DONR

Well I decided to go on a day trip with a group of car club folks. Car did well going the first 100 miles. I put gas in it about 80 miles back. All of the other cars that filled up at the same place id not have any issues. I thought it could be bad gas. About 20 miles from the 2nd leg of 100 miles the engine died when I pulled up to a stop light. It started right up, but I had to keep the RPM up. Made it home then started checking things out. I checked for vacuum leaks first. No vacuum leaks. Adjusted a little on the carb. I turned the adjusting screws in all the way as well as out about 1 and a half turns. Car would idle a little with the air adjusters screwed all the way in. It still sounded like it was missing at low RPM. Revving it up sounded OK so I checked the points. They were in pretty good condition. No pitting. Dist car had a little corrosion on the terminals inside. Not that bad though. I have thought about putting pointless ignition on it. Might be a good time to.
I have a 327/350HP engine. I do have a rebuilt holley carb. that I think is a 650cfm. The plug wires are not that old. I have not started pulling the plugs yet.
Any suggestions would be appreciated.

Thanks!
Don

anglerjon

Start with the easy stuff, float level, fuel filter, maybe fuel pump. Of course it could be a number of things, just be methodical.

SW Vette

Had the car been sitting for awhile? First thing I'd suspect is contaminants in the gas gumming up passages in the carb. Very common with today's fuel. Disassembly and a thorough cleaning should do the trick. I recommend using a stabilizing fuel additive if the car ever sits for over a month without being driven.

Bowtyeguy

Take a flash light and look in the gas tank and see if you see anything in the bottom. Dirt wise. I would check the easy stuff first. Did you check the dwell? Easy stuff first harder stuff second.

Gary's '66

Can't say as to exactly what the cause is but, I do know that the motor should have died when both A/F screws were bottomed out. If your Holley is stock it should be a 580cfm.

Gary

DansYellow66

My 2 cents from what you describe - I would pull the carb and first use a can of carb cleaner and hose to spray out every passage in it that you can access. Pull the idle mixture screws out and spray those passages out. Then reinstall and see if that did any good. If not then I would pull it and remove the fuel bowls and inspect the needle and seats and spray out all the internal passages. If something looks suspect then get a rebuild kit and replace everything and set the adjustments according to the instructions. Buying a set of those blue, re-usable bowl and metering plate gaskets is also worthwhile if you need to take it apart again.

Forgot to mention to protect your eyes and anything fragile from the spray carb cleaner - it can eat up some stuff and you don't want it in your eyes. You never know sometimes where it will exit a carb when spraying into a passage.

Gary's '66

Gary

66BlkBB

What model carb do you have on the car. My car did the same thing last year. I parked it until this spring. When I went out to start it, it would not fire. When I turned it over the fuel was pumping out of the secondary horn with each pump from the fuel pump. Tore the carb apart and found one of the plastic floats in the carb was half full of fuel. Mine is a 4776 Holley.

survivor66

Simple stuff first... is your gas cap vented? If not, that could cause your symptom of difficult idle after long drive. Even a slight vacuum in gas tank will fight the fuel pump. Don't ask how I know.

tbarb

I agree with this post.

From your description it sounds like the engine is getting fuel from somewhere it's not supposed to. It can be a gasket, metering block to body or throttle body to main body.

Also, don't rule out the power valve gasket, manifold vacuum can pull fuel here also. The sure sign it's getting fuel from somewhere is the emulsion screws turned in and the motor still runs.

DONR

survivor66 - Seems like the gas cap is vented OK. Have not checked the fuel pump. Since plenty of gas was in the gas filter when I took it off makes me think that the fuel pump is OK. I do have another one ordered though.

66BlkBB - Good idea to check the floats to make sure they do not have a leak in them. Need to take the carb apart.

Gary's '66 - I to was surprised when the air mixture screws was turned in all the way and I could get the car to idle fair with advancing the idle screw up a little more.

DansYellow66 - Good idea I will start trying to clean the carb passages. It has been a while since I had a Holly carb apart, but I think I can do it OK. Thanks for the tip on buying a set of those blue, re-usable bowl and metering plate gaskets.

Bowtyeguy - The gas tank was replaced about 15years ago. I looked in it and it appears to be clean no sediments in the bottom. Have not checked the dwell yet. That is on my list to do.

anglerjon I did check the float level. Took the side screws out after shutting of the car. There was no draining of gas out the front float bowl or the back float bowl. Have checked the fuel filter lots of gas going through it.

SW Vette - Gas cap seems to be vented OK. The car has not been sitting long since driven last. My next step will be to start taking the carb apart.

Thanks for everyone's help so for. I will check the stuff suggested that I have not done yet and let you all know what I find.

Don

DansYellow66

Something else I forgot to mention is picking up a can of 3M Gasket Remover. The old stuck on old gaskets won't exactly melt off but it does soften them up enough where they can usually be scraped off with a plastic scraper.

63FI

Take a look at one of your plugs. Is it dark, carbon coated? If not, no need to read any further. If yes, what are the size of your primary jets in carb? If you are saying your bleeder screws are in all the way, something is making the mix rich, like too large jets or a stuck float maybe. Primary jets size for 300HP stock 327 is 62-66.

DONR

I have not looked at the plugs yet. Maybe next step. My carb is a remanufactured Holley number 65-1850S, which I think is 600 CFM.

LouieM

That happened to me once after buying bad gas. The car started but would only run at high revs. The fuel filter was clogged and a new filter solved the problem.

Gary's '66

I would also check the filter as well however, he must REALLY be unlucky as he mentioned that a bunch of other cars filled up at the same station.

Gary

DONR

I put new points and spark plugs in over the weekend. Still missing at low RPM. Will rev up fine. I pulled the carb off. Down in the intake there was lots of raw gas. It did appear that gas was leaking down into the carb barrels. My float levels were level. I have 65H primary jets.
I guess I will get a kit and rebuild the carb.
on the face of the carb it is stamped 8C457-2 under that says 2911 I think. My engine is a 327 350HP. Still not sure what size this carb is. I know it is not original it is a rebuilt carb. There is a sticker on it with H61850S then says Holley Remanufactured and under that it has 65-1850S.
Thanks for everyone's help so for. I will keep you posted.

Vet65te

The original Holleys for 66 smallblocks were about 585 cfm while the generic replacement #1850 is around 600 cfm so that's a wash. The #1850 out of the box doesn't come with a divorced choke while the #3367 would have had a divorced choke setup. The jetting is about the same too.
Mike T - Prescott AZ

DONR

Plugs were pretty black and carboned up so I replaced them. I read a little more about the Holley Carb. They mentioned that the Power Valve can go bad. Well I went and got a new power valve at the local parts store and put it in. I think that was the trouble. It idles now. I did put a new set of points in it too. I could not find any 3M gasket remover. I saw where an old mechanic used WD-40 so I used it on the gaskets.
I do seem to have a small miss at low rpm. I need to check the dwell with a dwell meter. Not sure on the timing. I have several marks on the harmonic balancer. One I think at 0 and 3 down the pulley a little ways. I did the timing by where it seem to run best. I took it out. It runs great at high speeds.

DansYellow66

That sounds like an improvement. If you can't get rid of the miss you might check the plug wires. If older, removing and reinstalling them may have damaged a terminal crimp, wire conductor or something.