Gas carb stumble

[1Blacksheep]

Carb has a Bad stumble just above 3800 , Willy gas. Any Idears ? thanks

[1Blacksheep]

How often should power valves be replaced ?

[Eamsnewbie]

Having same issues, foam was breaking down and getting
Carb.

[bob75]

check your excellerator pump arms and see if they are out of adjustment.

[LM14]

Is it as you pick up the throttle? Is it something new? Usually a power valve will mess up idle and make it sloppy. Hold it at WOT (please, with the motor shut off) and see if you still have .015 gap between the pump lever and cam driven arm on the accelerator pump. If it's something new, may be rebuild time. If it's always done it, pump squirters.

SPark

[1Blacksheep]

Idle is sloppy and sounds like it drops a cylinder when cold while idling till it warms a little.Both Acc pumps squirt great. This condition happens when you raise the RPM slow and easy not getting in the pumps. Happens on restarts from time to time. Think I got idle and Mid circuits screwed up from setting Idle with front 2 barrels. Just read that is bad LOL. The original carb that was tuned to this engine had 4.5 PowerValves in it (Quick Fuel) .This carb has 6.5s (Willy)both 750s.

[LM14]

Try a set of new 35 power valves and lowering the float level just a touch after you get that little trickle/see in the sight glass. Dropping your float level will make the idle settings sharper and stop that spillover when idling. The 35 power valve seems to work well for us with bigger cams. usually end up in the 35 to 45 area so I always carry 35's and seems to be almost a universal answer.

The sloppy idle is too much fuel being pulled in and the miss as you gradually accelerate is the power valve not applying additional fuel to the transition circuit, the time between idle and squirter.

Good lcuk,
SPark

[1Blacksheep]

Try a set of new 35 power valves and lowering the float level just a touch after you get that little trickle/see in the sight glass. Dropping your float level will make the idle settings sharper and stop that spillover when idling. The 35 power valve seems to work well for us with bigger cams. usually end up in the 35 to 45 area so I always carry 35's and seems to be almost a universal answer.

The sloppy idle is too much fuel being pulled in and the miss as you gradually accelerate is the power valve not applying additional fuel to the transition circuit, the time between idle and squirter.

Good lcuk,
SPark

Thanks 14, went with 4.5s 1st and it cleaned up and sounds crisp again.