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jazzmaster
jazzmaster, Classic Car Mechanic
Category: Classic Car
Satisfied Customers: 2951
Experience:  ase certified--32 yrs experience
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Chevrolet Caprice: have a 69 caprice 427,tuned up ,new fuel

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have a 69 caprice 427,tuned up ,new fuel pump,water pump,clutch fan ,thermo,all hoses,alt.,flushed system .car ran fine for months,had grease job done and ujoints checked,mechanic put points in and said i needed a curve kit and carb is original,he said he put a intake carb gasket in that wasnt exactly the right one but fit .car ran fgine for 6 weeks ,now the car is hard to start and hold idle ,stalling out and running rough with some backfire.cant get out of park.did try to clean carb,it was black!checked plugs,removed paper filter from carb;car has ac in line fuel filter that they put on big blocks,which also is new.HELP!

hi,my name is XXXXX XXXXX I will help you ..

do you mean the carb gasket ? was not exactly the right one ?

with the carb getting black/soot in it and not running right point to a big vacuum leak issue

Customer: replied 4 years ago.


hey jazzmaster,that is correct carb gasket wasnt exact for factory q-jet,but he said it would work,and it did as car rar fine for approx.6to7 weeks.took it on a few long trips[100+miles]no problems,again he did say distributor needed curve kit ,but my intentions were to upgrade intake manifold[weiand stealth dual plane]carb[holley street avenger 870cfm] and dist.[pertronixs flame thrower 11 with matched coil]next month already got price from summit racing with all gaskets ,brackets and fuel lines,also new holley 80 fuel pump,thanks john m.

well I think that would take care of any issues you have but as for now it seems to be a vacuum leak ..you can try spraying carb cleaner at the carb base and intake and see if you can see any changes in the running ,even checking the air/gas mixture screws ,these should be about 3 1/2 turns out .also check the dwell it should read around 30 gegrees ..jazzmaster ...
Customer: replied 4 years ago.


did try cleaning carb with gumout carb cleaner.followed directions and cleaned exterior good then started up and sprayed into carb,didnt help at all .how would i check for vacuum problem besides checking condition of hoses,thanks jazz.john m.

you should spray a little at the base of the carb ,and the intake gasket -where the intake meets the block and also need to check the dwell which should be at 30 degrees the dwell is the fine tuning of the points ,if the distributor cap has the metal door in it then you can adjust that there with an allen wrench.,if the points are out a bit ,it will give the symptoms that you have as well.

and please do check the air/gas mixture screws as well ..jazzmaster ....

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