1998 seadoo xp ltd 951 spark problem - weak intermittent spark

[pustanio]

HI guys
I have had this XP for 3 seasons, the first season it shit itself after 20 hours, we rebuilt it last season and didnt use it, this year it starts and runs, but runs like crap.
It pops and misfires at any rev.
Once it gets hot (5-15 minutes) it drops spark in one cylinder and I have to idle back to the ramp.
I have checked the spark, so its not fuel, it really does drop spark on one cylinder.
The odd thing is, its the spark plug, not the lead/cylinder. When I swap the plugs over between the cylinders, the problem swaps cylinder with the plug (ie the plug that fails on cylinder one, fails on cylinder 2 when we swap them over)
I let it cool down, put another set of brand new plugs in it, and you can see that one has weaker spark (its just off blue towards orange) but still a full spark and doesnt miss a spark when cold.
I have checked my earths at the coil with a multi meter and get 0 resistance back to the engine.
Think I have to take it to the shop but thought I would try here first to see if anyine had any ideas.
thanks

 

[pustanio]

forgot to add even with the small misfire, while it does have spark on both cylinder I can still ride it properly, havent had it wide open yet but it will pop out of the water, rev correctly and pull, it just sounds like shit with a constant misfire out the back, then it stops.

 

[Seadoobuddy]

I really can't tell you why the problem swaps between cylinders like that.
But as far as low/no spark, have you tried cutting off 1/4 inch of the plug wires and then reattaching the boot. The machine is 14 years old and may have lost some sparking power at the leads to the plug.

hopefully some of the experts here will chime in after the games today.

 

[pustanio]

thanks for the fast reply, I did search the forum yesterday and found that info, did that last night - havent water tested it yet, but can still see a difference in spark colour when its cold.
worth noting that the spark plug that failed works again when its cooled down.
possibly could be faulty plugs just odd that I could get 2 different plugs doing the same thing right?

 

[Dr Honda]

Sounds like you may have a bad coil... or the ground to your rear electrical box is bad. BUT... cutting the wires back a little does help a lot of times.

 

[pustanio]

when you say elecrical box, do you mean the box that houses the coil? If so, checked that one and it earths back to the engine with no resistance.
Thanks

 

[Minnetonka4me]

Might be a stator too...those 951s always knock those pieces out of the bendix and they get in there and chew everything up.

 

[pustanio]

Might be a stator too...those 951s always knock those pieces out of the bendix and they get in there and chew everything up.

Is there an easy way to test the stator with a multi meter, or do you suggest pulling it out and looking for visual faults?

they dont like look easy things to work on, I am used to working on bikes where you can get at things
How do I get at the stator?

 

[Minnetonka4me]

Well lucky for you it isnt that tough on that XPL. Take the front motor mount out and toss a block under the motor. Then take the 10mm bolts out and off it comes.

Since yours is intermittent I would just pull it. Good to see that all is good in there, and you can put a little RTV on it when you reinstall it.

 

[92rslt1]

I doubt its the stator. All the stator does in these is charge the battery.. more likely the pick up coil. Mine ran fine with a totally fried stator.

 

[Minnetonka4me]

They get damaged causing an open on a wire...but yes its likely the pickup which is under the same mag housing. They either break or get a bunch of fragments on them causing them to short.

 

[99spxxx]

Cheap start is just cut back the spark plug wires a 1/2 inch...