I rebuilt carbs & didn't ask questions first

[Biffmini]

I have two identical H50 carbs I rebuilt a few years ago when I was just getting into the hobby
I recently installed one on one of identical H50's 67038A 33480
Problem I'm having engine wont idle but will run with throttle wide open... So I'm assuming Stuck ball Ck. ( no rattle! ) Both carbs
I have a manual & I'm not seeing any info on how to address the issue.
I'm hoping to save these original carbs as both engines are showing very light use & are in great original condition.
Any help would be greatly appreciated
I sure am hoping to save these 1973 twins

 

[Dr. Shop Teacher]

I'd start simple and try cleaning the idle jet first. Make sure the needle is not bent or damaged. Clean every orifice you can get a thin wire or needle into (use carb or brake cleaner). Then, if still no luck, go to your local shop and order a "real" Tecumseh rebuild kit. Follow the instructions in the manual and rebuild as directed. I usually start 5/8 turn on the idle jet and 1 1/2 turns on the main jet and tweak from there.

 

[Biffmini]

I'd start simple and try cleaning the idle jet first. Make sure the needle is not bent or damaged. Clean every orifice you can get a thin wire or needle into (use carb or brake cleaner). Then, if still no luck, go to your local shop and order a "real" Tecumseh rebuild kit. Follow the instructions in the manual and rebuild as directed. I usually start 5/8 turn on the idle jet and 1 1/2 turns on the main jet and tweak from there.

Thanks I did put a rebuild kit complete as per manual, the carbs have been cleaned every orifice clean as a bean.
But I did a little research on the rebuild i got from OldMiniBikes part# 631839 With a little more research on my carb # 430, I came up with service # 631702
then looked up Tecumseh rebuild kit for that, shows I need repair 31840 So it looks like I purchased the wrong kit. That is if my research is correct.
But Still no rattle???

 

[markus]

Drill baby drill I posted this info up awhile back gives you some ideas to get in the passage......

Here you go https://oldminibikes.com/forum/inde...t-find-help-needed.160675/page-2#post-1185772

And to go along with that info that I posted about the idle circuit in that thread, I had actually drilled out the plug on one since that posting and pulled the rod out. (not a great pic was trying to focus on the corrosion buildup on the rod, this one did not rattle and barely passed any air or liquid through the passage):

gotta figure an easy and reliable way to plug the hole back up still... don't want to risk any type of adhesive plugging the very tiny drilled inlet in the main port though, a lot of times the plug actually looks like a tiny freeze plug, but I have not really tried to do any searching as of yet...I was thinking of pressing in a piece of solid AL rod or something. Hopefully I can find a solution for that and get some more of these saved that I cant get freed up and degunked.

Page 10 of the Tecumseh service manual shows a cutaway drawing showing the rod, and the warning that I gave in the info I posted in the above linked thread about needle installation as well. I have to say after actually drilling one out and pulling the rod, I believe that the rod is actually nothing more than reducing the passage in size and not actually serving any other purpose, hence why its important to make sure you hear it rattle, If not it plugged or restricted even more than it already is. I always thought it opened a closed a passage as you came on and off the throttle but that does not seem to be correct. And a "fun fact", the rod is actually the same diameter/material as the float pin, only not as long. It is about 3/32" dia where the carb passage is 1/8".

Double Bonus Fun Fact, in the pic below the assembly in the upper left is the high speed needle for a Dellorto UA19 (black widow carb). the Tecumseh float pin is also the pefect size for pin (makes the T) so you can make adjustments.....for some reason this carb assembly was missing it, it was an NOS out of box unit so maybe it was never installed or something, never the less I will be using a Float pin for it