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98 xpl spark plugs fouling

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Its a98 xp limited 951. I had the motor rebuilt completely by seadooengine shop and the compression is right on dot, i check it frequently. I have been ngk plugs (BR8ES), doing research i have found the gap should be .022-.024 but all the plugs i buy are gapped closer to .028-.030. Will this make a huge difference? Thanks
 
my Grandpa has been fixing motors for 60 years, and old guys seem to always know right, andf he SWARES by a correectly gapped spark plug. he will physically not allow me to run a plug if it is "close" because he belives it needs to be right on measurement. so moral of the story is, if the gap should be .022 - .024 than make it that gap. because the manufacturer would have put it at .028 - .030 if it was good for the motor. but they didnt. but whether or not this is your only problem, now thats another question.
doc probally knows though ;)
 
Sorry... I guess you said 98 XPL in the title.


The plug gap will help... but it still wouldn't be fouling every trip since they are the proper heat range. You would be more likely to have a noticeable miss-fire.

Crisso has a good point. Are you running the injection, and extra oil in the main tank?

You say the compression is good... but you didn't give us a number. What is it?

When the engine was rebuilt... were the reeds replaced? They have a tendency of cracking, and causing running issues.

What kind of oil are you burning?

Any engine mods?
 
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the oil pump is the only source of oil and the engine now has close to 10 hours

120psi in both cyclinders

reeds are new

fully synthetic spectro

ALl stock no mods

Thank you for the replys
 
120 psi, gettin low on compression ???? who did it ???? im sure they will stand by there warranty ???? will they ????
 
You've got low compression, a fresh rebuild on a 951 should be 135. How many hours on the rebuild? I would contact whoever rebuilt your engine.

Lou
 
Im trying to figure out what i should do someone plz help me

I had to motor rebuilt by seadooengineshop, they said they completely changed everything out and that the head that i sent them was an SBT head that was chopped down. He said that the head is only capable of reaching 120psi. Also said that if i went through SBT it would be the same circumstance.

He also said because of warranty i could sent him the motor back, he would try to find an original head and he could get the psi up to 130psi but this could take time.

I am an amature and could really use some good advice on what to do please help?
 
I'm not sure what you want to hear and I'm not a professional mechanic, but I feel that the low compression is the reason why your plugs are fouling. I don't know exactly what a chopped head is but if its the same as a shaved head it would actually increase compression which can be compensated by using a thicker head gasket. Maybe the head gasket is too thick, IDK.

You could also take Dr Honda's advice, which is usually better than my advice and check the reed valves. Other than running a hotter plug which I really wouldn't recommend I don't know what to tell you.

Lou
 
Like said above I'm not a professional mechanic either. And I maybe wron but 120 sure seems too low, especially coming from the SeaDoo mechanic? I mean I'm not crazy am I? It just doesn't seem to add up that they would tell you that it can only reach 120psi. But yea, this does seem like a jonpb for Dr. Honda give it some time and I'm sure he will help you out.
Good luck and keep us posted on what you find out
 
You know,I just re read this and if it is miss firing, I had that problem before. What my problem was that the spark plug boot, (or whatever the correct erm is for the thing that connects to the plug) but the connection from that boot to the wire wasn't god. It was a poor connection causing it to hit or miss every couple bounces. I took the boot off and shaved down the wire a hair. ( just enough to get new mire shown through on the end) and screwed the boot back on. This could be your problem. I would try this
 
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