Old Tecumseh dies after running a minute or two

Here’s a procedure I taught my students to use, hope it helps.

Needle and seat replacement.

Remove the carb, and then remove the float bowl. Check the float bowl jet (which is the bowl screw) and make sure the jets both horizontal and vertical are clean and open. Tip the carb upside down and remove the float pin and float with needle attached. Look in the float needle passage and you should see the red float seat at the bottom of the passage. This is where a #5 crotchet hook would come in handy as you need to remove this seat. If you have no hook, but compressed air, you can blow through the fuel inlet and try to pop the seat out. Put your thumb over the passage to prevent the seat from flying who knows where. No air or hook try bending a stiff paper clip to dig the seat out.

I would either give the carb a good 24 hour soaking or have it ultrasonically cleaned at this time.

With the seat out clean the passage way with carb cleaner. Now you must find a drill bit slightly smaller than the passage way, to be used to press in the new seat. Apply a very, very small amount of a very light lube to the new seat. 3-1 oil or lighter, to help seat it better. Carefully insert the new seat in the passage way with the rings on the seat down toward the carb body. Slowly and carefully force the seat down with the back end of the drill bit. Once it is seated, check to see that it did not flip and the rings are up. Next check to make sure that the float does not have any liquid in it. If it does, replace. If everything looks correct, attach the new needle to the float and install with the float pin centered. It everything is correct, the float should seat level to the carb body, when looking at it upside down. If everything looks good reattach the float bowl, making sure that both the bowl gasket and the nut gasket seal properly. Reinstall on the engine and test unit. Remember to have patience and take your time. Good luck, but I don't think you'll need it.

PS: On the side of some Tecumseh carbs you will find a plastic cover. Under this cover will be an idle jet. Remove it and check to see that the jet is open both horizontally and vertically. You should be able to push the old float needle wire through the vertical opening.
 
Rivets, thanks for the detailed instructions. Just what I need. Mine doesn’t have the plastic cover. This appears to be a really simple carb with almost no adjustments.
 
Handle the Tecumseh carb carefully. Good replacements are hard to find and kinda pricy.
The older ones were fully adjustable jets. The later ones were the lean emissions type and the 10 hp Tecumseh engine on the gen's would surge and hunt quite often when first start cold on a gen or during cold weather which is not a good thing because the voltage goes up/down as the engine hunts and surges. Tecumseh really got some bad raps from the later emission type carbs causing surging and hunting from factory when new. Rivets mentions the fixed idle jet that is removeable and critical to smooth engine operation. I've opened these Al Gore fixed jets up for Generator engines to get smooth operation.
After replacing or cleaning carb needle and seats I confirm that the seat and needle is sealing good by applying about 5-7 psi with the float type carb's turned upside down. Unseat and seat it few times to confirm good seal and opening. Wet the needle and seat also. I use a blood pressure bulb or a mityvac that does vac and pressure..

If you do not have, download a free Tecumseh 3-11HP L-head Service manual.

Also a very user friendly ignition tester that allows viewing of the ign spark WHILE THE ENGINE IS RUNNING is a Oregon 42-087 In Line Spark Tester for about $15. Just connect it in series with the spark plug and start the engine.
It has a viewing window so as to watch spark while the engine is running.

Do not trust they ign testers that use a light, they will lie to you.
 
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Do not trust they ign testers that use a light, they will lie to you.
So true. The Christmas light types will not tell the whole story. Might have spark at low revs then vacate at mid and high revs. Taryl made a video on this exact thing. Open gap types are the best tools for the job.
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Handle the Tecumseh carb carefully. Good replacements are hard to find and kinda pricy.
The older ones were fully adjustable jets. The later ones were the lean emissions type and the 10 hp Tecumseh engine on the gen's would surge and hunt quite often when first start cold on a gen or during cold weather which is not a good thing because the voltage goes up/down as the engine hunts and surges. Tecumseh really got some bad raps from the later emission type carbs causing surging and hunting from factory when new. Rivets mentions the fixed idle jet that is removeable and critical to smooth engine operation. I've opened these Al Gore fixed jets up for Generator engines to get smooth operation.
After replacing or cleaning carb needle and seats I confirm that the seat and needle is sealing good by applying about 5-7 psi with the float type carb's turned upside down. Unseat and seat it few times to confirm good seal and opening. Wet the needle and seat also. I use a blood pressure bulb or a mityvac that does vac and pressure..

If you do not have, download a free Tecumseh 3-11HP L-head Service manual.

Also a very user friendly ignition tester that allows viewing of the ign spark WHILE THE ENGINE IS RUNNING is a Oregon 42-087 In Line Spark Tester for about $15. Just connect it in series with the spark plug and start the engine.
It has a viewing window so as to watch spark while the engine is running.

Do not trust they ign testers that use a light, they will lie to you.
Thanks to everyone who commented and gave me welcomed and helpful advice. I am pleased to say IT’S RUNNING! And, it’s running smoothly. I reattached the low oil sensor wire after installing a new needle seat and valve and ran it again. Turned off fuel and ran it until dry, then drained the tank and removed any residual fuel. It’s now back under my workbench until the next long power outage.

Thanks again!
 
Thanks to everyone who commented and gave me welcomed and helpful advice. I am pleased to say IT’S RUNNING! And, it’s running smoothly. I reattached the low oil sensor wire after installing a new needle seat and valve and ran it again. Turned off fuel and ran it until dry, then drained the tank and removed any residual fuel. It’s now back under my workbench until the next long power outage.

Thanks again!
If the tank is steel, I would coat it with oil. You can use 2 stroke or anything even used car oil. Plastic is another story. Or leave it full of Stabil treated fuel and never have to worry about it again. I run Stabil year round. Never an issue. Just the plain old school Stabil works for me. Buy small bottles and keep it moving for max freshness.
 
If the tank is steel, I would coat it with oil. You can use 2 stroke or anything even used car oil. Plastic is another story. Or leave it full of Stabil treated fuel and never have to worry about it again. I run Stabil year round. Never an issue. Just the plain old school Stabil works for me. Buy small bottles and keep it moving for max freshness.
Thanks for the tip. This tank is plastic. However, the tank on my new generator is steel.
 
Thanks to everyone who commented and gave me welcomed and helpful advice. I am pleased to say IT’S RUNNING! And, it’s running smoothly. I reattached the low oil sensor wire after installing a new needle seat and valve and ran it again. Turned off fuel and ran it until dry, then drained the tank and removed any residual fuel. It’s now back under my workbench until the next long power outage.

Thanks again!
Great news! Now pull it out once every couple of months and run it for 15 minutes. That way you know it is ready for the next long power outage.
 
FWIW...

I have an old Craftsman 10HP generator.
Changed the oil a couple years ago and it wouldn't start afterwards. I never use ethanol gas, fuel tank is plastic so no rust, etc etc

It also has an oil level sensor switch. The sensor ohm'd out OK. Sensor connects to a little diode/relay box, which in turn has a lead to the three wire on/off toggle switch.
Disconnected that wire from the on/off switch and it fired right up.
Been running without it ever since...not worried about it bc I check the oil before firing it up anyway.

Maybe one day I'll replace the diode/relay. Maybe not!
 
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