1978 305 acceleration and high speed problem

[hazelheckler]

Hi ,, 1978 sea ray with 305 228 hp quadrajet carb.

Starts fine idles fine, accelerates ok if throttle pushed very slowly up to 3100 rpm. If i try to push it any more the engine starts to run rough and looses rpm, i have to reduce the throttle to about 1500 rpm before the engine smooths out and i can begin to accelerate again, but only to 3100 rpm, if i hold this speed engine runs fine, also fine at rpm's below this.

new gas, fuel line, fuel filter. Removed carb, dis assembled, cleaned, replaced gaskets accelerator pump, and needle and seat, installed a non warped airhorn.

If i try to accelerate quickly the engine gets really rough and won't accelerate.

Thanks

 

[spdracr39]

Re: 1978 305 acceleration and high speed problem

Sounds like a fuel filter or old gas. After checking those two things a rebuild and deep cleaning of the carb might be in order.

 

[hazelheckler]

Re: 1978 305 acceleration and high speed problem

new gas, fuel line, fuel filter. Removed carb, dis assembled, cleaned, replaced gaskets accelerator pump, and needle and seat, installed a non warped airhorn.

 

[Bondo]

Re: 1978 305 acceleration and high speed problem

Ayuh,.... Welcome Aboard,.... Is the fuel pump pumpin',..??

Is the Tank givin' up it's fuel,..??

 

[spdracr39]

Re: 1978 305 acceleration and high speed problem

Ayuh,.... Welcome Aboard,.... Is the fuel pump pumpin',..??

Is the Tank givin' up it's fuel,..??

I don't think that extra info was in there when I read this the first time but it was early and I hadn't finished my coffee yet:facepalm:

Check the fuel line vents to make sure they aren't plugged, the anti siphon valve to make sure the check ball isn't stuck, and the fuel pickup screen in the tank. If all that checks out it could be an ignition problem but it sure sounds like fuel.