carb question
Thread Starter
Racer
Joined: Jul 2009
Posts: 350
Likes: 7
From: springstead wi
carb question
i have a 350 that i worked on years ago . but was never happy with the carb . its a r8 4010-1 the engine is bored over 30 decked 40 has a 350/350 kit with dart 65cc heads torker intake and crane roller rockers its also balanced . when i did a compression test years ago it averaged around 220 .in about 15 years ago that i built the engine it has about 3000 miles on it . but if you jump on it it seems like it runs out of gas . has electric fuel pump and is set at max around 5.5lbs .i havent played with it in years so theres probably more that ive done to it that i dont remember .
Burning Brakes
Joined: Jan 2003
Posts: 755
Likes: 32
From: Roswell Georgia
Bog Or Loss Of Power?
Are you bogging down under acceleration or just losing power as you accelerate? If you're bogging down, check the accelerator pump shot to make sure it's working. (The pump should tip in fairly quickly as you open the throttle.) Also check the electric fuel pump to make sure you still have at least 5.5 psi at the carb's fuel inlet all the time.
If you losing power as you accelerate, make sure your accelerator pump shot isn't running out of gas after the initial tip in. Check the fuel pump pressure as outlined above, and then check your initial (crank) timing as well as your timing advance as you open the throttle. (Chevys have a tendency to retard their timing if the distributor clamp loosens up with time.)
If the problem isn't the carb or timing, check your cam's timing. (You might have jumped a tooth or two on the cam sprocket under heavy acceleration if the timing chain was loose.)
Hope this helps!
If you losing power as you accelerate, make sure your accelerator pump shot isn't running out of gas after the initial tip in. Check the fuel pump pressure as outlined above, and then check your initial (crank) timing as well as your timing advance as you open the throttle. (Chevys have a tendency to retard their timing if the distributor clamp loosens up with time.)
If the problem isn't the carb or timing, check your cam's timing. (You might have jumped a tooth or two on the cam sprocket under heavy acceleration if the timing chain was loose.)
Hope this helps!
Last edited by mr.beachcomber; Jul 15, 2009 at 08:48 AM.
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
I'd be just about 100% certain that this is a tuning issue, and most likely a timing advance issue.
Use the timing sticky in the C3 Tech section to get your timing curve right, then circle back with tuning the carb
Use the timing sticky in the C3 Tech section to get your timing curve right, then circle back with tuning the carb
