The Stovebolt Site Forums The Shop Area Engine Shop 235, idle takes off, runs way to fast? :(

so i put a 216's rochester B, on top of a 235 BC throttle body, on to a 56 235 manifold. it seems like when I get it going, the idle jumps WAAAAAAAAYYYYY high , then the engine stalls.

I have not changed anything inside the 216 carb, I have a 235 carb, but i havent tryed it out cause i didnt have a air cleaner for it. do i need to change the power piston or metering jet? is it doing this because I hooked my vac advance to the tube on the bc? the bc throttle body didnt have a vac advance connection.

I screw in the idle mix all the way, backed out 1.5, and tryed to back out the idle speed. it will seem starved if i go back to far, then if i screw it in a lil bit, the engine will run but the idle jumps SUPER high after about 2 seconds, then it either stalls out it i kill the ign cause it sound to fast

here is a clip of it. the first time its puttering for a bit. The 2nd time i start it at 45 secs, it takes off really high then stalls

www.youtube.com/watch?v=6DKNk5jNsQU

any ideas?

you can't make frankenstein carbs and expect them to work. This is probably why you are getting no responses, it is somewhat inconceivable to me why you would try and mix up pieces. What exactly do you have that vacuum advance hooked up to anyway. Disconnect that and plug the "tube" that you have it hooked to. I have forgotten to re-connect the advance for quite some time (several months? before I noticed) and noticed no difference in the way it ran. You would probably do well to get the right carburetor, they aren't horribly expensive. I don't believe you will ever get that conglomeration to run.

Give the 235 carb a shot

a truck air cleaner will fit
Of course youll have to PAINT it

Hi Drew, second what DADS50 says, however sounds like a classic vacuum leak. check where your 235 throttle body attaches to your carb body, carb body to manifold, manifold to the engine. This trick is dangerous: in a well vented area, take an unlit propane tourch and when it gets close to a vacuum leak, engine will speed up. Keep fire ext Handy just in case.

I though Ive heard a few ppl put 216 and 235 carbs together..
wrenchbender rat said
"What about useing the top of the 216 carb on the 235 carb. Change the main jet & power valve spring. Then you will have your manual choke."

I hooked my vac advance on the tube that goes from the throttle body up to the choke on the bc.

I think if it was a manifold leak id be starving for fuel right? cause it would be drawing air.

I cant use propane, my idel is rev'ed up high.

can i put a 55 up 235 rochester b throttle body on my 216 b?

Id try to grind out the holes on the 216 so it will fit the 235 manifold, but when i tryed to remove the throttle shaft, the brass screw snapped off in the throttle shaft. can i drill them out and go bigger?

I have swapped 216 and 235 bases with no problems.
I am still not clear on why your base does not have a provision for a vacuum advance line. I have never seen a B model without one.
I think your high rev is due to a vacuum leak, this could be internally in the carb.
You may want to go back to the 216 base and elongate the holes.

Ok , I think I get it. So I put a 216 b on a 235 BC throttle body, not a b.

Plug the tube or cap it on the bc throttle body and put the vac advance on the mainfold and make sure the vac hole on the throttle body is not covered by the gasket you have. I had the same condition you are having till i checked it out .It would not idle right.I found a used model B from a friend and now it runs well.