and it shut off again. Started up again, and idled back to the dock. I checked the muffler exhaust tube because its a little soft. But not delaminating as far as I can tell.
I think the computer is being told to shut the engine down. Wondering if sonething in the jet drive is the problem. Could a bad bushing or sonething associated with the impeller or jet drive not allow enough water to flow thru the engine and cause the head sensor or coolant temp sensor to signal the ECM to shut off the engine??
Time to look at how the water flows to cool things off.
 
On your throttle cam- there is a molded line that should line up to roller on throttle shaft. There is a small "low spot" there also. If you have a big depression there, replace the cam. Don't forget the plastic bushings the cam moves on.

Have you checked the kill switch cap? When the rubber gets old, it does not hold the plunger down and it will kill the engine. Do you have any spark testers you could check while engine is running/dies.

Check for water in the gas by removing canister filter and dumping it into a container. Also, open the drain on side of the VST and drain into a container.

Fuel pressure- monitor while running. Does the pressure stay up when the engine dies or does the pressure fall and the engine dies? If second scenario, repeat with voltmeter on pump wires.

At the pump- there are no sensors on the pump. However, there was someone here who had the pump shaft seize to the bushings in the stator. The bushings are plastic. The oil had leaked out of his stator and he melted the bushings to the point he had a very hard time removing the stator.

Are you getting water out of the pee hole?
 
Okay - there’s a small indent and I see the alignment lines on the wheel and the cam lever. I suppose after 19 years the wheel and cam lever may have worn. Will try to find and purchase replacement parts.
Checked the lanyard kill switch. It was okay.
Need to check for water in the gas.
Need to capture fuel pressure and cdm voltage while running as suggested
Need to find flywheel removal tool in order to physically check stator and trigger as suggested. Found one online for $158 - hoping to find that item for less.
Not sure what the pee hole is?
 
Pee hole is on the stern, warm water should be coming out when engine is running in the water.

Trigger is checked at the connector, top of engine aft of flywheel.

Puller should be about $40. Make sure it is specific to Merc.
 
Found the brass fitting and will blow air through to verify it is not blocked.

Already checked the resistance of both the stator and trigger. Both checked okay.

Flywheel Puller ordered from Mercruiser online Parts store $146. Part # 849154T1
 
I checked my trigger and it was perfect to specs.
Replaced it anyway. Now revs from 1200 to 6200 smoothly.
 
Waiting for flywheel puller to arrive to further check stator and trigger.
Wondering why the darn throttle is so sensitive to adjustment for starting.
Just a slight lift of the lever will make it start or not start. Not sure if the trouble starting has anything to do with it shutting off when running at a higher speed.
 
Seems that is what is happening. I adjust the throttle cable attachment and got it set now.

And while working on it today, found a pinky finger size hole in one of the top of one of the rubber exhaust tubes that goes into the muffler.

Anyone know where to buy that size rubber tube?
 
Marine supplier. Maybe West Marine?

Many of the exhaust hoses have steel wire in them. I don't think our SeaDoo hoses have the wire.
I am not sure how you can get around the molded bend in the hoses.
 
Yes, called West Marine and will be picking up hose tomorrow morning. They do have wire in them. I am hoping to be able to use my heat gun to kinda form the slight bend. We will see.
 
What a struggle it was to get the hose to fit. Anyways, got it on and re examined the electrical diagram to verify how the temp sensors were linked to various items such as the ignition control module and the electronic control module.
Changed out the coolant temp sensor on the starboard side of the engine.
Started the engine on a hose with success.
Took it to the boat launch and went for a trial ride. Boat started and drove around okay at various speeds without dieing.
Felt it was idling too high, so I readjusted throttle cable.
Boat wouldn’t restart - so, I fooled around with the forward/reverse lever trying to get it to settle in a good feeling neutral position.
Boat started nicely. Restarted every time. Just barely moved the lever, and it turned over but wouldn’t start.
Guess I better take the cover off and check to see if the switch down below needs to be replaced.
Doesn’t explain the reason the engine died, but perhaps the temp sensor does. Now, I’m thinking that the neutral switch has to do with starting problems.
 
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Final update - took the boat in to a mechanic that could check compression and found out that I only have like 100 on 4 of 6 cylinders.
When I took it for a test run last, the boat started right up and idled okay. Took off okay, but seemed a little more hestitant than ever before. Didn’t die during the test ride after changing the temp sensor. Thought I had it fixed, but couldn’t figure out why it just seem to run 100% - like before it just stopped while driving along a couple weekends back.
With the diagnosis and need for a engine overhaul, I’m done with it.
Time to move on.
Best wishes for all you Seadoo sportboaters.
Enjoy them while they last.
 
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