Tecumseh snowblower engine surge

Hello, My Ariens 724 snowblower engine surges during warm-up. The engine surging subsides by adding partial choke. After warming completely, I can turn the choke off without any surging. The engine is a Tecumseh OHSK70. I cannot find carb adjustment info on this engine. Any suggestions would be greatly appreciated.

 

Sounds like a developing fuel restriction, most likely varnish build up, I would suggest putting some SeaFoam or Chevron Techron in the tank, a little stronger than recommended on the can, either product will desolve the varnish, you might get lucky and not have to clean the carb. Have a good one. Geo

 

Thanks Geogrubb for the feedback. Will try your recommendation. If I must eventually clean the carb, do you have any suggested links to perform that task. I have some experience with two cycle carb kits, no experience with four cycle.

 

The link below should provide the cleaning info you will need. Have a good one. Geo

Disassembly of Tecumseh Series 1 Carb 632107

 

Thanks again Geo. I finally found SeaFoam. Added to fresh gas as you recommended. The engine no longer surges. I think I avoided a carb rebuild. Thanks again for your response to my problem.

 

Success is a wonderful sound. Have a good one. Geo

 

Hello again Geo,
As a followup, I read the carb rebuild info from your suggested link 'Disassembly of Tecumseh Series 1 Carb 632107'. I checked the oil level and it was much too high suggesting possible inlet seat problems (gas intrusion). I am changing the oil and replacing the carb. I intend to inspect the original carb and rebuild if necessary as a backup. The article discusses a rubber inlet seat. Can you advise how to remove/replace the seat? Replacing the needle is straightforward. Also, the bowl nut on my carb does not include an adjustable needle. Other than idle speed adjustment, there are no other adjustment screws. Thanks