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Discussion Starter #1
Hello, first let me say the carb and ignition system work great when warmed up and will start easy all day and the next day once its been running.
If I let it sit for 3days or more I have to turn the engine over for 30 seconds to allow the fuel pump to get gas back into the bowl. These rochesters boil out the gas I'm told and I do have some stains on the intake manifold where gas drips out of the throttle shaft after I shut it off. Then pump it a little or choke it (Manual Choke) a little to get it to fire. It starts running on 4-5 cylinders and will kick another cylinder in every 15-20 seconds. After two minutes of running like crap its finally hitting on all 8 cylinders. I thought I could confirm it was a fuel problem by spraying in Starting Fluid while it was missing out and expected it to fire up on all cylinder, it continued to sputter for a couple minutes. So I'm looking for suggestions. Is it fuel or something else. It has a new kit in the carb about 6 months ago. Would an electric fuel pump help with this problem, the manual pump is 2 yrs old. All ignition parts are new in the last two years and they work well after it gets warmed up so don't think the problem is electrical. Thanks for any suggestions!
 

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Hello, first let me say the carb and ignition system work great when warmed up and will start easy all day and the next day once its been running.
If I let it sit for 3days or more I have to turn the engine over for 30 seconds to allow the fuel pump to get gas back into the bowl. These rochesters boil out the gas I'm told and I do have some stains on the intake manifold where gas drips out of the throttle shaft after I shut it off. Then pump it a little or choke it (Manual Choke) a little to get it to fire. It starts running on 4-5 cylinders and will kick another cylinder in every 15-20 seconds. After two minutes of running like crap its finally hitting on all 8 cylinders. I thought I could confirm it was a fuel problem by spraying in Starting Fluid while it was missing out and expected it to fire up on all cylinder, it continued to sputter for a couple minutes. So I'm looking for suggestions. Is it fuel or something else. It has a new kit in the carb about 6 months ago. Would an electric fuel pump help with this problem, the manual pump is 2 yrs old. All ignition parts are new in the last two years and they work well after it gets warmed up so don't think the problem is electrical. Thanks for any suggestions!
Id look for another carb, They shouldn't be hard to find, almost no one will consider driving a chevy without a 4 barrel. (don;t know why)

IF you can;t find a carb, I would suspect you need an overize throttle shaft or bushings to take up the slop. You should also have a non metalic riser block under the carb to keep the heat from boiling out your fuel bowl after shutdown. Check the intake and carb base for vacuum leaks.

Does it put out smoke while it is picking up speed running on 4 then 5 then 6? You might have a problem with oil running down the valve stems (Bad valve seals) and fouling out the plugs after sitting, Fords were worse about that, but chevys can have the problem too. Let us know what you find out.

PS welcome to another missourian.
Gary
 

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Hey Gary, thanks for the suggestions, and good to chat with a fellow Missourian. I've never really checked that close for smoke from the tail pipe, but was starting to think stuck valves or flaky lifters. I think I'll let her cool down a couple days ...just did a 50 mile cruise...and then pull the plugs before I start er up and see what each cylinder looks like. Maybe even pull a valve cover and watch the rocker action.
I have considered swapping out to a 4 bbl, it looks like intake manifolds are pretty cheap, but carbs vary a lot. I kind of like the stock look for air cleaner so would like to find something that looks original. But on the other hand don't want an old carb like these rochesters. Any one have a recommendation on a NEW carb that is dependable yet reasonable priced? This is not a hot rod truck so don't need a big Holly..

Thanks for the input.

Roger
 

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Trifive Automotive Electrical Wiring Expert
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Your on the right track when you mentioned fuel boiling out of the carb. I don't think pulling the plugs or putting larger throttle shafts in will do anything. The fuel in the carb is getting hot when you shut it down for a while, running down the intake and fowling the plugs. That's why it misses until the plugs are cleared and why the carb bowl is low on fuel. A thick an insulator/spacer under the carb will do more good than anything, to keep the heat from the block from heating the carb.
 

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Hey Gary, thanks for the suggestions, and good to chat with a fellow Missourian. I've never really checked that close for smoke from the tail pipe, but was starting to think stuck valves or flaky lifters. I think I'll let her cool down a couple days ...just did a 50 mile cruise...and then pull the plugs before I start er up and see what each cylinder looks like. Maybe even pull a valve cover and watch the rocker action.
I have considered swapping out to a 4 bbl, it looks like intake manifolds are pretty cheap, but carbs vary a lot. I kind of like the stock look for air cleaner so would like to find something that looks original. But on the other hand don't want an old carb like these rochesters. Any one have a recommendation on a NEW carb that is dependable yet reasonable priced? This is not a hot rod truck so don't need a big Holly..

Thanks for the input.
Roger
Roger,
I agree with Acardon above, Of all the things I mentioned, The spacer is probably the most important. The rochester 2GC is as good a carb as was ever built, but it needs to be adjusted right and not leaking. I see no reason to go to the expense and trouble of a four barrel if you can work the bugs out of your setup.
If you get stuck and feel like a cruise bring it up here and we can figure out whats going on. Ive got a 2GC on my 55 and another one on a 56 engine in the shop. Ive rebuilt alot of them over the years.
Gary
 

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Discussion Starter #6
Ok, thanks guys. I'll check with my local parts place this week and see if they have an insulator for the carb. If not I know I've seen them on Ebay.
While we are on the heat topic for carbs, when I put on the intake manifold a couple years ago, the instructions said to leave the exhaust manifold ports to the base of the carb open on both sides for a 56 265 engine. But some later models had various ports covered or restricted with a small part included in the kit. So just curious if thats right or maybe I'm cooking my carb with all that exhaust heat? I'm guessing it needs some heat for those cold winter days but I've been known to mess up on "instruction" before so just want a second opinion.

Roger
 

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Also make sure the heat riser valve is not sticking or frozen partially shut it will cause carb overheating if it is.

Regards, Robert
 

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It didn't have a heat riser on it when I bought it, and when I asked a friend he said don't waste your money on one. So I havn't ...yet.

Good idea though. Thanks.
 

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It didn't have a heat riser on it when I bought it, and when I asked a friend he said don't waste your money on one. So I havn't ...yet.

Good idea though. Thanks.
The heat riser will primarily help the car heat up faster in the winter. Since you don;t have one, you should be good to go.
 

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I'm not an expert on these carbs but do they have the lead sealed plugs in them that the Quadrajets have? They have been known to leak when they get older. I've had to epoxy (w/ JB Weld) over them to seal them in a few older carbs. Good luck with you problem!
 

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I couldn't find the insulator gasket local, so am bidding on an ebay item to test that theory. So it could be a while before I can tell if it works.
As far as the "Plug" I have another 2GC on the shelf I can look at it if you can give me a general area to look in. Maybe some of the experts can answer the plug question as well.
 

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I couldn't find the insulator gasket local, so am bidding on an ebay item to test that theory. So it could be a while before I can tell if it works.
As far as the "Plug" I have another 2GC on the shelf I can look at it if you can give me a general area to look in. Maybe some of the experts can answer the plug question as well.
Roger, The plug issue is a problem with quadrajets, I don;t think it applys to 2GC's Ive never heard of one anyway. If you have an old one setting on the shelf, You might consider rebuilding it and trying it instead. Have you ever rebuilt a Carb?
Gary
 

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I couldn't find the insulator gasket local, so am bidding on an ebay item to test that theory. So it could be a while before I can tell if it works.
As far as the "Plug" I have another 2GC on the shelf I can look at it if you can give me a general area to look in. Maybe some of the experts can answer the plug question as well.
Check with Larry @ AUTOMOTION - www.HotRodCarbs.com he offers a whole bunch of stuff specific to the Rochester 2-Jet, and an Insulator Gasket is available -

http://www.hotrodcarbs.com/parts.php?Carburetor_Parts&page=3
 

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