Carb question

#1
Hey guys I have a Tecumseh that only runs with the choke on. I pulled the carb and cleaned it really good but it hasn't changed. I tried running it that way but it loads up and dies. What am I doing wrong? Is there a trick to this that I need to know?
 

chrisr

Active Member
#2
The main jet on these cabs is the bolt that holds the float bowl on and these holes get plugged and you can use a small paper clip or pipe cleaner for welding tips to clean them out. They sometimes don't look restricted, but actually are.

If your float bowl bolt has the adjustable screw, turning it counter clockwise will richen for wide open throttle and the screw below the idle screw, is your idle mixture screw that when turned counter clockwise will richen your idle and off idle.

Hope that helps.

https://www.allotment-garden.org/rotavator-manuals/Techumseh-L-Head-Engines-Manual.pdf
 
#4
Tore it apart again. Cleaned it again. I had a rebuild kit so I put a new main jet and needle in and still the same thing. I start it with the choke on and it runs away. As soon as I take the choke off it dies. I have been trying to adjust but it is almost impossible with it running so fast and with the choke on. Here are some pics. I can't tell what size engine it is. It is in a Ruppster and I would have to take the entire body off to really look at it.

DSC01262.JPG DSC01263.JPG DSC01264.JPG

I have another carb but I don't know if it will work Part Number 640152A

DSC01266.JPG DSC01268.JPG DSC01270.JPG
 
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#5
That's it! I have pulled this thing off 10 times, cleaned everything, adjusted everything and it still only runs with the choke on. I am about to roast weenies over the fire that used to be a Ruppster!
 
#6
As part of your multiple carb cleanings, did you ever pull the Welch plugs and clean behind them? That is kind of the last resort if you have done everything else. We have only had to do that on a couple of Tec engines (out of many) after we have done everything else. Also, HOW are you cleaning the carb? What are you using? Years ago we switched to a small ultrasonic cleaner from HF. We were able to get carbs operating that we were unsuccessful with "conventional" methods (carb sprays and dips).
Michael
 
#7
As part of your multiple carb cleanings, did you ever pull the Welch plugs and clean behind them? That is kind of the last resort if you have done everything else. We have only had to do that on a couple of Tec engines (out of many) after we have done everything else. Also, HOW are you cleaning the carb? What are you using? Years ago we switched to a small ultrasonic cleaner from HF. We were able to get carbs operating that we were unsuccessful with "conventional" methods (carb sprays and dips).
Michael
Yes, I pulled the Welch plugs. I used carb cleaner first then soaked it in solvent, then chased all of the holes and passages with a wire and a tiny carb brush, then carb cleaner again and then an air gun through everything. This thing is like new inside. Darned if I can figure out what the problem is.
 

CLH

Active Member
#10
Check the float level. It can change after messing with the needle seat. Speaking of which, did you make sure to install the floats needle seat with the groove down?
 
#11
Check the float level. It can change after messing with the needle seat. Speaking of which, did you make sure to install the floats needle seat with the groove down?
Yes, I rechecked the float level and made sure the seat was put in correctly. The only think I can think of is there is some blockage somewhere that I can't see. I have been wanting to buy one of the ultrasonic cleaners from HF for a while. I think it's time to do it.
 
#12
I have been wanting to buy one of the ultrasonic cleaners from HF for a while. I think it's time to do it.
One of the very best investments we ever made. Ours is going on 6 years now and has cleaned dozens of carbs- still going strong. Wait for a sale and/or a 20% coupon and they are very affordable.
Michael
 
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