MTD Snow Blower die under load

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  #1  
Old 01-24-16, 02:44 PM
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MTD Snow Blower die under load

I have an MTD snowblower. When I start the snowblower, it dies when I put it under a load.

I have tried a number of different things, and it dos not seem to help.

1- I purchased a new carb... no luck.
2- I replaced the spark plug, and it starts better... but still no luck.

Basically, it will run all day (or until it runs out of gas) while under no load. I can walk around the entire yard with it until it runs out of gas. Once I put it under a load... dies.

Also, if I start it, and run it... it will run. When I turn it off and restart it... it is hard to restart it.

Snow Blower MTD 611 series , Engine HSSK50

Thank you
 
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  #2  
Old 01-24-16, 02:58 PM
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Does your carb have the mixture adjustment screw on the bottom of the float bowl? If so first set the idle mixture with the screw on the side of the carb - in until the engine falters, then out for smooth idle. Then, at full throttle, do the same for the float bowl mixture screw. Then turn the bowl screw out another quarter turn.
 
  #3  
Old 01-24-16, 02:59 PM
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While walking the blower around the yard under no load, go up an incline at less than full throttle and see if the governor increases the RPM of the engine, If not, get a diagram and verify the governor linkage is correct. If the RPM increases, do a compression check on the engine and compare it to the engine specs. You may have a leaking valve or valves. Good luck.
 
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Old 01-24-16, 03:00 PM
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What kind of coil does it have? Does the spark have a blue tint? It should!
 
  #5  
Old 01-24-16, 03:23 PM
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there is no mixture adjustment screw on the bottom of the float bowl. Thanks
 
  #6  
Old 01-24-16, 03:35 PM
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I used the same spark plug in the manual , A resistor spark Champion RJ-19LM. Thanks
 
  #7  
Old 01-24-16, 03:57 PM
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What adjustments did you make to the carb either new or old? Did you clean the old carb before buying another one?
 
  #8  
Old 01-24-16, 03:58 PM
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I don't think it's getting enough gas; check the vent in the Gas Cap and check for debris partially blocking the outlet of the Gas Tank.

Why'd you replace the Carburetor . . . . same issues ?
 
  #9  
Old 01-24-16, 04:14 PM
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Mine acts up that way at times. I have a craftsman..

Its a briggs motor.. It started bogging down and stalling out under load today during the big snow storm clean up.. Ran great all morning..

Then stalled out and bogged under load..

I did not fix anything and it just went away after a few restarts.. ( Runs fine idleing)

I attribute it to the governor not ramping up the engine speed.. Sticking governor? Snow got in there? IDK but I would check that IMO..

Like I said it fixed itself.. Its been happening for me once in a while during big snowstorms with high snow. ( Snow is higher then front chute..

Just my 2 cents..

While walking the blower around the yard under no load, go up an incline at less than full throttle and see if the governor increases the RPM of the engine, If not, get a diagram and verify the governor linkage is correct.
 
  #10  
Old 01-24-16, 04:24 PM
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I replaced the carb in the summer for same issues so I did not have chance to try it under load. Today with the big snow storm we got I could not use it! I did not do any adjustment to the carb, the new carb has no mixture adjustment screw on the bottom. there is no debris blocking the outlet of the gas tank, but I did not pay attention to the gas cap vent. I will do so in the morning. Thanks
 
  #11  
Old 01-24-16, 07:59 PM
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I myself do not have any experience with SNOW except for playing in it when I was a kid in 1974 here in South Louisiana. It got deep in the ditches. LOL

Seems to me that your governor is not moving accordingly. You might want to check that the linkages are moving and throwing in the right directions. Spray some silicone spray on there and see if it does right.
 
  #12  
Old 01-24-16, 09:09 PM
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I have an older White Snow Boss (MTD) with a Tecumseh that does the same thing. I was able to get by with it for the last few years by adding some upper cylinder lube to the fuel and richening the fuel mixture, but it would still die sometimes under load. Starts right up afterward so I got used to it. I guessed that it had a sticking valve or something because sometimes it would backfire as it was stalling. That's why I tried the upper cylinder fluid.

But .. today as I was moving it out of the garage I noticed a faint blue sparking coming from under the metal carb/control cover, behind the slot for the throttle control. Mine has a plastic on/off key that grounds the coil, but also has a grounding switch on the throttle when moved a bit below idle position. I pushed on the tin cover below the throttle and the engine sputtered & backfired a bit, so I just pulled the cover outward a bit until I felt it bend slightly & so far it seems to have mostly cured the problem. I'm guessing that something isn't right about the throttle ground switch or mounting but haven't pulled the cover off yet to check.
 
  #13  
Old 01-25-16, 08:07 AM
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I checked the fuel cap this morning and it seems to be in great condition, vent is working, no cracks !. The linkage is moving right. as soon as it throwing very very little snow it dies . I do not know what else should I do!
 
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Old 01-25-16, 08:09 AM
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I mentioned the coil yesterday. No one commented.
 
  #15  
Old 01-25-16, 08:23 AM
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Did you clean the old carb first or just buy one of the Chinese jobs for $11.95

It really sounds like you're not providing the engine with enough fuel. That could be anywhere in the fuel system - tank- lines - carb.

First try putting the choke on about 1/2 and see if that makes any difference.

If it doesn't pull off the fuel line that connects to the carburetor and let a quart of fuel run out in a clear jar. See if there is any water in the fuel and make sure you have a good steady stream of fuel available to the carburetor.

Let us know what you find out.
 
  #16  
Old 01-25-16, 02:01 PM
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I put the chock half way did not make any different . i pulled the fuel line connected to the carb and drained all the fuel, was no water and no blockage . i put fresh fuel , it give me hard time starting , still does the same. i shut it off , could not restarted right away, with very few snow lost power and die again!
 
  #17  
Old 01-25-16, 02:55 PM
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Do you know where the coil is located? It's connected to the spark plug wire. There is also a small wire that goes from the coil to either a kill switch or a connection to the throttle so you can put the throttle in the stop position and the engine will die.

You need to follow the spark plug wire from the plug to the coil and look for any leakage of current. Then disconnect the kill wire from the switch or throttle and follow it back to the coil to see if there is somewhere the current is jumping to ground.
 
  #18  
Old 01-25-16, 03:03 PM
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When I worked for Lincoln Mercury, in the 70s, a fellow mechanic said, "A carburetor is the first thing that people blame & the last thing to go wrong". I mentioned that here once before & was told that it was wrong. However, that's one of the reasons that I mentioned it in my first response. The second reason was that it makes sense that a load would affect it.
 
  #19  
Old 01-25-16, 03:05 PM
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Sounds like it might be time to dig a bit deeper. Depending on your ability, valve clearances, head removal.....
Page 24 of this manual shows the breakdown for the engine you listed in the OP.
 
  #20  
Old 01-25-16, 04:14 PM
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n the 70s, a fellow mechanic said, "A carburetor is the first thing that people blame & the last thing to go wrong"
I'd say in that period that is true, at least a lot of the time. I worked on primarily big block Chevy, Fords, and 440 Chrysler engines and over the course of several years I only saw one Rochester Quad and one Thermoquad where something in the carb had broken. I put a lot of kits in while cleaning, but rarely was the carburetor the problem.

Now with short shelf life fuel and applications where the machine sits idle for months, the first place I would look is the fuel system for either varnish or deterioration of lines and neoprene components.
 
  #21  
Old 01-25-16, 04:40 PM
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Things certainly could have changed. I can't argue that.
 
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