Tecumseh Engine hard start in very cold temps???


Old 02-18-14, 05:11 PM
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Join Date: Feb 2014
Posts: 31
Tecumseh Engine hard start in very cold temps???

I have 1999 Generac generator Mdl PP5000T that is powered by a Tecumseh 10 HP HM-100 159436P engine (carb p/n 640129) and a 12 VDC electric start. It has served me well over the years as power outage backup here in the northeast. I have never really had any problems with it until this year. I live in upstate NY and this winter has been especially cold the coldest I've seen in a number of years in fact. I normally run it once a month just to keep things working, however this past winter I have had a hard time starting it in very cold weather, in fact the starter gasped it's last breath trying to start it. I have since ordered a replacement starter.

In also own a Yard Man snow thrower, which is also powered by a Tecumseh 10 HP HMSK 100 Snow King engine (carb p/n 632370A). The snow thrower has never given me a day’s trouble starting even on the coldest of days. On this particular engine however the carb has a priming bulb, aside from this the engines look almost identical at least to me.

I was wondering if the HMSK100 carb could be used on the HM-100 engine. It seems like the priming bulb on the Snow King engine is the key to starting in very cold weather, or am I being simplistic in my assumption? Any thoughts or suggestions regarding a solution to the hard start in cold weather condition would be appreciated.

Thanks to all.

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Old 02-18-14, 05:25 PM
Join Date: May 2006
Location: Iowa!!!!!
Posts: 3,728
The primer would make a big difference in cold weather.

You have to distinguish the different ways a primer works with different engines. On an all position carb like a chainsaw/weed wacker most of those simply draw fuel through the carb and return it to the tank. It doesn't pump fuel into the carb throat/intake of the engine. It essentially loads the carb with fuel so it's readily available for the engine to pull the fuel out when starting. Those you can pump twenty times or five times with about the same effect.

On a fixed position carb like you have a lot of those will pump fuel directly into the carb throat and essentially does what the choke circuit does - provide a rich mixture for starting. Those you have to use a little discretion on how many pumps you give it, since each one is sending raw gas into the carb throat.

You can do the same thing by manually feeding some gas or starting fluid directly into the carb throat. If the problem is only on occasion that may be cheaper than replacing the carburetor.
Old 02-20-14, 04:35 PM
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Join Date: Feb 2014
Posts: 31
The HMSK-100 instructions says to push the primer 2-3 times before attempting to start the engine. Since both engines appear to be very similar if not the same with the exception of the carb they use I don't see why the HMSK-100 carb wouldn't work on the HM-100.

BTW, I finally got around to replacing the starter today and got it to start by heating the intake and carb with a hair dryer. However once it started it ran really rough, not surging or hunting, just sputtering and stalling but not to the point where the engine died completely. The carb that came with the HM-100 is a non adjustable and from what I was hearing and seeing today looks like it would not be a bad idea to replace it anyway with the HMSK carb which gives me a little adjustment ability. A replacement carb on Ebay and Amazon ranges anywhere from $38.00 for an Oregon up to the $90's for an OEM.
Old 02-21-14, 07:09 AM
Join Date: Dec 2006
Location: Canada
Posts: 528
You could try and spray some quick start into the carb throat and if it starts up quickly you will have a little more confidence in your theory, since the quick start should be doing approximately what the primer bulb is doing.

If it doesn't start right up then you know the problem is something else. I don't think one motor working better with a different carb confirms that the other motor's carb design is inferior. I certainly wouldn't want to spend the money on a new carburetor with only that evidence.

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