# Tecumseh No Compression...



## moonstation2000 (Feb 15, 2014)

I added an homemade impeller kit to my old Noma 29" earlier in the week and it was fantastic until the engine blew today. Coincidence? The 9hp Tecumseh Snow King engine was working really hard with all the recent snow we're gotten in PA.

I have no comression at all, zero on the gauge. Gas comes out through the choke plate of the carb when I crank the engine. 

Does this mean my intake valve is stuck open? Gas comes in from the carb then back out again?

The rest of the machine works fine even though it's late 80's - early 90's vintage so about 25 years old. I'd like to keep it working as a new unit would make my wallet cry!!


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## Shryp (Jan 1, 2011)

Blew an engine usually means the connecting rod broke. If the piston is not going up and down there would be no vacuum to pull the fuel from the carb. Gas dripping from the choke plate usually means a probably with the float, needle or seat.

Check under the gas tank and electric starter and see if there is a crank or hole in the side of the engine block.


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## nt40lanman (Dec 31, 2012)

Yea, sounds like a valve if it blows gas out of the carb when you pull it over. Pull the head off to see the top of the valve, pull the rectangular cover behind the carb off to see the stem of the valve.


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## motorhead64 (Dec 15, 2013)

Pull your spark plug..shine a light down your plug hole..see what's happening. MH


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## moonstation2000 (Feb 15, 2014)

The piston moves up and down when I crank it and puffs of gas mist blow out from the carb.


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## motorhead64 (Dec 15, 2013)

Your intake valve is hanging up. You need to pull your carb and your valve cover, and check your valve lash. MH


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## moonstation2000 (Feb 15, 2014)

I went out and took a look today. The one valve was not moving at all when I cranked (looking in through the spark plug hole).

i took the top cover off (head, or just valve cover?). The inlet valve wasn't moving so I tried pushing on it and it went down. 

When I crank it comes back up and stays up. I did this a bunch of times and added some lube to the point where it would slide down easily. But every time I crank, it comes up and doesn't retract.

Am I right in assuming that there is some sort of retainer that should be holding the valve down that must have broken/fallen off and is not probably swimming in my oil?

How much of a pain in the ass as I looking at to fix this? Is it time for a repower or a new machine?

I already had to lap the valves due to low compression a few years ago and I never got full compression back.


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## nt40lanman (Dec 31, 2012)

Behind the carb there's a rectangular cover. In there is the other end of the valves, along with the springs and retainers. Should be pretty easy.


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## moonstation2000 (Feb 15, 2014)

Thanks for the answer!! I'll check that out tomorrow. Hopefully I can get that valve sorted out and get the machine working again tomorrow so I can get my sidewalks done.


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## Shryp (Jan 1, 2011)

Sounds like either the spring broke or the keeper came off. Here is a video showing how to remove and replace them. It can be done with a screwdriver and pliers, but the tool makes it easier. You can probably barrow something similar from an auto parts store. If you are replacing the parts you might want to replace both springs and keepers at the same time.


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## GustoGuy (Nov 19, 2012)

Shryp said:


> Sounds like either the spring broke or the keeper came off. Here is a video showing how to remove and replace them. It can be done with a screwdriver and pliers, but the tool makes it easier. You can probably barrow something similar from an auto parts store. If you are replacing the parts you might want to replace both springs and keepers at the same time.
> 
> HOW TO USE VALVE SPRING COMPRESSOR TOOL ON SMALL ENGINES FOR REMOVING VALVES - YouTube


Give it a try. What do you have to loose since it will not cost too much to fix. It is not that hard and the Spring compressor tool is usually only about $20 or so. I would get a new valve and remove the head and get some lapping compound and lap the valve to the seat. You will need to adjust the valve clearence too and grind off any excessive valve length to get it into specs. New springs and keepers are a good idea since the old springs are most likely no longer at the proper tension after so many years use. New valves, springs, keepers and a head gasket and the engine could be as good as new.


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## moonstation2000 (Feb 15, 2014)

Thanks for the help guys, I went out today and took a look, and the retainer under the spring is broken.

I guess I'll break out the plastic and order some new parts.


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## Shryp (Jan 1, 2011)

moonstation2000 said:


> Thanks for the help guys, I went out today and took a look, and the retainer under the spring is broken.
> 
> I guess I'll break out the plastic and order some new parts.


Are you positive it is broken and not just popped off?


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## db9938 (Nov 17, 2013)

Shryp said:


> Are you positive it is broken and not just popped off?


I second that question. It is not common for a retainer to break. 

That said, I usually use an open ended wrench to compress it, and a flat bladed screw driver to push it on. I think its a 7/16 or half inch wrench.


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