MORE CARB ISSUES PROFORM 850 DP

Frankb · Dec 19, 2020

I've been having problems with my Proform 850 racing (no choke) series carb. Its been on the car for about 7 years but only has about 1500 miles on it. I've had some issues a few months ago and got all but one problem fixed. Fuel discharges from the secondary boosters when fuel pressure is applied. When I take the bowl off and apply air pressure and manually lift the float the air stops. Valve and seat look good. I'm going to assume float level is still good. Its never been adjusted. I know I should assume nothing but with fuel pressure applied when carb is on the engine gas is just being pumped into the manifold and into the engine. Should I just replace the needle and seat assembly anyway?

Jeremiah · Dec 19, 2020

Make aure the float floats.

65-440 · Dec 19, 2020

Jeremiah said:
Make aure the float floats.

YES !!!! But also, where is it dumping into the engine from, bowl vent or squirter ? Is the pendulum there underneath the squirter ?

Frankb · Dec 19, 2020

The float is good. I submerged it for 10 minutes and compared the before and after weights. 302 G before and after. Fuel is dumping from the secondary boosters, not the squirter. Whats the pendulum?

65-440 · Dec 19, 2020

Frankb said:
The float is good. I submerged it for 10 minutes and compared the before and after weights. 302 G before and after. Fuel is dumping from the secondary boosters, not the squirter. Whats the pendulum?

The pendulum is underneath the squirters. Without it fuel would constantly dribble out of the squirter nozzles.... sure you don't have too much fuel pressure?

Frankb · Dec 19, 2020

65-440 said:
The pendulum is underneath the squirters. Without it fuel would constantly dribble out of the squirter nozzles.... sure you don't have too much fuel pressure?

I didn't check pressure but primary side is good. Fuel is not coming from the pendulum. There is a hole in each booster and its discharging in equal amounts from each booster. I think I'm just going to buy a kit and go through the carb. Thanks for your help.
Frank

RemCharger · Dec 19, 2020

7 years is time to chuck a fresh kit in. Sometimes the needle oring rots out. Take a good look at the tiny emulsion holes in the metering blocks.

65-440 · Dec 19, 2020

Frankb said:
I didn't check pressure but primary side is good. Fuel is not coming from the pendulum. There is a hole in each booster and its discharging in equal amounts from each booster. I think I'm just going to buy a kit and go through the carb. Thanks for your help.
Frank

True, high pressure would affect both sides. Tear it down and clean it out !

MORE CARB ISSUES PROFORM 850 DP

Frankb

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Jeremiah

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65-440

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Frankb

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65-440

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Frankb

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RemCharger

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65-440

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