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carburation issue...

Posted: Sat Mar 19, 2022 2:59 pm
by investig8
Hello,
Well, was taking Fiona out to a car show this morning and she died at an intersection and wouldn't restart. Finally got her started and out of traffic but she would barely run, the plugs / carburetor was loading up at lower RPM. I could rev it up and "blow" it out and the engine would level out without missing but as soon as the RPM falls she began to load up again terribly. I checked the choke butterfly to ensure it had not slipped out of position but it was fine and tried new plugs to no avail. I have put an electronic module on it so I don't think it has anything to do with ignition. She has been running wonderfully up to this morning. I'm thinking I just need to replace the carburetor (which I never did) because it sat for so long before I got her... Any other recommendations??
Thanks again for being there...
Dennis

Re: carburation issue...

Posted: Sat Mar 19, 2022 3:30 pm
by greeno
What did the old plugs look like?

Re: carburation issue...

Posted: Sat Mar 19, 2022 4:02 pm
by investig8
Sorry, should have mentioned that... Plugs were heavily, black sooted, which means way to rich, right? Additionally, the idle screw has never had any effect on the way she idled, hence the thought that I need to rebuild / replace the carburetor.

Re: carburation issue...

Posted: Sat Mar 19, 2022 6:17 pm
by refit1701
If she's running rich I'd check the float level.

If the idle mixture screw isn't working, she may be idling too fast. These trucks idle at about 500 rpm and it always sounds slow but the mixture screws effectiveness fades out at 20 mph or so and the high speed circuit takes over.

Re: carburation issue...

Posted: Sat Mar 19, 2022 6:53 pm
by investig8
Thanks for your help, I agree that its just getting way too much fuel. I will check the floats and go from there...
Dennis

Re: carburation issue...

Posted: Sun Mar 20, 2022 7:35 am
by EDM43
i was going to say...sounds a lot like a stuck float.

Re: carburation issue...

Posted: Sun Mar 20, 2022 2:56 pm
by NAM VET
good info on this forum about how best to adjust a float. Agree yours is not precisely metering gas flow. Get a carb gasket set from one of the vendors, cheap. I posted some thoughts about How I did mine recently with pics. NV

Re: carburetor issue... HELP

Posted: Fri Mar 25, 2022 10:52 am
by investig8
OK friends,
As you remember, my truck died at an intersection last week and I had to have her towed. With your help, I confirmed that the issue was a float issue in the carb. The carb was the original on the truck with a maintenance tag that it was rebuilt in 1974. I decided to just replace the carb and got one from Midwest. When I went out to pull the old carb the truck had sat for three days. Fuel was dripping out of the butterfly device where the two manifolds bolt together. I disconnected the fuel line and removed the old carb to find a small puddle of gas sitting in the bottom of the intake manifold. Today I installed the new carb and decided I needed to check the oil since it seemed a lot of fuel had been in the intake and running out. Sure enough, I drained a couple gallons of fuel/oil mixture out of the pan.

Now, the big question is: The fuel pump was installed new about a year ago and I haven't run the truck a heck of alot since so I don't believe the diaphram would already be leaking by. I think the fuel must have been what continued to overflow in the carb because of the float issue. Oh, a contributing factor may be that my driveway is relatively steep, and she was parked with the rear uphill, which seems to me it set up a gravity feed past the float to the pan... I'd like to hear your thoughts as well as the best way to "dry" the block out before trying to start it again...
Always something, right?
thanks as always,
Dennis

Re: carburation issue...

Posted: Fri Mar 25, 2022 6:20 pm
by PoW
An oil/filter change will do for the contamination.

My advice is get rid of the mechanical pump and put in an electric back by the tank, and route the fuel line away from the engine everywhere possible.

New gas destroys rubber parts fast, and that is all we have to run nowadays.

PoW

Re: carburation issue...

Posted: Mon Apr 04, 2022 6:26 am
by investig8
Good News! After a messy oil and filter change (who knew the viscosity of gas/oil is thinner than oil) LOL! Needless to say, I missed the drain pan! At any rate, once completed and a rebuilt carburetor was installed, Fiona once again runs like a sewing machine! As I read on another post, "it's always something!"
Thanks for the help and recommendations,
Dennis

Re: carburation issue...

Posted: Mon Apr 04, 2022 8:41 pm
by Cal_Gary
That IS great news Dennis-congratulations!
Gary