Tecumseh HM100 part thottle issues

R

RegalX

Member
#1
#1
I have a fresh rebuilt Tecumseh HM100 and a new carburetor and I am having trouble getting it to run correct. The engine has a stock carb/linkage/governor. It starts and idles fine however once under load it bogs hard and sometimes dies.

Engine has an ARC rod, valves and seats have been ground, valve clearances set. Small amount of porting around the valves

Current carburetor settings: Idle mixture 1.5 turns out
Main jet 2.25 turns out

Any suggestions? Could it be governor related? I have tried to adjust the main jet out 1/8 turn at a time with the same results..
 
Last edited:
chrisr

chrisr

Active Member
#3
#3
Usually it seems like a bog under load may be to lean but have you tried turning in the jet 1/8 at a time to see how this does for the bog? Did you check for fuel flow into a can from the gas tank to insure it flows good and float level is level? Never mentioned the air filter, does it run any better under load without it? Good compression, spark and spark plug? Just covering the basics when all seems OK.
 
R

RegalX

Member
#4
#4
Still bogs and doesn't run right when I turn the main jet out. I'll check the fuel line tonight, if the tank is above the carburetor is there any need for a pulse pump? It doesn't currently have an air filter. I've put multiple new spark plugs in it. They all look pretty rich when I pull them, but not wet. I am currently running an Autolite Xtreme Start Iridium spark plug.

I think I am going to pull the carb tonight and make sure there isn't shit floating around in the float bowl. Also might check the lash on the valves and gap for the coil.
 
chrisr

chrisr

Active Member
#5
#5
With the tank above the engine there is no need for the pulse pump. You may just try the stock plug and gap and double check the float level is level when turned upside down. When the points wear the gap is reduced as well as this retards the timing so you may want to pop the flywheel, check the points to see if they are burned and the current gap and if the points are burned replace the points and condenser and set the points at .20. Unless someone has messed with the timing you should be good once the points are set again at .20. There are some pretty good posts on OldMiniBikes on how to set the timing on the Tecumseh that you may find helpful. Here is one of those posts.

http://www.oldminibikes.com/forum/t...-timing-tecumseh-engine.html?highlight=timing
 
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