carb issues - hard/impossible start warm

Lincoln M · Post by **Lincoln M** » Tue Feb 21, 2006 11:02 am

1981 spider 2000 w/2000cc engine 5spd shift
but, unsure what year the engine is, the FI was swapped out and this other one put in.

It's got an Autolite 2bbl carb (from a pinto I'm told) and uses points ignition.

I removed the water choke assembly and put a manual choke lever on to help with some issues/guessing.

Seems to start up and run fine cold, and runs fairly well warm although if I keep the choke out it runs better than letting it in when warm.

It's like if the choke is in, I get great response and power when I floor it, but it's horrible for feathering/normal driving. With the choke out, normal driving seems great, but flooring it bogs down.

My biggest problem (so far) is once she's nice and warmed up, if I park it and let it sit for about 5 minutes, I may not be able to get it started again until the engine is completely cooled. This may mean sitting still for 20-30 minutes.

I have rebuilt the carb and replaced one inline fuel filter between the pump and carb.

Any suggestions from here on what to do?

On my list are:
- try to do plugs/points/roto-cap replacement (will have to guess the year of the engine for this)
- look for any other fuel filters between the tank/pump and replace
- check fuel line pressure (warm and cold)
- find a replacement carb (mayhaps a webber, depends what I can get)

Thanks,
Lincoln

So Cal Mark · Post by **So Cal Mark** » Tue Feb 21, 2006 3:26 pm

the Pinto carb is a decent upgrade, it has 36mm secondaries instead of the 34mm on the oem carb. It sounds like you have 2 different issues going on. jetting may be wrong or you have a vacuum leak causing a lean condition off idle. The no start hot could either be that the fuel is running into the venturi and flooding the engine when hot, or the fuel is leaking out and the float bowl is empty. If the accelerator pump is leaking it will drain the bowl and also cause a hesitation accelerating from a standing stop.

Lincoln M · Post by **Lincoln M** » Wed Feb 22, 2006 10:42 am

Thanks again, Mark.

Since I've already rebuilt this carb and still have problems I'm going to likely start by trying to find a replacement. The pinto carb sure doesn't seem like a high quality piece of machinery

The bolts holding down the top carb plate seem prone to causing warping which may be my problem on this carb (hence possible vacuum leaks).

Couple more questions then:
- what year pinto (or other ford) has the most appropriate carb to fit the fiat?
- are there any mandatory changes to the carb to get it running on a 2000cc?

Cheers,
Lincoln

So Cal Mark · Post by **So Cal Mark** » Wed Feb 22, 2006 3:33 pm

I'm not sure what years Pinto used those carbs, they're pretty much a direct bolt on. You may have to change the throttle arm on the carb. Even a warped top shouldn't cause a no-start. I think before replacing the carb you should try to determine the no start issue. Is the engine flooded or starving for fuel? Otherwise you may find that spending the money on a new carb didn't cure the problem
I did find out this morning that the new Weber 32/36 carb is available again

Lincoln M · Post by **Lincoln M** » Wed Feb 22, 2006 4:46 pm

I do remember from when I ran the car last summer and had the no-start when warm issue, I would of course pull the air filter and check for accelator pump fuel delivery.

At those times, the stream may not have been beautifully strong, but it certainly was delivering lots of fuel.

My rebuild of the carb was a standard carb kit which included everything but the carb body.

The top plate gasket did leak before (vacuum leak where spraying carb cleaner on the edge would cause the engine to stall at idle). After the carb rebuild I didn't notice the same leak at the gasket, but I did notice I still had to tighten the top plate carb bolts from time to time.

I'm thinking to still look for a used pinto carb from a wrecker since I shouldn't be paying more than $50 for it, and it will at least give me something to compare to.

So what do you think, since I know I get accelerator pump fuel delivery and it still wont start warm, likely to be a flooding issue?

Thanks,
Lincoln

So Cal Mark · Post by **So Cal Mark** » Wed Feb 22, 2006 9:31 pm

I'd check for flooding, remove the air cleaner once the engine is off and look down into the venturi for fuel puddling on the throttle plate

noneedforanintroduction · Wed Mar 08, 2006 10:08 pm

72-74 Pinto and Mustang 2

question... what type of fuel pump are you running? Mechanical or electrical?

If electrical, is it a puller pump in the engine compartment, or a pusher in the trunk? If it's not a pusher pump in the trunk you're suffering from vapor lock, where the heat from the engine evaporates all the gas in the carb, leading to hard starting issues.

(been there, done that, cured the problem with a pusher pump)

So Cal Mark · Post by **So Cal Mark** » Thu Mar 09, 2006 1:14 am

I'm not aware of any electric pump that is a puller. By design, they all push much better than they pull

Lincoln M · Post by **Lincoln M** » Thu Mar 09, 2006 1:39 pm

mechanical pump.

it's possible it might be leaking as it looks a bit wet.

anyone know fuel pressure levels that I can check for?

Thanks,
Lincoln

So Cal Mark · Post by **So Cal Mark** » Thu Mar 09, 2006 3:29 pm

that mechanical pump only needs a couple of lbs of pressure to work, wetness around the pump isn't a good sign

mdrburchette · Post by **mdrburchette** » Thu Mar 09, 2006 5:19 pm

I checked the fuel pressure on my mechanical and got 5 lbs at idle and up to 7 lbs while cruising.

So Cal Mark · Post by **So Cal Mark** » Thu Mar 09, 2006 6:48 pm

mama mia! that's one beefy pump!

mdrburchette · Post by **mdrburchette** » Thu Mar 09, 2006 7:58 pm

Thank you.