The Stovebolt Site Forums The Shop Area Engine Shop 235 won't idle right

Got the 235 I swapped into the '41 pick-up running and it won't idle down without dying. I checked the timing with a timing light and it seems to be okay. I'm thinking a vacuum leak at the carb or manifold-to-head connection (even though I have new gaskets).

The manifold and carb are off of a 216 so I could get the correct exhaust outlet and horn mount for a 1941 pick-up. I still have the 235 manifold and carb, and am wondering if I would be better off using them. I'm thinking about having a horn mount welded to the top of the intake manifold like the 216 and modifying the exhaust manifold so the outlet points in the right direction (straight down).

I'm basically trying to decide which would be the best way to go long term. Something tells me the Rochester carburetor is a way better carb than the Carter W1. I guess it should be because for one thing it's 15 years newer!

I haven'tbeen able to idle below about 1000 for as long as can remember....

vegiguy,

What year 235?

Did you try the carburetor idle-rpm adjustment fter a good tune-up:
- newly set points and plugs
- valve lash adjustment on a completely warmed-up engine
- timing to maximum vacuum
- setting carburetor idle mixture to maximum vacuum


I set my 1954/55 trucks' idle speeds at 450-500rpm as specified in the manuals (I do this even with dual carburetors).

My 1954 235 with Hydra-Matic transmission calls for 400-450rpm. After a tuneup, I used that range.

I do not know if I could have brought them down to the 400rpm 1941 specification.

A lot of people prefer the Carters over the Rochesters. I use original-specification Rochesters in my 54 trucks (yes, they "weep"), but I had a Carter on my 1948 Panel (back in the 60s - it worked fine).

It's a 1956 engine with hydraulic lifters. What kind of vacuum - manifold vacuum like using the port for the wiper motor to attach the vacuum tester to?

That's where I take the reading.

I would guess that a standard equipment engine that is well-tuned should be able to run at a recommended idle speed?

How many miles/years on the carburetor (since last rebuild)?

0 miles. I rebuilt the carb. a year ago as part of the total restoration I'm doing to the truck. Now I'm trying to get it going so it runs properly.

My 235 can idle as low as 300rpm
...click...

I also use a 216 manifold with a carter 787s carb


the vacuum test suggested above is a good starting point.

I got it idling better: found the vacuum leak. Now it wants to boil over, even with a 160 degree thermostat. I'm getting hardly any water out of the rear drain so I'm wondering whether the block is so full of sediment it is clogging up the cooling passages. I have some cooling system flush in it right now to try to break some of that up.