Engine Surging Problem

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  #1  
Old 01-27-03, 11:06 AM
mcneilal
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Toro Snowblower Rpm Changes

THE ENGINE REV'S UP AND DOWN AFTER IT IS STARTED. BLOWS SNOW ALRIGHT. OLDER BLOWER BUT USED LITTLE. DID MY BEST TO CLEAN CARB. SLOW IDLE NOT WORKING VERY WELL.
WHAT ARE THE POSSIBLE REASONS FOR THE SPEED CHANGES?
ON THE CARB THERE ARE THREE SCREWS WITH SPRINGS. ONE ON TOP FOR IDLE SPEED. ONE IN THE MIDDLE (MIXTURE)? ONE UP THROUGH BOTTOM OF BOLT THAT HOLDS FLOAT CHAMBER ON(MIXTURE)?? IS ANYONE FAMILIAR WITH THESE?
ANY THOUGHTS ARE APPRICIATED.
 
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  #2  
Old 01-27-03, 04:45 PM
Joe_F
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Kill the caps, no need to shout.

I believe you have trash in the float bowl bolt. There are three tiny holes in there and if they are not spotless and clean, it will run rough/surge/spit/stall.

Clean them carefully and thoroughly with carb cleaner and a pin or nail.

You don't mention much about engine #s or equipment specs, so I assume we are talking about a Tecumseh engine of some sort.

(Most Toros use Tecumseh engines on their blowers)
 
  #3  
Old 01-27-03, 07:56 PM
cheese's Avatar
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Hello mcneilal!

I agree that you have fuel problems. I don't know what engine you have though. Assuming, like Joe, that you have a tecumseh engine, the tiny holes mentioned MUST be cleared and open. The 3 screws you mentioned are idle speed, low speed mixture, and high speed mixture. Before adjusting these, the carb needs to be completely clean, or you won't get the adjusments right.

Starting with the high speed adjustment screw (the one under the bowl)...run the engine at full speed. Turn the screw in until the engine begins to stall or run badly, then back it out 1 turn.

The low speed adjustment screw (on the side of the carb in the middle)...Turn it clockwise until it lightly bottoms out, then back it out 1 1/2 turns. Run the engine at idle and fine tune from there. 1/2 to 2 turns from closed is all it should need. If it is not in that range, you have carb problems.

Let us know how it goes!
 
  #4  
Old 01-31-03, 05:24 AM
mcneilal
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thankyou for your replies. sorry for caps, i have been informed.

i did not find an engine tag so i can not tell you which engine or year. it is a toro 824, model 38080. there is a number (hm80-155291m) near spark plug on the engine cover.

i have removed carb and cleaned with a carb cleaner spray. i have cleaned holes in bowl bolt and two more in center column of float area. it start easy now and i can adjust hi mixture but it still constantly changes rpm (hunts) and backfires. can not go to slow idle without stalling. i have turned low mixture but does not make any difference. i then cleaned carb again. same problems.

the snowblower was not used much but is around 10 years old. passed down from my father.

al
 
  #5  
Old 01-31-03, 01:31 PM
Joe_F
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Sounds like it needs a carburetor rebuild. You have an 8HP Tecumseh engine on this machine.
 
  #6  
Old 01-31-03, 11:33 PM
Tcumcman
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Engine Surging

McNeilal,

Joe and Cheese have already pretty well established the
problem with the engine is carb related. The engine surges
because it's not getting enough fuel. The governor and carb
are "fighting" one another, and when you try to run the engine
at idle and it cuts off, indicates the idle circuit is restricted or
even blocked. Sometimes this passageway is next to impossible
to get cleaned out, and might require a new carb. NEW carb
for an HM80 155291N is part #632334A and costs $75.32 if
you cannot rebuild it to work properly.

Tcumcman
 
  #7  
Old 02-12-03, 09:55 AM
mcneilal
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thanks to everyone. snowblower working. installed a carb kit. while installing kit i found three small holes behind a aluminum plug beside the low speed jet. two of these were plugged. shot of carb cleaner and a needle and all is fine. once again thankyou.
al
 
  #8  
Old 02-12-03, 05:35 PM
cheese's Avatar
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Posts: 16,575
Glad you got it going!
 
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