Question for Bill~ What if?

[drewmark19]

I have a 95 XP with a 720cc engine and have rebuilt both carbs which included replacing the needles and seats (per your recommendation). I do not have a pop-off pressure guage, so I took the carbs to a shop to be tested. The shop set everything up and said I should be good to go. Not So!

My original problem was and still is that the carb/s allow fuel to flow into the case even after the engine is shut off. To double check, I took the carbs off of my sister's 95 XP which runs fine. Even with the good carbs installed, the same thing happens.

I have not checked the return line to ensure that it is not clogged. If the return line is clogged, could it cause the gas that should be going back to the fuel tank to trickle back into the case and cause the engine to flood???

If it's not a glogged return line, what would you suggest?

[Bill O'Neal2]

Re: Question for Bill~ What if?

If your sister's "good" carbs leaked fuel into your motor too, are you sure you have fuel leaking in, or is it your imagination, and you have another problem alltogether?

The only possible way a carb can leak fuel into a motor is through the needle and seats, not though a return line.
If your needles and seats do not leak, then fuel is not leaking into your motor.

[drewmark19]

Re: Question for Bill~ What if?

After I installed the carbs and before installing the flame arrestor etc.. I started the engine and then shut it off while looking through the front carb. After a second, I can see fuel dribbling down the side of the carb. The ski starts so so if I turn the fuel selector knob to off and hold the throttle wide open while cranking.

[Bill O'Neal2]

Re: Question for Bill~ What if?

Then the diaphram is holding the needle lever open so fuel can leak past it and into the motor.

You need to do the pressure test on the carb after it is fully assembled. It must hold 15 psi minimum without leaking. This is a precribed test other than just checking the pop off pressures and most mechanics simply do not do it.

[drewmark19]

Re: Question for Bill~ What if?

When I swapped the carbs from my sisters ski, I did replace the diaphrams that were in her carbs with the new ones that I had in my carbs. For the lack of better wording, would the tits on the new diaphrams be longer than the ones that were on the old ones? I purchased the rebuild kits for my ski from SBT, and I just placed another order this morning so I can rebuild her carbs too. Can I ground down the tits or should the lever be readjusted?

[Technical Support]

Re: Question for Bill~ What if?

The lever must be level with the carb body. If it is, yes you can grind the nub down.