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1998 Toro 824 Powershift Snowblower - Engine Air Leak?


sod's Avatar
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11-09-09, 05:22 PM   #1  
1998 Toro 824 Powershift Snowblower - Engine Air Leak?

I have 1998 Toro Snowblower model 38540 with the 8 hp Tecumseh engine, model hmsk80-155386v. I was having a problem with the engine surging on any choke sitting but nearly full choke so I rebuilt the carburetor. The machine is running much better and the rpms do not drop down when I put a load on it.

One continuing concern is the muffler is still getting cherry hot almost immediately. It is warm here tonight, mid 50's, so that may be part of the problem. I do have the side cover off when running the blower.

A new thing I noticed tonight is that there is a noticeable air flow (leak?) at the front of the engine (the auger side) just to the side of the oil dip stick and directly below the spark plug position. Is this normal? If not what would case the leak and what is the fix.

Thanks for your help.

Ron


Last edited by sod; 11-09-09 at 05:44 PM.
 
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11-10-09, 06:55 AM   #2  
Your problem is the engine is running way too lean. This is the cause of the cherry red muffler and also the cause of the surging. From your description of the air leak, you have a blown head gasket. Replace the head gasket and your problem should be solved.

 
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11-10-09, 10:30 AM   #3  
One more question & Thanks

Indy,

I have already done a complete rebuild of the carburetor and still have the lean running condition as evidenced by the glowing muffler. The carb is the tecumseh 640052. i believe this is not adjustable. So how do you suggest I correct the lean running condition? Or are you saying the lean condition is related to the head gasket leak?

As to the head gasket, I was afarid this may be the problem. I search and found an online tecumseh manual for the 8- 14(?) engines. Is there any tips/pitfalls I should be aware of before tackling this job?

Thanks for the help.

Ron


Last edited by sod; 11-10-09 at 12:05 PM.
 
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11-10-09, 10:36 PM   #4  
If the head gasket is leaking it is taking in extra air and/or not pulling in enough fuel for proper combustion. So ya.. the bad head gasket could be causing the lean condition. You shouldn't have a problem replacing the gasket. Clean out the carbon deposits and gasket mating surfaces. Make sure you get the proper torque values and use the star pattern when tightening the head bolts.

 
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11-11-09, 04:04 PM   #5  
No luck

Replaced the head gasket and still a lean running condition. We torqued the head bolts at 200 inch/lb, using the star pattern and going at 50 inch/lb intervals.

Could some one with a current manual for the Tecumseh engine number hmsk80-155386v, engine family number VTP318U1G2RB please check to see if this is the proper torque values. The manual we used showed this to be the proper torque, but I wonder if it has been superseded by a Toro service bulletin.

Thanks for the help.

Ron

 
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11-11-09, 08:40 PM   #6  
So what you thought was an air leak was probably just warm cooling air coming from the blower thru the head fins? You rebuilt the carb.. did you use the proper float setting? is the dampener spring on the float needle installed with the open end towards the choke/intake? And try running the engine with the gas tank cap off or loosened. Could just be a clogged cap.

 
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11-11-09, 08:56 PM   #7  
You still have either a "leak" (as in sucking air) or the carb is dirty.
Your leak could be carb to intake, intake to engine.
You said you did a rebuild of the carb, but did you soak it in a carb cleaning soaking solution and blow it out with compressed air? This needs to be done to fully clean the carb.

 
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11-12-09, 06:18 AM   #8  
Yes, I did soak it in carb soaking solution. I will try the gas cap suggestion first, and then replace the intake gasket if that doesn't work. I replaced the gasket from the carb to the intake when I did the rebuild. The way its giong I will have a complete rebuild done, piece by piece, before this is done

Thanks for the help,

Ron

 
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11-14-09, 12:25 PM   #9  
It is not a gas cap problem. Did you also soak & clean the main jet?

 
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