Rebuilt Carb and now stuck in high idle

Dmax74

New User
Hey Guys. Dmax here. I'm new to this forum as a member but have been browsing it for some time now. I have a 1952 TO-20 that I just did a complete overhaul on the carb. I bought the comprehensive rebuild kit from this site. My problem is that it seems to be stuck in high idle. I set the idle adjustment screw to 7/8ths open and the main adjustment to 1-1/4 open. My timing was good before I rebuilt the carb, but they only way to get it to idle down was to either adjust the carb or turn themain adjustment in. I did re-verify that my TDC was correct and my points are correct. I tried adjusting the idle mixture but it had zero affect. My idle screw is all of the way out. Could this be a govenor issue? Or could it be a problem with the new components that I installed? I did replace the throttle plate and throttle arm. Some background on it. This summer my son forgot to turn off the shutoff valve and the fuel overflowed into my oil pan due to a faulty needle valve and float. I figured it was as good a time as any to rebuild it while also replacing the valve cover gasket and oil pan gasket which were leaking. I do have the factory service manual as well as the owners operating manual. Thanks for the assistance.
Don
 
I?m with rm on this. If everything else seems to be right there may be enough air passing over the throttle plate making it idle high. Perhaps it
went in upside down and then it would look closed but really isn?t

Let us know how it is going
 
I will give that a try and let you know what I find out. Besides just taking it out and rotating it how would I know by looking at it if it
was installed wrong? There is a marking stamped on it. I belive it is the number 20. When I installed it I was following the shop manual
which shows the throttle plate with a ^ as a indicator mark for orientaion. In my mind I was thinking that that was what the stamped 20 was.
I will try to get it taken apart again today, but that will be determined by how many honey-do's the wife is having me do today.
Thanks for the help guys.

Don
 
Back the idle adjust screw out until it cannot touch the throttle. Then loosen the screws on the throttle plate and move the throttle until it can close off the carburetor completely. Retighten the throttle plate screws and check again that it closes tight. Now adjust the idle screw until the throttle plate is just barely open. Reinstall the carburetor and start the engine, moving the throttle enough to keep the engine running, then make adjustment to the idle adjust screw until it idles where you want.
 
'IF' you installed all the new kit pieces correctly.. a lot of what you have going on... may not be wrong. A low idle on some of these engines is 800 rpm or more... it willl never idle like a Allis. The needles are adjusted to -wherever- they seem to work the best, 1&1/2 on some 2 on others, etc. Same with the timing, can't go by the book on something this old and - we won't say worn- but- we'll say 'broken in'? I have someone move the throttle up and down while i sit in front and just carefully turn the distributor to that one sweet spot where it will idle good, yet have the guts to open up and work well at full bore. You can't take the bugs out in a minute, take your time
 
RM, good advise.

All I would add, with the carb reinstalled, set the throttle lever to idle, be sure the throttle stop screw is seated against the stop. If not, the governor link will need to be adjusted slightly longer until it positively closes the throttle.

Also, the idle mixture screw will only have effect when the engine is at slow idle, down around 400-500 RPM. Turning the idle mix screw in richens the mix, out leans it.
 
Thanks Fellas!

Update... I took the carb off and low and behold the throttle plate was indeed installed "Incorrectly". I fixed that issue and also
discoverd that I had installed the choke plate incorrectly as well. That's what I get for trying to put it together on Xmas day while
watching a movie with the wife sitting next to me. Was going to start it , but wouldn't you know it ole Mr. Murphey showed up and my 3 month
old battery from Wally World was shot. Went and exchanged it for a new one, but will install it in the morning. I'm pretty she's gonna run
fine now. Again guys thank you for the help. It is much appreciated. Everyone have a Happy New Years and be safe.

Thanks,
Don
 
Great news and congrats on a successful rebuild. Sometimes it takes a couple of times to do it right. I?ve done my share of learning that way.
 

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