The Stovebolt Site Forums The Shop Area Engine Shop Carter YF Carb - sticking

I rebuilt my Carter YF carb from my 1958 Panel 261 engine. It was a mess before, but is running much better despite the accelerator pump linkage being fabricated from a nail! But shortly after reinstalling it it has started to stick at a high idle when releasing the throttle. This caused it to fail Air Care (Smog Check.) A quick kick of the pedal releases it and it idles properly - it is the slow release of the pedal that causes the problem. I removed the throttle linkage and it does it the same thing (releasing by hand at the carb) so I know it it is not the linkage but the carb itself. The throttle shaft is not sticking although it does seem a bit loose. I think it has to do with the choke or pump linkage even though they seem to be adjusted properly. Has anyone had this issue?

Has anyone used different carburetors on their straight six? I kind of like the idea of an electric choke - just because I think it is more environmentally friendly. Personally, I prefer the efficiency of a side draft carb too because the air is regulated more efficiently but that seems a bit radical.

Could you use a Rochester BC carb on your engine? The B is manual choke, BC is automatic choke.
Smog check on a 1958 vehicle............??

John

Yes John, here in BC we have smog check for all older vehicles. It will be eliminated in December 2014. It is annoying for those of us who own classic cars. I will take a look at the Rochester BC. Thanks.

That can be caused by a butterfly that is slightly out of alignment. When you rebuilt the carb did you take the butterfly out of the throttle shaft? It isn't hard to get it just a little off.

I didn't take it off the first time, but I did this afternoon. I checked the throttle shaft for wear - a bit loose but not too bad. The pump lever/rod was not adjusted properly. When the throttle was closed the pump was not fully seated. I am wondering if that was holding the throttle plate open. I bent the nail that is being used as the rod and the action seems pretty good. I had to run an errand, but it is all back together now so I will give it a try in afew minutes. Thanks for the help Jim and John.

it was better for a few minutes, but it went back to sticking after warming up. The pump seems to work better though. I could try to hook up spring to the carb itself. I believe most carbs want to close on their own - this one seems to sit open when it is on the bench. The schematic from the carb kit doesn't show any throttle shaft spring.

if it's a manual choke, it'll be the choke links sticking, more than the carb itself ... the Roch B manual choke has a spring on the choke, #21 shown here, and the YF may have similar, maybe this one - but also see original documentation here, one pic [page 2 of "Carter Carburetor Corporation Form 3526, December 1949: Service Procedure, YF Downdraft Carbureter"] shows a coil type spring [#21] as part of the choke .... the YF is a good carb, you should be able to get it working right, and do replace the nail with the correct part
edit: found a pic showing a spring on the choke linkage

Bill

Thanks so much Bill - this is awesome. Looking through those pages I see that there are a number of washers missing (but they may be in the kit.) The choke spring is also missing, As you suggest, that is probably the source of the problem. I was suspicious because the idle adjustment screw (not the mixture screw) lands on a strange part of the fast idle/choke linkage. One would think it would land on the large flat area even though that is mainly for stopping on the carb body. But where the screw lands now looks freshly burred, so something weird has happened recently. Hopefully, I can find some carb parts tomorrow at the big swap meet in Abbotsford.

This documentation is much better that the kit instructions. Once again, I owe you big time!

Unbelievable luck to report! At the swap meet today I found a guy who had a freshly rebuilt Rochester. It would have fit but I walked around looking for an exact match. I came back and asked him if he had any more. We looked on his trailer and what did we find but a newly rebuilt Carter YF! For $30!!!
So in a few minutes I will install it and hope that one more annoyance is off the list.

The base was a different size, but I was able to use the linkage I was missing and the float pivot that was also a nail. I noticed the fast idle lever from the choke linkage had a burr that may have been causing the problem. I filed it flat and replaced the screw with one from the new carb. I also made sure to adjust the throttle plate to prevent any binding. So far it seems to be working although I couldn't take it for a decent test drive.

Thanks all!

I put an extra spring on the linkage and was able to get it through AirCare. Thanks again to everyone who offered help! It still is binding ever so slightly - especially when warm. I am thinking the problem may be where the spring is located. Mine is in the linkage at the pivot point. Is this where it should be? I am thinking that the full spring tension is not being transferred properly to the throttle shaft. Thanks again to all helpful Bolters!