[pastorpete]

Double ?’s.
Resurrected an 88 250r. Tank leaked where the petcock and tank meet. I removed the petcock and the tube and screen completely dissentigrated. I cleaned it all, slapped an O ring on it and everything sealed perfect. No on/res function, just on/off.
Carb problem. I cleaned the carb really good and it spews fuel out of every overflow tube. Cleaned, soaked, blew out more times, still the same. Swapped a known working 87 carb, same thing. It’s like a stuck float.
Question. With there being no tube or screen for the petcock, could the gravity pressure of the fuel be forcing the needle open? Could I just have two bad carbs (second one was perfect last fall). Help!

 

[jdp]

Welcome, I'd get a new petcock cause there has to be some fuel resistance from the filter screen or it could do what your saying, or the needle isnt sealing on the seat.

 

[retro]

Its probably just a coincidence that the 2nd carb acted the same as the 1st, or it possibly was fed a particle from the tank due to the screen missing. To answer your question, no, the missing petcock screen does not add any additional fuel pressure to the supply. The head (pressure) is the same as it ever was... its dependent on fuel level height inside the tank only.

 

[SamUK]

I had a similar issue with a trx250a carb (very similar carb), time after time the carb leaked out the overflow. It was the needle valve that the float shuts off. I ended up cleaning about 10 times before it came right.

Edit, last time I cleaned I fitted a new float also.

 

[SamUK]

Sorry, I may be wrong about the 250r carb being similar to the 250a, I misread your post and thought this was a BR250.

 

[fishfiles]

I would guess you have crude in the petcock and or the tank and are putting grit thru the carb float needle valve and causing it to stay open

 

[pastorpete]

Thanks for the replies. I will flush and flush and flush the tank/petcock again and clean/blow out the carb also.
Never to old to learn something new.....
Thanks.