97 GTX Backfiring out of the carbs and exhaust

[aerovette99]

The ski ran flawlessly last year. It sat over the winter in my garage and did have gas in it. I came back this year and took it out and it popped and had no power, then died on the lake.
I drained the tank and added new 93 octane gas. Starting was tough, but after dumping some gas in the carbs, it finally started and ran (hose hooked up), but coughed and sputtered for several minutes. Neighbors thought I was shooting a gun. Never got any better. It still runs awful.
Is this a carb rebuild, power Rave valve rebuild or something else?

Any input would be great

Thanks
Dave

 

[Coastiejoe]

FYI, running on the hose should be only about a minute or so. The hose does not cool the carbon seal. Someone with more 2-stroke knowledge than myself will chime in for you. Generally speaking, popping and back fires are normally a timing issue.


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[howie099]

To me I would clean the carbs and power valves if you didn't store it properly over the winter plus its good to do anyways. Next I would look at the RV. If the RV gear\RV is worn out it could jump time. I would go through the carbs and PV to see if there are any issues if you don't see anything you might need to remove the intake to check the RV. Also I would check compression just to make sure. Its always good to check that.

 

[LouDoo]

It sounds like a timing issue to me also.

Lou

 

[Coastiejoe]

You do need to look at all the easy and simple things. We just had one guy that could not get his ski started. Took about 40 posts to determine someone else used it and added diesel to his fuel tank...

My point is, don't dig to hard until you need to. That said, your description is a perfect example of a timing issue.


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[soccerdad]

Could be timing, but something has to break to make that suddendly jump. Could happen, but not as likely. I love joes answer. Start easy. Check all connections for corrosion. Just remove and reconnect everything and make sure all grounds are tight. Then try disconnecting the voltage regulator. A bad one could cause all kinds of havoc. Hopefully you will just find that some connection was bad.

But- I had bad backfiring on my GSX. My 96 has a 97 mpem in it that also has the CDI imbedded (just like your 97 does). The CDI went bad and caused LOUD cannon fire backfiring. It showed that it had good spark, but I think it was sporadic and when it did fire-look out! New MPEM and I was good to go. If your timing turns out to be good, and you have no where else to look, then contact [MENTION=41828]Minnetonka4me[/MENTION]. He has mpems and he is the only guy that I know will sell you one, and then take it back (for a nominal restock) if it does not fix your problem. Anyway, start simple and good luck!