Seadoo needs new spark plugs every hour??

[donaldjboyer]

Hi all,


Seadoo GSX 1997
110 hours


I have had an issue over the last few months where I'll install brand new spark plugs in this machine and it'll run fine for approx 1 hour and then start running rougher and rougher over a few minutes until it'll barely run. The only remedy is to install brand new spark plugs again (which only last for an hour). And in a recent run, the 'check engine' light came on the dash briefly also.


I have cleaned the carbs, fresh fuel, new battery (fully charged). When I have checked the voltage at the battery (while running on the garden hose) the voltage jumped around quite a lot, but the display refresh on the digital multimeter was slow which made it difficult to see what was going on.


I am thinking the voltage regulator might be at fault, but could you please help me by suggesting what I should look at diagnosing? (trim spark plug lead ends? check negative cable from battery to engine etc).


Thanks in advance,


Donald.

[TimeBandit]

Are you saying after that hour of run time, the plugs are dry and "look" normal - yet are dead?
Spark plugs can fowl-up if the air/fuel and or fuel/oil are not within specification - aka a really rich oily condition. The carbon soot build-up on the electrode surface can become insulative enough for the spark not to jump. Even worse, actual build-up to the point the gap is bridged. You should post pics of the "bad" plugs.

That said, curious ... have you tried to resurrect the bad plugs? Aka, with the sets of plug you have already went thru and suspect are "bad", can you clean (wire-brush in insolvent) then up enough that they work again for a while?

Back to my 1st question.... if soot/carbon/oil is not the issue... take a "bad" plug to an automotive parts store or car shop to test the plug electrically on a tester.
Once we have a clearer understanding of what is wrong with the plugs, we can better focus-in on want might be wrong with the carbs, oil injection, or electrical components.

[Pacer]

A guy brought me an STX DI several years ago and said the same thing. Plugs only lasted 30 min to an hour. Turned out his emm was overheating because of a plugged cooling line and it cooled off enough to run right in the 10 minutes it took him to change the plugs.

[Myself]

This happens on older Seadoos. Your inner crank seals have gone bad. They are letting so much oil seep into the cylinders that it's fouling the plugs. I'm guessing they are very wet oily looking when pulled. Don't freak out! You can milk it along for a while without rebuilding it. Siphon or empty out the 2 stroke oil. Remove and cap off the 1/4 inch line from tank to oil pump. Put some stp oil stop leak into the oil tank along with about about a quart of 75/90 synthetic gear lube. Now premix your gas at 40:1. Done! The stop leak will help swell the shrunken inner crank seals and the gear lube will keep the rv lubed while being thick enough not to seep through.

[donaldjboyer]

I should have included a pic of the plugs:

[TimeBandit]

Piston slap??

[Myself]

Piston slap??

Uhhh, ya......is it just the angle or are those gaps smashed closed??