bigger carb?

[263 build]

i built a farmall 263 last year to 291. running a 656 carb(i was told)now.runs way to fat down low runs great on top. but i cant get my rpms much over 2800.would another carb help these issues?also was thinking of experimenting with e85 witch i was told will require more fuel on the high side.i would be interested in another carb if someone has one or am i looking in the wrong area. thanks

 

[Anonymous-0]

You need to get a 715 combine carb, this will fix your rich condition on the idle side.

Here is whats going on,,,

A 656 carb is a twin port carb, which means it has only two ports to deliver fuel to the manifold, one is thru the metering stem, the other is thru a passage in the throttle body. When the main jet is too rich and too much fuel is going thru the circuit it will flood it on the idle side.

The 715 carb is what I call a triple port carb, which means it has 3 ports of delivery, which is all focused on the main load, but it gives you more fuel thru the ports and stem, and keeps the main jets smaller so it does not overflood the idle side. it has an extra passage that it baded off of throttle position, which brings the fuel in stages,, low amounts for low rpm operation, and alot of fuel when its wide open.

A huge difference in performance.

you need to see which venturi size you have,,, if its not a #35 you need to have a 35 for that setup, but your twin port 656 carb will have trouble feeding the 35 without having a little fight over idle quaility. The 715 throttle body is a quick fix to that. I am able to bore them out to a larger bore and make a real big carb, but with your current carb, it will still have the idle problems.

RPM,,, shave the weights down, get a single arm combine governor housing, and rebuild custom adjustable linkage that hooks up to the governor arm. With this setup, I was able to have a 400 rpm idle speed and a 3200 rpm peak all in one motion. The change was quite a bit,, revved up faster, it was smoother, it held rpm harder, I liked it. Hope this helps a bit. ChadS