The Stovebolt Site Forums The Shop Area Engine Shop YF2100S carb problem

I am just about done with a major facelift on my '52 3100. It ended up with a 1959 235ci. motor out of a car. The rodchester carb that is on it now runs fine but leaks gas and I can't seem to correct that problem. So a while back, maybe 6-8 months, I got a Carter YF2100S carb and rebuilt it. Now that I am very close to actually driving this dinasour I don't want to burn it to the ground!!!! The Carter is sucking way too much air and I can't seem to find out why. I say this because I can put a rag over the carb throat and it will run ok. Not real tight just enough to block a bunch of air. Remove the rag and it dies. Any common mistakes that may come to mind when rebiulding a Carter that would cause this condition? I do have the correct "heat block" (or whatever u call the spacer between manifold and carb). Any suggestions would be appreciated.

Have you tried adjusting the mixture screw?

will get back to it on weekend. Tks for the suggestion. As I stated earlier it has been some time since I worked on it. I'm sure I did try the mixture screw but will dbl check on Sat. That would be the obvious besides the right "gaskets". It's definitely getting way too much air from somewhere.

will get back to it on weekend. Tks for the suggestion. As I stated earlier it has been some time since I worked on it. I'm sure I did try the mixture screw but will dbl check on Sat. That would be the obvious besides the right "gaskets". It's definitely getting way too much air from somewhere.

This is a completely normal condition until the engine comes up to operating temperature.

If the engine is at normal operating temperature, then check for a vacuum leak.

Jon.

Of coarse vacuum leak is the most likely cause but a low float level can cause it. The diaphram on those carbs are flimsy. It is easy to not get it on right. Make sure all the idle passages & air bleeds are open.

OK I reinstalled the carb after checking float and cleanliness. I messed with the mixture screw until it will almost idle on it's own. I have the same problem. I can get it to start and run only using choke AND a rag to block air flow. It will not idle on its own. It's sucking air from somewhere. Will die with revving up to higher RPM. After getting it to warm up I sprayed some starting fluid all around carb. No difference. Remember that the Rodchester carb runs fine so there are no issues around intake gaskets or vacuum leaks around carb base. It's gotta be in the carb or gaskets that mount the carb. since it runs fine with other carb. Here's a question that might be causing this. The heat block with the 2 small slots. Does it go on with the slots up or down? Also, the gasket that then goes between that block and the carb- Should it be covering both holes on bottom of carb or should holes in gasket allow passage of air/gas through these holes? Carb is getting plenty of gas.

I have a 2100s on my 52 235 and when I got the kit the base gasket was the wrong one. You have to cut out a slot in the gasket for both holes in the bottom of the carb base.One is for the pull down on the pump so it can pull the needle down into the main jet and that is the one that is blocked by the base gasket.I took my dremal tool with a cut off wheel and cut a slot in the gasket from the center hole out to the hole in the carb base.


Pete

The insulator plate on my truck is marked top

...pic...

You can see the slots are on top.

Note: it's a 216 manifold

That is the way my base gasket is slotted but the hole for the pull down did not line up with thoes slots or the ones in the insulator plate so I had to make my own so the vac would pull down the acc. pump and needle to the main jet.

In pic #76 of Dads pics you will see the hole on the right side for the main jet needle that needs to be cut out for the 2100s carb.


Pete

...click pic 76...

you had to modify the gasket only? What about the insulator plate?

I cut a grove in the plate also.I forgot I did that,I think that could be a sign of old age.



Pete

Thanks guys. Unfortunately I think I have both heat spacer and gasket on correctly. Meaning the holes are up on heat spacer and both holes on carb and gasket are not blocked. Thank u for your efforts in trying to find this problem. But that just confirms that so far "things" are set up right but I still have the problem. The carb is so simple inside that I can't seem to see anything that I may have missed or put together incorrectly when rebuilding. But obviously something is still not right. I'll look at it again on Sat. Any other suggestions or things that I might try or look at/for? I am running out of ideas, that's the frustrating part!!!

Are you certain all the parts in the Carter carburetor are for that carburetor? I am not that familiar with the Carter carbs, but, since the rochester works fine, it boils down to a lack of fuel, or a vacuum leak

10-4 on the vacuum leak. I just can't find it. I am almost certain it is internal, in the carb. Sprayed starter fluid all around exterior after forcing it to warm up and no difference in RPM. I'll keep asking questions and trying. Eventually I'll find out what it is!!!!! TKS

Hopefully CARBKING will pick up on this and give you an idea

carbking wrote early in the thread. He misunderstood something because he stated, that what I was saying ( will run holding rag over carb throat to restrict air flow) was completely normal. So yeah, hopefully he chimes in again. To sum things up- heat block and gasket appear installed correctly and no luck with vacuum leak test. Looking for suggestions on what to do next. I would say dbl check internals in carb to see if all is well. Of course that's my problem. This is the 1st Carter I have messed with so I don't really know what I am looking for. To me all looks as it should. Thank you.

The only thing I see wrong with the carb is the adjusting screw is bent. It screws in and out but u can tell it has a bend in it. It COULD be letting in too much air but that seems like a long shot. Suggestions anyone?

Be sure the throttle blade is not bent and is closing 100%. If someone has removed it once, it might not be centered in the bore. Also check that the blade is in right side up, the edges are angled to help seal the bore.

Joe

Im interested to know what the problem was, I too just rebuilt a Carter Y-F and it bogs down when I try to accelerate.

About a year ago I bought a YF 2100S off of Ebay, I rebuilt the carb and I took special attention to make sure every passage in the carb was clear and lo and behold I found one that was plugged solid,after cleaning the passage I test ran it on my 52 with 235 and it works perfectly. I would check EVERY passage with compressed air and a wire to make sure they are open. Dave

Yeah I may need to pull the thing and double check. I just tried to adjust idle screw and I couldnt tell it did anything. I screwed it all the way in with motor running and it didnt seem to change the way it ran. It was screwed out 3 turns when I started.

What homer52 said.

I recently rebuilt a Carter YF 2100S and it runs beautifully. Took me about 3 weeks to rebuild because it was so gummed up and stuck. I really studied on it, and there are a number of passages that meet internally around the idle screw. I had to slowly dig them out using a drill bit (not in a drill, with my fingers)

I would work at it, soak it, clean it blow it out and repeat until I was sure that all the passages everywhere were free. Sometimes you have to hold you finger over one to get it to blow out another as a passage might have three outlets.

Kurt

Worn throttle shaft allowing vacuum leak? Is there any play in it?