650/X-2 X2 engine hydrolocked with FUEL!!

[Caski]

Hey all,

I went to start my X2 last night after it was sitting on the trailor all day, and it was hydrolocked. Took the plugs out and the whole engine was full to the brim with FUEL. It's not the first time this has happened. The tank had been exposed to the sun for the day but the fuel cap was slighly loose. How come the fuel can enter the motor like that?

I've had the carby rebuilt twice with all new parts. I've never checked the pop-off accurately but with a bike pump it seemed ok.

I also have an issue where the engine will require 2 minutes of cranking before it will start, presumably the engine flooded with fuel while sitting. When it finally starts it runs rough and smokey as.

Any suggestions how I might rectify the problem?

Cheers!

 

[chriselmore_1]

sounds like a leaking needle/seat valve

 

[easyrhino]

primer pump?
diaphraqm leaking thru pulse line?

 

[Mr Bojangles]

Check the pop off, mine would do this all the time after a rebuild. I would do the pop off and the needle would just stay open flooding the motor

 

[FlightPlanDan]

had a similar issue. Some hold the throttle wide open while killing the engine to "fog" after rinsing. I never did this. I tried it. I was gas-dro-locked the next time I went to fire it up. (also, my primer lines were reversed)
I wish I could say for sure what actually caused it. But it was not needle/seat or pop-off.

 

[BruceSki]

I had this happen with a long exhaust hose leaning against the air holes on the diaphragm side of the carbs. turn the ski off and it would keep the needle held open and load up the motor with fuel.

 

[McDog]

Had this issue spontaneously happen on a gp1200 and again after a carb rebuild. I finally got fed up with it and bought some carbs off greenhulk and switched them out. Good luck.

 

[Caski]

Hey all.

Thanks for the very helpful advice! The problem has been solved and a couple of you were spot on, the needle seat valve was staying open!

I eliminated the pulse line by using clear hose and saw nothing passing throught it. I then removed the air filter/flame trap and watched as the carby mouth slowly filled with fuel when the tank was under slight pressure.

I went with 'Jayski' to borrow a pop-off tester and followed the procedure of removing the diaphram cover and diaphram an checking the pop-off. It popped at around 16psi (if i remember correctly) then sealed again at around 14psi (call it the "settling point"). I put in a bigger spring and it popped of at around 20psi and settled at 18psi so I decided to try that, as I hadn't identified any real issues. I replaced the diaphram (WSM brand I think) and the diaphram cover and Jay suggested we check the pop-off one last time. With the diaphram cover on now, the needle popped at 20psi again then slowly the pressure dropped to 0. The needle was being held slightly open after a pop-off by the button on the diaphram!!

As we already had a heavier spring our next idea was to bend the needle lifting arm very slightly (like 1mm lower) so the diaphram button would still be touching the arm but not pressing on it. This brought the "settling point" up and we bent it so after the 20psi pop-off, it would again seal at 18psi

Ever since I have not had any fuel flooding issues, the needle seals perfectly so clean starts every time!!

Massive thanks to everyone for the assistance and Jay for helping out and having a good selection of all the spring sizes with labled wheights! I'll post again later with the spring wheights and resulting Pop-off's in my carb.