# Techumseh HSSK50 is hard to start and keep running



## bergs (Nov 26, 2013)

I'm working on a murray with a Techumseh HSSK50 which had been stored outside in the weather for years. I replaced the rusted out carb and it will run if i use the electric starter and hold it for about 20 seconds then it will run and sound good for about 5-10 seconds before it fades out and dies. I replaced the coil and spark plug as well and it still does the same thing. One time i got it to run for 5 minutes and i took it up and down the driveway. I shut it off and it would not start again without the electric starter and it would die again after a few seconds. I'm wondering if it could be the valves? I've never opened one of these up and I'm out of ideas. Any assistance is appreciated.


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## crazzywolfie (Jun 2, 2014)

before going too much farther have you checked/clean the fuel system. possibly replaced the main supply line. i know sometimes the fuel lines collapse or clog with age.


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## bergs (Nov 26, 2013)

crazzywolfie said:


> before going too much farther have you checked/clean the fuel system. possibly replaced the main supply line. i know sometimes the fuel lines collapse or clog with age.


Yea, the fuel line flows very well and is in good shape. I've popped it off the carb a couple of times and it will flow out nicely. I'm going to replace the primer line next but i doubt that will have much of an effect.


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## detdrbuzzard (Jan 20, 2012)

if it has points and a condenser you might want to check them


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## bergs (Nov 26, 2013)

detdrbuzzard said:


> if it has points and a condenser you might want to check them[/QUOTE
> 
> no points, it has the solid state coil. I believe it is from the early 2000's


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## classiccat (Mar 1, 2014)

low compression would cause a hard-start issue; Valve lash &/or head gasket are the usual culprits... less frequently it's the cylinder walls / piston rings.

Do you feel much resistance when you slowly pull it over?


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## tadawson (Jan 3, 2018)

The carb was replaced with what, exactly? Offshore parts can have QC issues . . . . might have gotten a bad or misaadjusted one . . . and not sure how the old one could 'rust out' considering that they are not steel or iron based . . . Did you consider cleaning the old one, or even open it and look? Might be an option, at least to test . . .


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## bergs (Nov 26, 2013)

classiccat said:


> low compression would cause a hard-start issue; Valve lash &/or head gasket are the usual culprits... less frequently it's the cylinder walls / piston rings.
> 
> Do you feel much resistance when you slowly pull it over?


The resistance feels about the same as any other similar sized snow blower, not unusually hard to pull.


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## Nhpyro (Jan 16, 2018)

Tecumseh motors are so temperamental, especially the carburetors..If rebuilding the carburetor wont work, best bet is to replace the carb with an OEM carb, but check the valves and cylinder first before you invest in the carburetor..


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## Dauntae (Nov 10, 2016)

Highly don't think the carb would be doing that, OEM carb will cost a fortune and the chinese carbs are pretty good, I have yet to get a bad one and I have used them a LOT. With the compression, These engines have a compression release for starting so until it fires and the rpm starts coming up they ALL have lower compression. Go to a auto zone or the likes they have tools they let you use and get a compression tester and use the electric start to test it to get the rpm high enough to stop the compression release. If it has low compression then that will tell you and odds are it is a valve or head gasket.


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## GoBlowSnow (Sep 4, 2015)

How many times are you priming it? 20 seconds on the electric starter is a bit too long. should be no longer than 5.


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## orangputeh (Nov 24, 2016)

i am wondering about compression and/or vacuum leaks also. if it runs and then stalls, would this mean a possible fuel delivery problem? if it ran for 5 minutes and then would not restart would this point to a possible flooding condition? do you smell gas? did you pull plug and was it wet?

one time i had a similar problem and found out when of the carb mounting nuts was loose but if you just put on a new carb did you change the gaskets or just use the old ones?

when it's running can you spray carb cleaner around gaskets and see if the rpms go up? 

i'm not a pro , just making suggestions on what i have learned here and done myself to find the problem.


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## tadawson (Jan 3, 2018)

For that matter, does this engine have the small intermediate intake manifold like the HSK's? If so, then the carb bolts to it, and then it to the engine, and simply putting a carb on does not ensure that all is secure - different bolts into the block . . .


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## bergs (Nov 26, 2013)

here is a video of it running. it will start if it has been sitting for a while then quickly die. then i cant start it with the pull cord. If i use the electric starter it will do the same kind of thing. The video is with the old carb cleaned out and put back on. It does this with the new carb too. It is not a carb issue. Makes no sense to me that it would start and then die and refuse to start again. the vid: 




Attached are pics of the new and old carb and the old coil that i changed. I'm going to pull the head off and check the valves next. I have a new head gasket


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## Dauntae (Nov 10, 2016)

That seems like a fuel delivery issue, Not the carb but it will run until the bowl is emptied then die, Won't restart right away until the bowl refills, Might have some gunk blocking the fuel line and it flows slower than needed, Fuel line is cheap and to swap it out on a Tecumseh use something to connect it to the old fuel line because it's a PITA to put in otherwise.


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## bergs (Nov 26, 2013)

Dauntae said:


> That seems like a fuel delivery issue, Not the carb but it will run until the bowl is emptied then die, Won't restart right away until the bowl refills, Might have some gunk blocking the fuel line and it flows slower than needed, Fuel line is cheap and to swap it out on a Tecumseh use something to connect it to the old fuel line because it's a PITA to put in otherwise.


when i take the fuel line off the gas runs out just fine. there is no blockage in the fuel line.


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## Grunt (Nov 11, 2013)

bergs said:


> The resistance feels about the same as any other similar sized snow blower, not unusually hard to pull.


I agree with classiccats theory on low compression caused by a valve not seating or leaking head gasket. As the engine starts, some wheezing can be heard coming from the carb or muffler?? Good compression SHOULD make it a little harder to pull than what is now happening.


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## tadawson (Jan 3, 2018)

Will it run any longer if you leave it at a lower throttle setting?


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## CarlB (Jan 2, 2011)

if your going to pull the carb off of it again remove the cover behind it and check the valve clearance. These engine are know for losing lash on the exhaust valve due to valve seat wear. I think the clearance should be .008 but not sure. There are many videos showing how to grind the valve stem on youtube.


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## bergs (Nov 26, 2013)

I pulled it apart. The exhaust valve is not sealing and actually both intake and exhaust have no clearance in the valvestems, i couldn't get any size feeler gauge in so i'm going to lap them and grind them.


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## tadawson (Jan 3, 2018)

The valves look good . . . gotta wonder if someone put new valves in and didn't set the clearance. Things really don't look too worn. Makes sense, though . . . . zero clearance, so any heat in the exhaust valve causes it to stay open. A bit of work, but a cheap fix!


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## bergs (Nov 26, 2013)

OK, it is all fixed and running great now. The valve job went great and it has a lot more compression now. I honestly think the real problem was fuel delivery. I checked again and i think the gas tank had some debris in it so i cleaned that. And I also think the new carb had a bad gasket on the jet which got frayed and was blocking the holes in the jet. Anyway, it is all good now:


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## bergs (Nov 26, 2013)

attached are some pics of the valve job and the crappy gasket that was frayed and blocking fuel flow of through the jet


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## orangputeh (Nov 24, 2016)

wondering what you found regarding the valve job? were the valves OK or burnt? was there a lot of carbon buildup? was the adjustments off? 

I'm new at this so would like to know what to look for if I come across the same problem.

excellent job , BTW, and great that you got it running right.


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## bergs (Nov 26, 2013)

orangputeh said:


> wondering what you found regarding the valve job? were the valves OK or burnt? was there a lot of carbon buildup? was the adjustments off?
> 
> I'm new at this so would like to know what to look for if I come across the same problem.
> 
> excellent job , BTW, and great that you got it running right.


There was a normal amount of carbon, a wire wheel made quick work of cleaning it up. The intake valve was sealing but the exhaust valve was not making a seal and the clearance was zero so I had to grind the valve stem to give it clearance. Both valves benefited from lapping them and giving them a nice new seal. It is not a hard job so don't be intimidated by it if you ever need to do it. The hardest part is getting the keepers back on the valves without the spring compressor tool. you just have to fiddle around with 2 screw drivers.


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## orangputeh (Nov 24, 2016)

bergs said:


> There was a normal amount of carbon, a wire wheel made quick work of cleaning it up. The intake valve was sealing but the exhaust valve was not making a seal and the clearance was zero so I had to grind the valve stem to give it clearance. Both valves benefited from lapping them and giving them a nice new seal. It is not a hard job so don't be intimidated by it if you ever need to do it. The hardest part is getting the keepers back on the valves without the spring compressor tool. you just have to fiddle around with 2 screw drivers.


Thank you. I've done it on an old 73 Toyota Celica head so this must be the same. Good job. Now you'll have a good running blower for years to come and your time investment has already paid off.


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## CarlB (Jan 2, 2011)

bergs said:


> There was a normal amount of carbon, a wire wheel made quick work of cleaning it up. The intake valve was sealing but the exhaust valve was not making a seal and the clearance was zero so I had to grind the valve stem to give it clearance. Both valves benefited from lapping them and giving them a nice new seal. It is not a hard job so don't be intimidated by it if you ever need to do it. The hardest part is getting the keepers back on the valves without the spring compressor tool. you just have to fiddle around with 2 screw drivers.


amen on the keepers


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## classiccat (Mar 1, 2014)

CarlB said:


> amen on the keepers





bergs said:


> The hardest part is getting the keepers back on the valves without the spring compressor tool. you just have to fiddle around with 2 screw drivers.


If/when you do get a spring compressor, I strongly recommend the c-clamp style. Soooo much easier! :icon-cheers:


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## Lindseywharris (Jul 16, 2018)

You probably solved this already. I just went thru this with 3 engines. Carbs get blamed and rightly so a lot of the time. But if there is no compression then there wont be much vacuum which is the thing needed for carbs to work. I did as Dauntae mentioned and used the cheap carbs and they worked when the compression is healthy. I tested maybe 4 engines with a compression gage and the pressures ranged from 60 hand pulling to 90 with starter. Those engines functioned well. One engine the exhaust valve wasn't closing and was an easy and cheap fix. Another engine when I removed the head had a grove in the cylinder like a keyway machined in. It was 1/8 inch deep and a good 1/2 inch wide and went to about 3/4 inch from the top. Pretty sure the pin got loose. But that stupid thing would run at high speed if you played it. But any way......Good luck


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## Motor City (Jan 6, 2014)

I would do a compression test, before I sink any money into it. If the rings are worn, it will act like your describing. People don't like taking care of their snow blowers and mowers. So they don't change the oil. And it trashes the engines eventually.


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