Abby’s Guide > Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) > Discussions > Tecumsh simply shuts off under a heavy load... lazy snowblower syndrome!

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grump

Joined: Jan 14, 2008
Points: 58

Tecumsh simply shuts off under a heavy load... lazy snowblower syndrome!
Original Message Feb 23, 2014 6:13 pm

Old Ariens with a HSK70 engine (original was H70), starts right up and throws fine with the throttle wide open.... until it gets to work hard then it quickly just dies.

I release the belt tension, can start it right up again, and ease the belt into position while it clears it's load. Then it's business as usual until the next big load is encountered and it dies.

What could be going on? It's always been easy to start by hand and there's Stabil in the gas.

My assumption is that it needs to run richer, but since it starts so readily hesitate to change the needle setting.

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mkd55

Location: wisconsin
Joined: Dec 16, 2005
Points: 155

Re: Tecumsh simply shuts off under a heavy load... lazy snowblower syndrome!
Reply #2 Feb 24, 2014 8:35 am

that's my guess too! the engine runs fine under light load and stalls out under heavy load. if you have good compression, fresh fuel, and good spark either a fuel starve issue or the governor isn't working properly. fuel starve could be jets, float level, needle and seat,or air leaks.

niper99

Location: London Ont
Joined: Dec 2, 2007
Points: 354

Re: Tecumsh simply shuts off under a heavy load... lazy snowblower syndrome!
Reply #3 Feb 24, 2014 12:13 pm

Is there any backfiring or muffling sound when it dies under load??.. My guess is the exhaust valve clearance is not correct and needs to be checked... is ur carb adjustable?.. the governor could be out of adjustment but its unlikely... valve clearance on valves should be between .004-.012..

jrtrebor

Location: Michigan - 3 hours north of Chicago on the lake
Joined: Feb 10, 2010
Points: 539

Re: Tecumsh simply shuts off under a heavy load... lazy snowblower syndrome!
Reply #4 Feb 25, 2014 12:00 pm

First off, if your carb. has an adjustable needle on the bottom of the float bowl.
Adjusting it won't effect how it starts.
The needle doesn't effect the idle circuit.
It is possible that you need to open up the needle a little.
It could be starving for gas under a heavy load.
It could also be a partially clogged main jet.
Most, if not all problems with blowers not running correctly are carb related.
Having said that, you can stall any engine if you put to much of a load on it.
I've got a 13hp Honda engine on my blower. And I could stall it, if I try moving
30" of snow at to fast a forward speed.
Not saying that, that is the problem. But just a consideration.

grump

Joined: Jan 14, 2008
Points: 58

Tecumsh simply shuts off under a heavy load... lazy snowblower syndrome!
Reply #5 Feb 25, 2014 1:40 pm

That may be all it needs, then. Great!

Thinking about some of the comments and how it behaves, I'm using it at full throttle and not truly overloading it but am expecting a lot from it. Like everyone else, we've had a lot of snow.

At full throttle it dies under heavy load instantly. It used to slow down and every bang bang bang of the engine firing could be heard and it recovered, but it didn't stall.

I can readily remove and spray the passages for both needles, what changes should be make to either's setting?

Tough call for inexperienced me as I can't readily replicate a load to see how it acts, and if we're lucky won't know if it's really fixed until next year!

Thanks.

jrtrebor

Location: Michigan - 3 hours north of Chicago on the lake
Joined: Feb 10, 2010
Points: 539

Re: Tecumsh simply shuts off under a heavy load... lazy snowblower syndrome!
Reply #6 Feb 25, 2014 3:04 pm

grump wrote:

At full throttle it dies under heavy load instantly. It used to slow down and every bang bang bang of the engine firing could be heard and it recovered, but it didn't stall.

I can readily remove and spray the passages for both needles, what changes should be make to either's setting?

It simply sound like you've got a dirty carb.
The fact that it used to perform better than it is now.
Sounds like you've got a dirty fuel system.
A fuel filter should pick up stuff coming out of the tank.
But it won't filter out everything.
You can build up debris in the fuel bowl itself.
Small bits of varnish, small amounts of water. Tiny, tiny bits of rust scale if you have a steel tank. .
It only takes a any extremely small particle to cause problems in a carb.
If you haven't messed with the carb yet.
I would simply try opening up the needle on the bottom.
An 1/8 to a 1/4 of a turn (clockwise) and see if that makes any difference.
Just spraying, usually won't fix things. You have to remove the main jet and
run a small wire into all of the small passages.
This link will show you some photos of the small passages.

This message was modified Feb 25, 2014 by jrtrebor

RedOctobyr

Location: Lowell area, MA
Joined: Nov 5, 2011
Points: 282

Re: Tecumsh simply shuts off under a heavy load... lazy snowblower syndrome!
Reply #7 Feb 25, 2014 3:24 pm

jrtrebor wrote:

If you haven't messed with the carb yet.
I would simply try opening up the needle on the bottom.
An 1/8 to a 1/4 of a turn (clockwise) and see if that makes any difference.

RIT333

Joined: Jan 3, 2008
Points: 33

Re: Tecumsh simply shuts off under a heavy load... lazy snowblower syndrome!
Reply #8 Feb 25, 2014 4:14 pm

RedOctobyr wrote:

You're the expert, not me :) But if viewed from below the bowl (so you could see the head of the screw for the needle), wouldn't you typically turn it counter-clockwise to open the needle, and allow more fuel to flow?

That is what I was going to say. The screws control the fuel flow, so, turning it "out" (CCW) will allow more fuel to enter.

jrtrebor

Location: Michigan - 3 hours north of Chicago on the lake
Joined: Feb 10, 2010
Points: 539

Re: Tecumsh simply shuts off under a heavy load... lazy snowblower syndrome!
Reply #9 Feb 25, 2014 5:01 pm

You're both correct.
I probably should have been clearer about that
I assumed that that carb was still on the engine.
So looking down at the carb. and reaching underneath the bowl.
You'd be turning it CW to increase the flow.

mkd55

Location: wisconsin
Joined: Dec 16, 2005
Points: 155

Re: Tecumsh simply shuts off under a heavy load... lazy snowblower syndrome!
Reply #10 Feb 26, 2014 10:40 am

turning the high speed screw counter clockwise or out as if you were trying to remove it will increase the fuel mixture.

grump

Joined: Jan 14, 2008
Points: 58

Re: Tecumsh simply shuts off under a heavy load... lazy snowblower syndrome!
Reply #11 Feb 26, 2014 7:05 pm

I'll check the fuel bolt for crud in the passageways and set the adjusting screw a tad richer.

Be great if that's all it takes and thanks for guiding me in the right direction.

Will post back how it goes after the next major storm, hopefully in a few years!

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