Carb Bowl Leaking

Well, no good deed goes unpunished. Our bike lost power at the the high end the other day so I cleaned the carb which fixed the original problem as it is running well. However, the carb bowl drain is now leaking. It runs fine once we get it going but since the bowl empties while it is sitting it is making it hard to start, I think. So, two questions. Can somebody recommend where I can order parts for a dellorto PHMV 12 carb? Any suggestions on a temporary fix while I am waiting for the replacement part(s)? Thanks much.

Re: Carb Bowl Leaking

carb bowl drain leaking?

Does that carb's drain use a pointed screw? If the drain is actually leaking, a mechanical fix should be obvious, like tightening the screw or cleaning it's tip.. or it might be to replace the screw's tiny O-ring, assuming there is one.

But take a close look at the drain. On some carbs, inside the float bowl there is a thin, vertical overflow tube and the drain channel at the bottom does double-duty as an overflow. When fuel level rises above the top of the overflow tube, fuel is channeled down to the drain and drips from the drain tube.

Re: Carb Bowl Leaking

My honda pc50 just started to over flow. I don't know what to do. The overflow drain has been plugged so it overflows threw the top and soaks my airfilter and get everywhere with a high potential for a bad fire. I don't know what to do. I've taken it al apart. It might be clogged I just replaced the gas tank and it is missing the gas filter?!?! Obvious answer? But how do I clean it.


Re: Carb Bowl Leaking

It sounds like the float needle valve is leaking.. Fuel continues to enter the bowl although the float rises and attempts to shut it off.. the level gets way too high and overflows.

I'm not familiar with the PC50 carb but generally the float needle has a plastic Viton tip .. if the tip is damaged (look close with a magnifying glass) a new valve is needed. Or the valve's seat could be damaged and can usually be smoothed out or made round again with the proper little tool.

Or some bit of dirt (rust and crap from the missing fuel filter or screen?) is preventing the valve from making good contact with the valve seat and cleaning will fix it..

in any case, having fuel spilling out of the carb's vent is a bad idea .. could be dangerous like you say.. So i'd do whatever needs to be done to fix the leak and to be sure that any overflow is properly channeled down to the drain tube..

Re: Carb Bowl Leaking

This carb does use a pointed screw with the tip made of a different material than the screw, maybe Viton? I don't believe the drain doubles as an overflow in this carb. I don't recall seeing an o-ring on the drain screw so maybe if it is supposed to have one, I lost it when I was taking the carb apart to clean it. I'll pull the screw and see if there is any obvious place for an o-ring to be. Thanks.

Re: Carb Bowl Leaking

Sometimes my carb bowl leaks because my float has stuck open for some reason. When I open the petcock I usually get the blunt end of a screwdriver and gently tap the float bowl. This vibrates the float a little and it becomes unstuck, thereby regulating the fuel level in the float and therefore does not overflow.

"Dan": taught me that trick after i thought about it for a long time.

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