66 bronco 170 carburetor problem

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socketcap

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Hello I am new to this forum,

I have a 1966 Bronco plow truck for my home with 170 I6 engine and it has the very reliable and simple Motorcraft single barrel carb.

The vacuum fuel pump died several years ago, I bought and installed a 12 volt fuel pump that is internally regulated 2.5 to 4 PSI.

I have had no problems with the carb until this weekend.

The intake manifold has inlet and outlet cooling lines from the water pump.

When I shut the engine off, the carb makes a gurgling sound like there is air traveling through the gas in the float bowl and gas starts dripping from the throttle plate shaft, I had thought for a moment that the internal regulator in the fuel pump died so I disconnected the pressure side of the fuel pump, however the gurgling continued on.

Is it possible for the coolant cooled manifold to get too hot for whatever reason and cause that symptom?

I am trying to think of what I had changed this year and realized that the heater core started leaking badly last fall and I eliminated the heater core by tying the hoses together with a piece of pipe and clamps.

Would removing the heater core from the coolant circuit cause the intake manifold to overheat?

Every 2-3 years I disassemble the carb and clean it and it usually runs good for another 3 years, and I did this cleaning yesterday and the carb ran great for about 20 min or so at which point it sounded like it was dumping raw fuel into the manifold it then stalled and I noticed the gurgling sound coming from inside the carb and fuel was then dripping from the throttle plate shaft again.

I was pondering whether to replace the carb however I don't think the carb has a problem because it runs like a clock for about 20 minutes.

Any help on this would be most appreciated.

I have about a foot of snow that needs to go away

 

BroncoJoe19

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The only thing that I can relate to this story is that I had a lawnmower with a carb problem that surprised me.

If you have taken your carb apart and cleaned it, then you know that there is a float in the bowl that puts pressure on the float valve. When your float is properly adjusted, it should put pressure on the valve to stop fuel from flowing. My guess would have been a stuck or sticking float... BUT... you just cleaned it!

Being that it ran fine for twenty minutes, the float must have been properly adjusted.

OK... so by now I got you wondering... when is this guy gonna shut up and tell me what he really thinks.

The float in my carb was slightly porous (spelling) it had ity bity little holes in it. It VERY slowly filled with gas, until it didn't float enough to close the valve.

Hope this helps.

joe

 

Bully Bob

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"Would removing the heater core from the coolant circuit cause the intake manifold to overheat?"

NO....

Pressure test the pump...and/or closely check the needle & seat.

Meaning.., the reg. in the pump went south.., or the needle & seat have a leak.

On some carbs. you can remove the air horn, engage the pump & watch the bowl fill up...or in fact, over fill.

& yes, it would run OK for a while..with a slow leak.

 

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