# tecumseh 2 cycle won't stay running



## abilyk (Feb 4, 2005)

Hi, I have a craftsman snowblower with a 2 cycle tecumseh engine (hsk600 I believe or very similar) that will not stay running for more than 10 seconds. It starts great but then dies. There are no adjustments on the carb and just cleaned it all out and got it to start. I know I still have to fine tune the tang on the float. It will run a little longer with the air intake almost closed right up (choked fully plus tape). The throttle is also controlled by the governor. There is a spring on the throttle shaft but seems to be there solely to reduce verticle vibration of the throttle shaft because there are no ends on the spring to use it to retract the throttle plate closed.
So I have multiple questions:
1. Is the throttle spring supposed to retract the throttle plate or should it be free?
2. There was no air filter on this unit when I found it on garbage day. Is a filter that important to maintain proper fuel to air ratio in these designs?

Thanks in advance for any input and expert advice.


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## bugman (Aug 12, 2004)

garbage day???, umm without the filter it would have sucked more crap up in there then a garbage truck could hold. most likely the carbs still crapped up. i would highly recommend a carb rebuild, a full one, new diaprahm which sounds like the main prob and full new seals etc. then get a filter to put on it. needs a filter definetly a filter filters out the crap in the air and the snow, really doesn't affect the ratio of fuel just filters and make sure the ratio is the right ratio little less ain't good, more then normal is better but smokes, and make sure all the engine seals are tight and i mean tight, 2 cycles are picky when it comes to seals. they need to seal perfect to run right. oh and since its a junker, make sure the plugs not gummed up and sparks real good to give you a better starting. oh and the spring should open and close the throttle plate. it should move freely. ie it should close and open on demand.


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## abilyk (Feb 4, 2005)

Hi Bugman, thanks for your reply. The unit is in pretty good shape. It looked as though the original owner tried to fix this thing himself and gave up because the carb was loose with only one nut on it and the needle and float were loose inside the bowl when I found it. Probably didn't bother putting the air filter back on since it was being thrown out. 
Anyway, the spark was the first thing I checked and is good. I did do a complete rebuild on the carb with a kit. As for the throttle, the original spring is there but the ends of the spring did not hook on anything (the spring ends did not protrude to hook on anything. Maybe broken.). Is this spring supposed to close the throttle plate when the engine is not running?


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## hankster (Jan 1, 1998)

Most of the inexpensive "paddle" type 2-cycle snowblowers (actually snowTHROWERS) do not have an air filter on them, just a little "scoop" pointing up to keep the junk off the ground from being sucked up. An air filter on this type of thrower would quickly be soaked with water and choke out the engine.

In most cases, the carb is gummed up. Pull the bowl off the bottom of the carb, remove the float and seat. Watch how it comes a part so you know how it goes back together and don't loose any of the small parts. Spray the carb well with carb cleaner (inside the seat where the needle come out of too) and then put it back together. While the carb is apart, make sure the fuel flow from the tank to the carb is OK.

The screw holding on the float bowl is an adjustment, turn it a 1/4 turn out and see if that helps.


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## bugman (Aug 12, 2004)

well the spring should hook to something, most likely broken might just hook to the carb and the throttle, the throttle should open and close by moving up the throttle control up and down and when running stay at what you have it at, the carb should be tight to the intake and seal good. both bolts are needed, not to much on those 2 cycle tecs, worked on a couple old ones but newer ones are well a little out of my knowing. if its a float model then try and make sure the screws are set at the right increments. if they aren't it'll flood the internals and choke itself off.


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## hankster (Jan 1, 1998)

These throwers don't have a throttle control... they always run full speed. Haven't worked on one since a year ago last fall but I believe the spring should hold the throttle butterfly closed.


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## bugman (Aug 12, 2004)

huh thats a new one to me, used to the ones with throttle control.


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## jpapanas (Jan 10, 2005)

abilyk,

This is what the governor to throttle linkage looks like on my float style carb on a fixed speed Tecumseh HSK840 as used on my MTD snow thrower:
Linkage 

The spring is referred to as a "backlash spring" and it doesn't really control the position of the throttle plate - the "governer link" does that. There is no other spring on the carb that keeps the throttle plate closed. There is no air filter on mine either.

I have found this site really useful in getting exploded diagrams - you can zoom in and click on part numbers to get descriptions. If you have an HSK600, you need to get the specific model that should be stamped on the engine itself, for example HSK600-1622P.
http://manddmower.com/parts.asp

Here is the Tecumseh service manual that covers an HSK600:
http://www.cpdonline.com/692508.pdf 

Hope this helps.

Regards,
Jim


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## hankster (Jan 1, 1998)

All the spring does is "dampening" more or less.


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## sketchydave (Dec 20, 2009)

Jim, if we ever cross paths I am buying you a beer. I came across this thread (now nearly 4 years old) and the service manual you posted saved my bacon. We have a big storm tomorrow and my snowblower was doing the exact same thing. The culprit was the small fuel passage in the annular groove of the retaining nut had gotten gummed up. I had been smart enough to drain the gas out of the tank, but not smart enough to empty the fuel lines and fuel bowl of the carburetor. So the gas aged and there was likely a little bit of water in it that corroded that itty bitty groove. Some carb cleaner and a little work with a needle and its all better. No way I would have gotten that without that manual. THANKS!!!!


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