Dual carb blower linkage problems.
 

Guys, I have a pair of B&M 250s with Holley double pumpers. We opted to use an Enderle linkage kit with the fat roller bearing bell crank that bolts to the blower. I cannot get the linkage to work right and I’m pulling my hair out at this point.

I’ve followed a pretty good article from On All Cylinders and the carbs themselves are setup okay (meaning that there appears to be no binding though it is hard to move the secondaries… I think lubricating the accelerator pump arms will help). As soon as the cable goes on it.!it’s harder to move. I feel like I got the starboard side to be acceptable,!but when I duplicated the same on the port side, I thought I might actually break something.

The cables move freely so they’re fine.

The configuration as it sits has the control cable pulling from the top (10 o’clock position on the bell crank) with the linkage rod pulling down and toward the back of the engine (2 o’clock position on the bell crank). Similar to this picture though the picture shows the bell crank at 11 and 2-ish.

https://cimg2.ibsrv.net/gimg/www.off...bbef02a16.jpeg

I need as much travel space as possible between the linkage rod and the cable rod otherwise they bind (with the 10 and 2 setup I’ve got about 1/8 inch before they touch, maybe a little less).

The setup in my 242 was similar but used a different bottom bracket. It was smooth and easy to move - this one sucks.

Hardin Marine sells what I’m using:

https://www.hardin-marine.com/p-980-precision-roller-bearing-dual-carburetor-linkage-kit-bmholley-250.aspx

Of course no instructions are available.

Any ideas?

Tom, can you see/feel where it's binding with someone moving the controls? Disconecting 1 carb, how does it feel.

As you know, it's spherical rod ends with multi-angular movements. Are any of the rods ends binding under load?

I found the instructions here:

https://static.summitracing.com/glob...9500531-01.pdf

They operate pretty smoothly until the secondaries are opened, then it’s tight. I think that’s because the pump arms need lube at least on the starboard side. Without the cables attached they seem to be acceptable. Maybe it’s a mechanical advantage thing.

Thanks!

Wish it had some pictures though. I’ll see I can find based on the instructions.