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  1. #1
    Join Date
    Mar 2021
    Posts
    14

    Default 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?

  2. #2
    Join Date
    Dec 2013
    Posts
    642

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    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?

  3. #3
    Join Date
    Mar 2021
    Posts
    14

    Default

    Quote Originally Posted by CJD View Post
    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?
    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

  4. #4
    Join Date
    Dec 2013
    Posts
    642

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    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.

  5. #5
    Join Date
    Jul 2007
    Location
    Flowery Branch Georgia
    Posts
    2,650

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

  6. #6
    Join Date
    Mar 2021
    Posts
    14

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    Quote Originally Posted by michael hunter View Post
    Does your engine tilt back or is it level? Pics would help.
    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.

  7. #7
    Join Date
    Dec 2013
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    642

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    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.

  8. #8
    Join Date
    Mar 2021
    Posts
    14

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    Quote Originally Posted by CJD View Post
    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.
    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.

  9. #9
    Join Date
    Mar 2021
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    14

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    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?20210517_114955.jpg

  10. #10
    Join Date
    Dec 2013
    Posts
    642

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    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.

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