97 XP, MPEM tests good, coil replaced

[OC seadoo]

MPEM tested good by the captain. Started the 97 seadoo XP he had. Previously I was having an issue with only one weak spark when first pressing the start button at best. I replaced the coil with part #278001254. Now I have a consistent strong spark. The problem still remaining is when the start button is pressed the ski is doing a rythmic start and stop. About four crank overs and a hard stop. Picks up again with four cranks then hard stop. Over and over. All without letting up on the start button. Spark is there though. With spark plugs out it cranks over continuously with no hesitation but spark goes away after first crank... Starter has been replaced too. I purchased an odyssey battery and will try that just in case my old battery isn't pushing enough juice. What's next? Thanks for any help.

OC

[nmpeter]

well that's some good news.

likely the battery will get you going.

have a good voltmeter?

get it ready and when you get the new battery in, watch the voltage while cranking.

the other possible is that the timing is off ( way off)

[woodsrider40]

I had one the starter was grounding out the spark due to short in starter.

[OC seadoo]

Frustrated. New battery installed and the engine cranked over continuously but only the first time I held the start button. Then went back to intermittent crank crank crank hard stop, crank crank crank hard stop. All without releasing the start button. Then sometimes the engine would crank over continuously. But mostly it's a very rhythmic crank crank crank stop. Now I'm having an issue with the starter. Hit the start button and starter just spins but doesn't engage the engine....

*Bad new starter?
*Fly wheel missing teeth?

I have an appointment this Saturday to bring in the 97 XP to a different shop in sacramento where they specialize in seadoo. Pete I wish you were closer sir.

OC

[nmpeter]

add a damaged RV gear to your list of possible suspects, doubtful the flywheel is missing teeth

I seldom trust a new part until proven in battle

did the battery voltage show a sudden dip when the engine stopped during cranking?

[OC seadoo]

I bought a good multi meter tester. I'm kinda lost on what to do...I'll give an update on what capital marine here in sacramento says the problem is. Appointment Saturday at 9:30. When the XP went down in August 2014 I knew I burned up the starter. So it's been replaced. Then realized it would then crank with the weird rhythmic turning over so it was diagnosed by a different shop ( tsunami jet ski ) as failed MPEM. Sent off the brain to the captain and my MPEM started his ski. So replaced the coil that is found next to the solenoid in the front dry box. Now I have spark. But rythmic turning over remained. Until the XP decided to have the starter just freely spin when the start button is pressed. This thing is fighting me!! I need to get it going. Short window for water this year.

[SURFnTURF]

Try a temporary ground from the battery to the engine(jumper leads work ok) and see any difference

[OC seadoo]

Got news today. Turns out something called a "cup"on the stator broke off and took out the fly wheel with it. Got a used stator and flywheel. XP is now running. The shop did a lot of diag basically redoing what I paid the previous shop to do. Very happy with capital marine sports and how professional Moises their tech is. Very detailed in his process of fixing this issue. Going to pick it up this Saturday and go out for a test run.

Any idea what I could sell it for? I need to get a bigger 3 seater. I just wanted to get it running again so I could upgrade to something more family friendly. At the same time it's a fun fast ride I might keep it for the brats.

[nmpeter]

you can always check the KBB/nada for some average price data, but after all you've been through with it why not run it a while?

the ignition trigger was bouncing around in the flywheel housing. Not an easy problem to diagnose if the wiring shows the proper resistance and if the spark comes steadily.

Likely every few revolutions the ignition got a trigger far advanced of normal, which can stop an engine cold.

In any case thumbs up to CMS for solving this very tricky problem.

techs can do a lot by just listening.

case in point:

Had a Yamaha 1200 show up last week with the mechanic/owner telling me the number 2 coil is out and he knows this "for sure" since there is "a very weak spark" and when he pulls the cap off the plug while the engine is running, nothing happens.

Well it was #2 all right, but not what he thought. I pulled the plug, spun the engine and confirmed spark (not blazing, but when is a Yamaha spark ever blazing?). Put the plug back in, spun the engine to hear it run and immediately stopped and went into the shop for a compression gauge. The engine didn't "sound right" when cranking.

Sure enough, no _compression_ on #2

[OC seadoo]

So I finally had time to go out for the first run on Sunday since getting it running again. Just about 11 months since the last time it was out. First ride was great. Fired right up and went around the entire lake and up all the fingers. Probably an hour ride. A little hesitation out of the hole but that was always there. But great acceleration and throttle response after initial hesitation. Downer was that the VTS is now not working but at least it was stuck right in the middle. Came back in and had lunch. I noticed on the way in I had to keep my thumb slightly on the throttle or it was dying. Second ride after lunch didn't go so well. It had to be started with throttle fully depressed and ran rough all the way out from the shore to the wake zone. Absolutely no acceleration. Full throttle and all it would do is bog down and limp. Let up on the throttle and it would die. After a bit of trouble shooting I turned off the fuel switch with throttle fully depressed and after about 5 seconds I would get 3/4 acceleration then switch back on fuel. Never would get past 3/4 full speed doing this. I didn't want to blow the engine just in case I was leaning it out so I called it a day and trailered it.

Sorry for the story but I wanted to be detailed. Wtf am I battling now? Old fuel? I have only run 91 octane but 3/4 of the tank was from last August. I topped off the tank before we went yesterday with about 2 gallons. Carb issues from sitting? I checked the plugs and they were slightly black and not wet.

Thank you for any help
OC