Stromberg 97 Accelerator Pump Rod length

[BRENT in 10-uh-C]

I have a customer who had a pair of 97s rebuilt by a well-known supplier for his 4 cylinder Model-A. When we finally installed them and started the engine, the engine will not idle down unless the rods are disconnected from the pump arm. The idle adjustment screws are both backed-off with an air gap. I cannot determine how to adjust it to have it idle down any further. Is there different lengths on these rods? Is there something I need to do or check??

TIA!!

[Terry,OH]

97 rod is 3.83" and the 48 rod is 3.61"

[Bored&Stroked]

Hmmmm . . . can't imagine why the accel pumps are causing it to not idle down . . . unless the rods are somehow holding the throttle plates open. Possibly the wrong length rods? I've never installed Stromberg 48 rods on 97's . . . but that might be the issue.

I would check and see if the throttle plate idle stop-screw is being pulled off of the stop when then the accel pumps are installed. If so, it almost has to be the wrong combination of carb bases and accel pump rods.

Do your carbs have TWO places to install the accel pump rods - one for winter and one closer to the rotational axis?

[Planojc]

Check with Max Musgrove 435-322-0102 in Salt Lake City. He is the 97 expert

[BRENT in 10-uh-C]

Originally Posted by Bored&Stroked

Hmmmm . . . can't imagine why the accel pumps are causing it to not idle down . . . unless the rods are somehow holding the throttle plates open. Possibly the wrong length rods? I've never installed Stromberg 48 rods on 97's . . . but that might be the issue.

I would check and see if the throttle plate idle stop-screw is being pulled off of the stop when then the accel pumps are installed. If so, it almost has to be the wrong combination of carb bases and accel pump rods.

Do your carbs have TWO places to install the accel pump rods - one for winter and one closer to the rotational axis?

Yes, the rods won't let the throttle shaft rotate enough to close the butterflies. When the rods are disconnected from the pump arms, the idle speed is tool slow of RPMs, -so it is the rods that are the issue.

And yes, there is a Summer & Winter ball setting to change that however they are on the same plane so it holds the butterflies in the same position on either ball.

Thanks everyone.

[nickthebandit]

Sponsored Links (Register now to hide all advertisements)

It appears to be that you have Stromberg 48 throttle rods installed.

[BRENT in 10-uh-C]

Originally Posted by nickthebandit

It appears to be that you have Stromberg 48 throttle rods installed.

I agree. Unfortunately this package came from an 'expert' rebuilder who went thru them, so the owner & I were hoping for a little better, but it is what it is, -and Speedway has a package on the way with the correct ones and a few other goodies.

Thank you for everyone that assisted with this!!

[Terry,OH]

Stromberg also sells their own parts on their web site. With the longer rods and the idle RPM screws out you will have to screw them in to increase RPM.

[Bored&Stroked]

You can buy almost all official Stromberg parts at Summit Racing - good solid parts vendor.