Leaking Needle Valve - Brosol/Solex Dual Carbs H32/34 PDSI-3

[BellePlaine]

I drained the gas from bowls of my aftermarket carbs for winterizing. Each carb has a drain plug so I got a little glass jar and drained the driver's side carb first. The gas ran out of the bowl and stopped flowing after a 20 mls or so. Then I proceeded to do the same to the passenger's side carb, only this time after the main rush of gas, the gas would continue to trickle out. Puzzled, I replaced the drain plug to contemplate the situation later.

My first thought was that my passenger side needle valve is leaking, but now I'm thinking that it's probably not leaking because the float was obviously not closing the valve thus the valve was working properly. But then does that mean that my driver's side valve is faulty because it was not letting gas in to refill the bowl?

Are my needle valves operating properly?

[RSorak 71Westy]

Normally the fuel is feed to the carbs under pressure. You were testing them without any pressure and using gravity flow.....Now do you understand the results you saw?

[BellePlaine]

Normally the fuel is feed to the carbs under pressure. You were testing them without any pressure and using gravity flow.....Now do you understand the results you saw?

Right, the fuel was flowing using gravity and the pressure of a full tank of gas. No, I still don't understand why one bowl drained it's gas and stopped and the other continued to dribble.

Also, I'm concerned that if gas is trickling out without the use of a pump, isn't that a fire hazard?

[chitwnvw]

Also, I'm concerned that if gas is trickling out without the use of a pump, isn't that a fire hazard?

Sure sounds like it would be...

[Amskeptic]

Normally the fuel is feed to the carbs under pressure. You were testing them without any pressure and using gravity flow.....Now do you understand the results you saw?

Right, the fuel was flowing using gravity and the pressure of a full tank of gas. No, I still don't understand why one bowl drained it's gas and stopped and the other continued to dribble.

Also, I'm concerned that if gas is trickling out without the use of a pump, isn't that a fire hazard?

It is up to all kinds of physics as to why one carb would dribble and the other would not. If I were in your situation, I might tap the inlet of the carb that quit, to see if that started it. Then I would take the hoses off the carbs one at a time to see if there is a different fuel supply to each carb. Sometimes, just the loop of hose promotes a siphon effect while the other hose does not.

As far as the engine is concerned, it likes having fuel available at the inlets, and it relies on the needle valves to stop the flow. The fire hazard is that gasoline exists. You make sure to control it within the engineering solutions that have worked well for over a half a century.
Colin

[BellePlaine]

For now, I've placed a sticky note on the engine hatch to investigate come Springtime. Thanks for all of the advice.

[chitwnvw]

For now, I've placed a sticky note on the engine hatch to investigate come Springtime. Thanks for all of the advice.

Yes, the winter honeydo list.