Old Tecumseh dies after running a minute or two

Thanks for the responses and all the great advice! I found the engine tag when I removed the cover and have attached it. I removed the carb for the 3rd time and gave it another good going over. It appears that the needle seat is white rubber (?) which was somewhat deteriorated. I’m thinking that it had just enough space to fill the bowl but may have become stopped up when more gas was needed. Just a guess. When I tried removing it with dental-like tools, it came out in crumbles.

Can I buy a replacement needle seat and needle or will I have to buy a complete carb?
 

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Tdj2591 said:
Thanks for the responses and all the great advice! I found the engine tag when I removed the cover and have attached it. I removed the carb for the 3rd time and gave it another good going over. It appears that the needle seat is white rubber (?) which was somewhat deteriorated. I’m thinking that it had just enough space to fill the bowl but may have become stopped up when more gas was needed. Just a guess. When I tried removing it with dental-like tools, it came out in crumbles.

Can I buy a replacement needle seat and needle or will I have to buy a complete carb?
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Needle and seat are available online. You had a white seat that was original and very old. The new ones are Viton and orange in color. There are several videos online of how to install the seat properly. The seat has to be pressed into place by hand carefully with the correct side toward the needle.
 
Tdj2591 said:
Coleman Powermate 5000 Maxa ER Plus generator with a 10 hp Tecumseh bought new in 2005, Used 3 times, running only non-ethanol fuel, about 10 years apart. Turned off gas and ran engine until it died each time, then drained tank. Always stored inside and never exposed to weather. During recent ice storm my son borrowed it. I replaced the spark plug and added an in-line fuel filter and it started and ran smoothly for at least 24 hours. It died about 4am due to low oil shut down by oil sensor. He added oil and restarted it, but it ran rough and died after a minute or two. He may have added a little too much oil. He had to have power and bought a new generator when the stores opened and returned mine.

I removed and cleaned the carb, which appeared to be very clean. Needle and seat showed no wear or build up. No trash in the carb. Easily blew air thru fuel lines. Gas filter had plenty of fuel visible in it when I refueled it. Spark plug appeared okay and gap was correct. Changed oil, filled to correct level and changed air filter.

It started on first pull but ran rough even after turning off choke. Plugged in a 500 watt light and it smoothed out slightly, then died. Backfired when it shut down. Easily restarted but again died within a minute or two. It acts like it might be fuel starved. I verified that the fuel line was not collapsing, the fuel valve was completely open and not blocked and the filter had fuel in it.

The gas cap had an inner plastic disk that had deteriorated with lots of small to tiny pieces of plastic falling into the tank. The tank’s filter screen kept the plastic particles from the engine (unless smaller than the holes in the screen, and some were minute). I removed the tank, cleaned out all the debris and installed a new gas cap.

I’m not a mechanic. Any idea what might be causing this? Should I dismantle the carb and make sure that all passages are open? I didn’t change any carb screw settings.

Tecumseh HM80-100 (no serial number) L head
Coleman PM0525312, serial 94520848
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the Tecumseh tool part #670377 is used to insert the seat. One end has the hook and the other the insertion tool. Be careful that the seat does not roll over if you try to use something else to insert it. There is a generic one on Amazon for about $6. Originals are around $20. It is also used to check float height.


670377.jpg
 
A lot of times on a time related issue, fuel tank has trash in it. Some form of deficient fuel delivery to the carb. Pull the hose off AT the carb inlet. Make sure you have solid flow there.

Longshot, a no vent fuel tank cap.

Could be a weak ignition coil.
 
slomo said:
Probably because the engine is so packed down with dirt and oil, you can see it.
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Slomo, your comments were addressed in my original post. The tank had bits of deteriorated plastic fuel cap in it. The cap is a two-piece design. The inner “flap” had completely disintegrated and fallen into the tank. The tank was removed and thoroughly cleaned as was the mesh screen. The cap was replaced with a new cap.

The generator was only used 3 times in 21 years and was always stored under a workbench in my garage. Other than a little dust, it was virtually as clean as the day it was purchased. The engine was run dry and the tank was drained dry after each use. It started on the first pull and ran fine when brought out of storage and gassed up. The problem occurred only after my son ran it continuously for over 24 hours following an ice storm and the low oil sensor shut it down in the middle of the night. He ran fresh ethanol-free fuel that I provided.

I installed a new in-line filter before he used it. I blew out the lines and made sure fuel was flowing. The fuel lines looked new and were not collapsed or swollen. Fuel flowed freely thru the filter. The carb was removed and cleaned with all orifices cleared. There was no trash or varnish in the carb.

I’m ordering a carb float kit to replace the rubber needle seat which appeared somewhat deteriorated.

By the way, I take really good care of all my small engines, zero turns, large mowers and ATV and clean them after each use. Nothing I own is ever “so packed down with dirt and oil, you can see it.” My ATV is 19 years old and still looks and runs great.
 
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