# Tecumseh HSK840 won't start



## jpapanas (Jan 10, 2005)

I have an MTD 4.5HP/21" Snow Thrower with a Tecumseh HSK840 2-Cycle engine. Took it out of storage today and tried to start it with no luck. 

A new spark plug has been installed and I'm using a fresh batch of 32:1 fuel. It has the electric start kit and it turns the engine over ok but it seems to fire and run for only a second - but only when I've pressed the primer bulb before hand. If I don't prime it, the starter will turn the engine, but it won't fire at all.

I suspect I'll have to try cleaning and rebuilding the carburetor. Does anyone have a .pdf service manual that covers the Tecumseh HSK840 2-Cycle engine carburetor rebuilding?

Regards,
Jim


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## bugman (Aug 12, 2004)

yeah sounds like its clogged somewhere. thats what happens to engines that sit up. even oil mix gas goes bad. some have presevatives to keep it fresh but most don't. the ones that don't you can use stabilizer then the oil mix. but yeah it does sound like a blockage. try using carb cleaner first. take the filter off and spray a little in it and turn it over. that might get it out.. oh and make sure the bolts that hold on the carb are tight and it seals good due it will not start from just them being loose.


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## jpapanas (Jan 10, 2005)

I checked the bolts that hold the carb on and they are tight.

I followed the proper storage procedure at the end of last season - drained the fuel and let the engine run until the engine dies to empty the carburetor - before storing the snow thrower in the basement. 

I've owned the snow thrower since December 2000 and this is the first season that it has failed to start...

How does the primer bulb work? Does fuel bypass the carburetor when you press the primer bulb?

Regards,
Jim


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## roperdude91 (Nov 10, 2004)

it forces fuel into the throat of the carb then when you turn it over, it has a slightly richer mix to help get the motor going


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## bugman (Aug 12, 2004)

if your in a hurry try some carb cleaner then starting fluid to get it going for right now. oh and draining the gas lets the seals and all dry out faster. you probablly have dried out seals and a 2 cycle has to have seals that are well sealing to start correctly or even at all.


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## jpapanas (Jan 10, 2005)

Success! 

I removed the carburetor from the engine and removed the fuel bowl and sprayed everything with carburetor cleaner (Carb Medic by Gunk - methanol free). I did not disassemble the carb any further because I didn't have a rebuild kit and it seemed pretty clean anyway... I reinstalled the fuel bowl and remounted the carburetor onto the engine using the original gaskets and fuel bowl O-ring for now.

To my surprise, it started and ran on the first pull! I didn't even have to use the electric start. But, after a few minutes it went into this cycle of almost dying and then revving up again, almost dying and revving up again,... 

I shut it down and waited a few minutes. I started it again on the first pull and this time it seemed to run well for quite a while. In fact, I was able to finish removing the snow from half of a double driveway before it started acting up again.

What is the Tecumseh part number for the rebuild kit for this carburetor? The only numbers on it are hard to make out because they are not stamped very well, but I think they are either 1446FOJ or 1446EOJ or 1446HOJ. The fuel bowl has the number 30 stamped into it.

Here's a few pictures of the carburetor:
Top
Bottom
Apart

Regards,
Jim


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## bugman (Aug 12, 2004)

yeah seems like it had a spot of fuel in their and just gummed it a little. when it ran then surged that was the engine burning off the cleaner and then trying to get clean fuel in. but afterwards it got it and went well. if its old and shows signs of broken or cracked seals they need replacing because they need to be sealed but sounds to me that its sealed right.


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## abilyk (Feb 4, 2005)

That's the same carb that I have on mine. Jpapanas, does the spring on the throttle plate shaft close the throttle plate by default when the carb is not on the engine?

Thanks,
Al


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## jpapanas (Jan 10, 2005)

abilyk,



> does the spring on the throttle plate shaft close the throttle plate by default when the carb is not on the engine


No. When you remove the carb from the engine that spring, that connects the governor shaft to the throttle on the carb, is disconnected and the throttle plate is free to rotate. There are no additional springs on the carb that hold it closed.

Why do you ask?

Regards,
Jim


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