Hey all,
When i go to start the 70 455 i have to literly pump the gas pedal 20 times before it starts? After the frist warm up it's fine. Accelerator pump in carb maybe?

 

After it sits for how long? Pop your breather off, look down into the carb and see if it sprays 2 solid streams of fuel when you pump it with the engine cold. Also make sure your choke is set correctly after 1 full pump.

 

When it's cold or a few hrs, yes did all that the stream starts and then stops after not in even quarter throttle. choke works good as it can with th way it's starting. 90 % sure it's the accelerator pump just wanting to see what other guys thought

 

QJets are famous for draining the fuel bowl via leaky well plugs under the main jets' passages.

Pull it off and throw a kit at it, new accel pump, chk for leaky wells or just epoxy em anyhow.

 

True, thanks

 

X 2, but also recheck the choke. Actually, the accelerator pump's purpose is not for starting the car. It is for enriching the mixture for smoother acceleration. If your choke is not working properly, the accelerator pump can enrichen the mixture and help it start, but the problem with starting is a drained fuel bowl from leaking and a choke not functioning correctly. The choke is what is supposed to richen the mixture when starting a cold engine, not the accelerator pump.

 

Yeah but if there is no Gas squirting in the carb it isn't going to start no matter where the choke is set. I did a test and put some gas down the carb to prove my theory and it starts right up when i add gas manually.
Thanks

 

I'll put my money on the accelerator pump too. You need to have a priming shot.

 

After thinking about it , it could very well be the fuel emptying out of the bottom of the carb makes sense. If it was the Accelerator pump why dosn't it do it when warm or have a dead spot???

 

Because when it's warm the rubber seal that's in there is much more pliable, however I would not rule out the bowl emptying either, that's easy to check by removing the top of carb and check for fuel after it sits.

 

If you warm it up to temperature and drive it for a while. Does it flood when you try to start it after it sits 10-15 minutes? If so it is leaky at bottom of carb.

 

Have you changed the fuel filter recently by chance?

"Stock replacement Rochester paper fuel filter element is located in carburetors fuel inlet housing. Built in check valve prevents fuel from draining back out of carburetor when engine is turned off. Note:
Check valve filters do offer more restriction to high RPM fuel flow than non-check valve filters. For performance applications we recommend Q2253 (No Check Valve Filter)"