87 comp carb questions

87 comp ts6m
Holley 4160 carb
350 chevy

Bought recently off some kid who I can tell really didn't know what he was doing, trying to put the pieces back together.

Could tell carb wasn't right from the get go so I had it rebuilt by a pro. Said someone definitely tried to rebuild before, was all wrong.

After rebuild, dropped carb back in... after sitting for a few minutes, engine will fire for a few seconds. Can keep it going for a few extra seconds with throttle, but then it dies. Can see gas dripping into front bores with key off after, won't catch again unless I let it sit for 20 mins and come back to it.

Yesterday, I took the trailer all the way down and it fired right up and idled for about a minute with no throttle. Died out, wouldn't fire back up. Out of gas, I believe... which kind of makes sense that it would run better since I suspect its way too rich.

Today I put a few gallons in and same symptoms as before, might catch for a second or two, gas dripping. Plugs wet and fouled. So much gas I can see the gasket getting wet.

Any ideas where to start?

Which, by the way, not sure I have the right base gasket. The spacer is kind of weird, looks like the gasket should be a square with 1 line down the middle, but I can't find a holley gasket that matches. I have the open square gasket. Questioning whether or not it's even the right spacer, any one have a picture of their spacer?

Open the idle speed up to get it running the first time. You will then have to bring it up to operating temp and adjust the idle mixtures and idle speed. The pro can rebuild a perfect carb, but it still has to be adjusted to your engine. I assume you are running a Holley? If so, start with about 2-1/2 turns open on the mixtures. If it still will not start, then you need to make sure the choke is working properly. Is the choke mechanical or electric?

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Originally Posted by CJD

Open the idle speed up to get it running the first time. You will then have to bring it up to operating temp and adjust the idle mixtures and idle speed. The pro can rebuild a perfect carb, but it still has to be adjusted to your engine. I assume you are running a Holley? If so, start with about 2-1/2 turns open on the mixtures. If it still will not start, then you need to make sure the choke is working properly. Is the choke mechanical or electric?

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I've had them at 1.5 turns and have tried taking them in (tighter)
Does tighter = less gas or more gas?
I'll try 2.5 open anyway.

It's an electric choke, holley 4160

For 95% of carbs, opening the screws is richer. 2-1/2 should be on the rich side, but that is good for initial starting. Once the engine is warm you can work on leaning the mixture to get the most consistent idle at about 650RPM. Try to keep the screws the same number of turns out. If you start altering them individually, you can end up with one bore carrying the engine and the other doing nothing.

For electric chokes, you must know that the choke starts slowly opening from the time the ignition switch is turned on. In other words, the choke has nothing to do with the temperature of the engine, only the amount of time you have the switch in run. If the engine will not start right off, but after sitting with the ignition on for a minute it does, then it implies your choke may be set too rich. Loosen and turn the dial a click or two to the lean direction.

If the above does not help...there is a chance the fuel pressure is too high, so the float is being overpowered. You should be getting no more than 6psi while cranking or running.

Does your engine tilt back or is it level? Pics would help.

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Originally Posted by michael hunter

Does your engine tilt back or is it level? Pics would help.

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Engine is on a slight tilt, front is higher than back
Will get some pics later


Electric choke comment above is interesting to me, didn't know they worked like that. Not sure if it has any real merit, but when it did start up and idle nicely for about a minute, I did have the choke disconnected.

Was it disconnected and held open, or allowed to close? Michael has a great point. The carb can't be tilted too much or the floats will spill fuel out of the vents. Normally the manifold is cut, or an adapter is used to level the carb.

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Originally Posted by CJD

Was it disconnected and held open, or allowed to close? Michael has a great point. The carb can't be tilted too much or the floats will spill fuel out of the vents. Normally the manifold is cut, or an adapter is used to level the carb.

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It was disconnected and in its natural state, closed. I actually just forgot to hook it back up.

There is an adapter /spacer between carb and intake mani. I have to pull the carb off again, but I've got a suspicion it is upside down or backwards or both.. I'll get a pic of that later too.

Okay I went out and checked it out.
Engine is on an angle like I said (up in front)

Spacer in between intake and carb is angled as well to pull the front of the carb down (backside of spacer is taller).

Upon further inspection, the spacer definitely isn't upside down or backwards.

But check out this picture of it. I can tell the gasket isn't right, there's a gap in the middle. Gasket should be square with 1 line through it. The gasket type with the 4 holes won't work here because each barrel wouldn't be flush.

I can't find a holley gasket that matches up with this spacer at all... wondering if its the wrong spacer?Attachment 19608

Summit is the last place I know who carry a good selection of Holley parts. Ace hardware or NAPA do carry gasket material you can use to cut your own gasket if time is a factor.

It's always hard when your following the work of a shade tree mechanic, trying to guess what they left off or changed for the worse.

If it ran for a bit with the choke on, but the choke never opened and it stopped, I think you are in the ball park. With hot wire to the choke hooked up it will gradually pull off the choke, so it should keep running. If it is hard to keep running after the choke opens fully, then try opening the mixtures 1 turn and that should get you running. You will still have to do a fine tune on the screws once the engine is up to temp.

So after letting all the gas inside the intake evaporate with the carb off, I went back to what worked the other day

Trailer all the way down, choke disconnected. Fired up instantly and idled OK. After about a minute, it was about to die off, gave it a little throttle to keep it running. Let it idle for about 5 mins catching it with a little throttle every 30 sec or so to keep it going.

I don't want to get ahead of myself, but seems like the choke is so out of whack that its causing it not to start when connected. I have it set to dead center right now... but when I got it back from the carb guy he had it dead center upside down. Thinking maybe he bent it up.

That adaptor plate is a spread bore, Holley's are square bore. I have never seen a spread bore Holley . I don't know how it will effect the running. Can you take a side pic of the carb and engine to show how much tilt it has . Does it have a 1to1 or a 1.23 to 1 trans if you are not sure send pic of trans.

There are Holley spread bores. They were replacements for the old Rochesters. But so far he hasn't confirmed we are dealing with a Holley.

What happens when you connect the choke wire? Here is what should happen when you have all hooked up correctly:

If you pull the cover after the engine has sat and cooled, the choke will be open.
When you cycle the throttle full forward and back, the choke should set fully closed.
Once you crank and start, the choke will crack about 1/4" from full closed.
Then the choke will slowly move to the open position over about 90 seconds, until full open.

If you do have an electric choke, if you turn the ignition on and have the throttle slightly above idle (engine not started), then the choke should slowly move to open over a 90 second period.

Chokes rarely have to be moved off the center position on the adjuster. One or 2 notches makes a big difference.

Quote:

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Originally Posted by CJD

There are Holley spread bores. They were replacements for the old Rochesters. But so far he hasn't confirmed we are dealing with a Holley.

What happens when you connect the choke wire? Here is what should happen when you have all hooked up correctly:

If you pull the cover after the engine has sat and cooled, the choke will be open.
When you cycle the throttle full forward and back, the choke should set fully closed.
Once you crank and start, the choke will crack about 1/4" from full closed.
Then the choke will slowly move to the open position over about 90 seconds, until full open.

If you do have an electric choke, if you turn the ignition on and have the throttle slightly above idle (engine not started), then the choke should slowly move to open over a 90 second period.

Chokes rarely have to be moved off the center position on the adjuster. One or 2 notches makes a big difference.

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Yes it is a Holley 4160

I'm thinking the choke cap (the adjustable part) is toast. Did some research, they're only supposed to turn to the notches (looks like no more than 45 degrees) in either direction. Any more risks damage to to coil inside. Like I said before, when I got it back from rebuild, it was dead center upside down (turned 180 degrees from center). So it was probably bent wide open, malfunctioning and pouring way too much gas in. Hence why no issue when disconnected.

I have a new one in the mail now

Okay, 100% is a strong number... but I'm almost there believing the new choke cap is going to solve my issue.

I pulled the cap off, and like I suspected it was badly bent out of shape. No amount of proper adjustment opens it up at all.

So, while electric disconnected, I operated choke by hand. Slightly cracked open to start, slowly opened as it warmed up. Idled perfectly.

I think what was happening before was the choke was dead closed and causing the no start. With it disconnected, I'm guessing it was able to cracked open just slightly enough to fire up and run rich.

With the new cap I should get proper operation and should be good to go

Excellent!

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Originally Posted by CJD

Excellent!

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Thanks so much for the help
Feel real dumb for not noticing choke malfunction... but with freshly rebuilt carb that was just so far from my mind