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Carburetor Question

Pegasys

Well-known member
Joined
May 17, 2002
Messages
48
Location
Toronto, Canada
Corvette
1973 Red Coupe
The person I bought my 73 Vette from left it for 2 years without driving it (well ok, $10.00 spent on gas in 2 years). When I start up the car, for the first 3 minutes or so it's sluggish and if I accelerate too fast, it backfires. Once I get going - it's a dream...quiet, smooth etc.

Here's the question...do I need a carb rebuild ($300 Cdn), or should I try a carb cleaner first and see how that goes?

Thanks gang....

Mike
 

Tom Bryant

Well-known member
Administrator
Joined
Nov 9, 2000
Messages
7,322
Location
Edgerton, Ohio, United States
Corvette
1959 black 270hp (9/2/69) 1981 Beige L81(10/20/80)
I've had good luck with Seafoam which is available at NAPA stores. I would try the cleaner you add to your fuel tank for a few tanks. If it desolves the varnish and gets things running well you have saved $300.

Tom
 

Pegasys

Well-known member
Joined
May 17, 2002
Messages
48
Location
Toronto, Canada
Corvette
1973 Red Coupe
Tom, The Seafoam just pours into the gastank? Is it a gas line cleaner?
 
B

Big Fish

Guest
You know it's possible you might not have a carb problem at all. If the engine has been modified at all the heat rider passages through the intake manifold could have been intentionally blocked off to prevent discoloring and hot spots on the intake manifold. This won't hurt a thing, just causes slower than normal warm up time. Try just letting the car run at a fast idle until you get to 160 degrees or so, than drive. Sounds like it runs OK once it warms up?
 

Pegasys

Well-known member
Joined
May 17, 2002
Messages
48
Location
Toronto, Canada
Corvette
1973 Red Coupe
Big Fish,

It does run very smoothly and quiet after I drive it for a few blocks or so..?
 
B

Big Fish

Guest
You know what the old saying is: If it works, don't fix it. If you are planning to drive it in the winter you will probably have trouble however (that is if the heat riser is blocked)
 
P

page62

Guest
It could also be a malfunctioning choke. But not a carb rebuild...
 
S

Stryker_78

Guest
Canadian Tire has an awesome product that I used to clean up my carb a couple of weeks ago. I will check to see what it is called. It takes off all of the carbon. Quite nice. :) Carb runs better now. :)


Scott
 

Tom Bryant

Well-known member
Administrator
Joined
Nov 9, 2000
Messages
7,322
Location
Edgerton, Ohio, United States
Corvette
1959 black 270hp (9/2/69) 1981 Beige L81(10/20/80)
Big Fish could be right about the heat riser passages being blocked. Also check your choke operation as has been suggested. The Seafoam pours into the tank. See what Scott comes up with too. There are several good fuel system and carb cleaners out there. You sure won't be out much by trying one.

Tom
 
7

78SilvAnniv

Guest
$300 to rebuild?

I had a mechanic friend rebuild mine...for the cost of the kit. $16.00.
Sil
 
R

RustyVette

Guest
78Silv,

You mind sharing the name and address for your mechanic friend??? We could all use one of those.

Rusty
 

Pegasys

Well-known member
Joined
May 17, 2002
Messages
48
Location
Toronto, Canada
Corvette
1973 Red Coupe
I just bought 2 bottles of Motomaster Carb cleaner (removes carbon as well) from Canadian Tire. I poured 1 in the gastank to help clean the whole fuel system and this weekend I'll try the more optimal pour it into the carb technique as suggested by the manufacturer. If this still doesn't work...I guess I'll check the choke and if that doesn't work, I'll either be patient when I start in the morning, pray hard, or um... is there another choice???

Mike
 
7

78SilvAnniv

Guest
Mechanic friend

Is shop foreman at a Dodge dealership, and works mostly on newer vehicles, but has professionally raced motorcycles and is interested in anything that goes fast!
He has a '91 Honda CRX that is tricked out, looks like a ricer to me, but it runs great, has plenty of power and he is rebuilding it for MORE power! I think he's shooting for 400-500!? I think it's overkill, but its what he likes.
I could ask him if he'd like to do sidework, but I know I preferred having him at my house doing the carb, so after installation he could check it out right away on the 78. There were a few things he had to adjust, but the 78 SCREAMS like never before! (I think that says alot, considering she was a 170hp vette)
Kenny and I met him at the RV park last year where we were staying waiting for our house to close and their house was being built. They moved in first, had us over for weekend BBQs and saved our sanity! That RV got tiny!..and we were in it for almost 3 months, with a bunch of kitties!
I'll let you know what Chris says to sidework...
Heidi
 
S

Stryker_78

Guest
Ok Mike, this is what I used on my carb. It is called: "Revive": Engine Revitalizer. I sprayed it all over the carb and it disolved all of the buildup. I blew it down into the carb and it was wonderful in there aswell. :)

It can be found at Canadian Tire.

It is in the same section as the carb cleaner that you used and is in an aerosol can. Cost me $7.99 a can I think. 1 can should do ya.

Scott
 
S

Stingray72

Guest
Check your choke pull-off vacuum canister. It's located behind the choke. Disconnect the vacuum line from the inlet on the canister, carefully depress the plunger all the way in the canister, hold it there, and seal off the vacuum inlet on the canister with your finger. Now let go of the plunger. It should not move back out at all as long as you have the vacuum inlet plugged with your finger. If it moves out, it's leaking and you'll need to replace it. If it does not appear to be leaking, reconnect the vacuum line and start the car. Check to see that the vacuum pull-off is, in fact, completely pulling the choke off. You can tell by looking at the choke plate over the primary venturi on the carb. It should be very nearly completely open. If it is not, your choke linkage will need to be adjusted.

Hope this helps. Good luck.
 

Pegasys

Well-known member
Joined
May 17, 2002
Messages
48
Location
Toronto, Canada
Corvette
1973 Red Coupe
Thanks guys...I tried the easy spray carb cleaner routine today. We'll see how it starts tomorrow. A lot of black "guck" did get cleaned from the carb...

If not successful, will try Stringray 72s idea...Mike
 

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