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Just wanting to get some ideas on where to go next. I've got a 1998 Formula III 600 triple. I've got one cylinder that is filling up with gas. I took all the exhaust pipes off and started up the engine. After it was running it was spraying gas out of that cylinder every revolution. Here is what I've done to try and fix it.

I checked spark, it looks really good.
I replaced the main needle and seat on all 3 carbs.
I reset the float level on all 3 carbs.
I reset the choke on all carbs.
I checked the fuel pump.
I replaced the fuel filter
I've ran a compression check and got 115lbs on all 3 cylinders.
Visually the problem cylinder looks scored up when I look through the exhaust port. Could this be a ring problem? If so, why would there be compression? Any idea what it could be?
 

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My first guess would be that you are getting full compression when you pull it over because it turns relatively slow with no load, but then when it is running fast with a load it then starts losing compression from that scoring. Not really sure about that, 100% guess.

There are other things to try first...If the main jet in that carb was loose or had fallen out (or just the wrong main jet in there) this could happen. If your carbs are not fixed onto an assembly you could try swapping the order for a test run to see if the problem continues on the same cyl or follows the carb switch. If the spark plugs all fire at once (most 2 strokes do but check first) I would advise also try swapping the plug wire order to make sure the problem isn't just a bad/inconsistent wire. Obviously you want to eliminate any other possibilities before you go and rebuild your engine, at least I would.
 

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Discussion Starter #3
My first guess would be that you are getting full compression when you pull it over because it turns relatively slow with no load, but then when it is running fast with a load it then starts losing compression from that scoring. Not really sure about that, 100% guess.

There are other things to try first...If the main jet in that carb was loose or had fallen out (or just the wrong main jet in there) this could happen. If your carbs are not fixed onto an assembly you could try swapping the order for a test run to see if the problem continues on the same cyl or follows the carb switch. If the spark plugs all fire at once (most 2 strokes do but check first) I would advise also try swapping the plug wire order to make sure the problem isn't just a bad/inconsistent wire. Obviously you want to eliminate any other possibilities before you go and rebuild your engine, at least I would.[/b]
 

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Thanks for the tip, I tried switching the carbs around. The problem is definitely on that cylinder because it did not follow the carb.

I also took apart the RAVE valve and cleaned it up good. Then I took apart the reed valve and visually inspected it. Cleaned it off, blew it off and reassembled. Still no luck, the problem persist. Any other suggestions? I really don't want to start working on the motor if that isn't even the problem.

Thanks
 

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Which cylinder is it ?. If the cylinder that's spewing raw gas is the same one that the fuel pump pulse line is connected to, remove the pulse hose and block the crankcase nipple. Running good now? Your fuel pump diaphram has a hole in it.
 
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