5.7 bravo 3 runs good above 2000rpm

[Paulie2655]

Starts idles and rev up fine when it returns to idle it shuts down. Startup idles and doesnt run good till ovet 2000rpm

 

[Scott Danforth]

welcome aboard

we will need a bit more information since the Bravo has been around for almost 30 years and there have been 3 different styles of induction on the 5.7 as well as 4 major engine changes in that time

what year
what is your engine serial number
carb, TBI, or MPI?

 

[harringtondav]

welcome aboard


what year
what is your engine serial number
carb, TBI, or MPI?

Exactly. If it is carbed, I can help. Otherwise I'm out and other pros can help you fix it.

 

[Paulie2655]

2003 basic 2 barrel carb just see an electric choke to it for any wire to it dont know serial number when i order part for 1998 - 2001 5.7 evey is the same

 

[Paulie2655]

Where is the neutral safty switch located so i can jump out

 

[AShipShow]

A faulty neutral safety switch wont make the engine "run bad", it will make it not run at all. It grounds out the coil so you don't get spark.

 

[Scott Danforth]

based on posts 1 and 4 you have dirt in your carb. it may be coming from the fuel tank

time for a carb tear-down

pull your fuel filter, empty the contents of the filter into a clear plastic bag. make sure you only have clean, pure gasoline in the filter and not water/crud

 

[Paulie2655]

Mad props. I see your video on carb. I see it has a vacume plunger for idle circut. Maybe when i first start it has enough vacuum to pull it in but after i rev. It up and bactk to idle i dont have enough vacume to pull it backin

 

[AShipShow]

The vacuum plunger doesn't affect the idle/low rpm circuit. When the throttle plates are closed or very slightly open, the vacuum is very high and pulls the power valve piston fully closed so it doesn't touch the power valve and doesn't add any fuel. As the vacuum decreases as the throttle plates open, the power piston spring pushes it downward and pushes on the power valve, adding more fuel.

If you are only having problems at idle, it sounds like your idle circuit is slightly gunked up, and as Scott Danforth said, you need to pull the carb and clean/rebuild.

EDIT: re-read your post... You could have a sticking power piston, but result is the same... need to clean/rebuild.

 

[Paulie2655]

No it not really at idle my problem just above idle till 2000rpm above its good. If i give it two pumps and it will start and idle

 

[Paulie2655]

But when i go to 1200rpm it runs for a second and shuts down but when i go from idle to 3000 rpm its fine

 

[Scott Danforth]

still pointing to dirt in the carb

 

[harleyman1975]

Clean rebuild cab pay special attention to the accelerator pump circut.

 

[Bondo]

A faulty neutral safety switch wont make the engine "run bad", it will make it not run at all. It grounds out the coil so you don't get spark.

Ayuh,...... Welcome Aboard Paulie,..... Lotsa points to cover in this thread,.....

Plain, 'n simple, you've got a carb problem,..... Best advice is to do as Scott stated in post #7,.....
It'll fix yer carb, 'n determined whether you've got problems up-stream in yer fuel System,....
Step #1 is to pull the fuel filter, 'n examine it's Contents for anything but clean fresh gasoline,.....
A plan of action can be developed from there,....

Lastly, this ^^ quote is all wrong,..... MP is explainin' the operation of the Shift Switch,.........
Not the neutral safety switch,....

The neutral safety switch only breaks the voltage from the key, to the starter,.....
It has absolutely no bearin' on how the motor Runs,......
It only disables the Starter's Start circuit,.....

Not complainin', just pointin' out the typo for future reference,.....
As Mad Props obviously knows 'bout what he speaks,....

 

[AShipShow]

Oops.. good catch.. sometimes i need to slow down and actually think about what I'm typing

 

[Paulie2655]

Ok i check both fuel filters no dirt or water clean. Carb only had a little oxidation on bottom floor. Cleaned With lhigh pressure air and cleaner replaced power valve(looked sketchy) cleaned powervalve ports. Replaced seat needle and float. Didnt like the aftermarket accl.pump plunger so used old oem. And tested on ear muffs and all good.

 

[Paulie2655]

Next time i am just buying oem parts i just dont like like aftermarket parts all i newded was gasket power valve and needle and seat