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MTD 4.5 HP 21" snow blower won't start


z_johnq's Avatar
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Join Date: Aug 2011
Posts: 53
NJ

07-07-12, 04:18 PM   #1  
MTD 4.5 HP 21" snow blower won't start

Hi,

I have this machine for years but not to use at all in the past 3 years. Now I'm trying to clean up my basement.

The blower worked fine before but there might be a design problem: the snow it blows comes back and stays at the choke of the carburetor, which makes the carb and, maybe, engine rusty.

But after I cleaned it up: taking the carb off, used carb cleaner and compressed air to rinse and blow through all the jets of the carb but I have not used the rebuilt kit to replace some of the parts yet. Because the needle looks perfect and the rest of the carb looks fine too. I also cleaned the fuel tank and hose.

I sprayed the carb entrance and then tried to start the engine. I started and ran for about 20 sec and then died. It means the fuel in the tank cannot reach the carb. I did a few times like that and the engine never failed to start but never kept running. There shouldn't be problems with sparks and compression.

I suspect some sort of leak somewhere. I noticed the lower part of crankcase is bolted to the upper part but there is some clearance (slightly less than 1/8") between the 2 parts and they are not perfectly sealed. Is that normal?

Thanks in advance.

 
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Pilot Dane's Avatar
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07-07-12, 05:35 PM   #2  
It sounds like you need to disassemble and clean the carburetor. While you're at it I would drain the fuel tank and clean it and the fuel line out to remove any varnish or dirt that may have accumulated during the three years it was sitting.

Post a picture of the gap you mentioned in the crank case. I doubt it's really the crank case since you said the engine ran before you put it away three years ago and it ran for 20 seconds when you recently tried it. If the case were truly split I imagine you'd also be mentioning bad sounds and oil leaking.

 
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07-07-12, 06:17 PM   #3  
Not to seem rude, however, I live in Missouri and it is 110 degrees on my patio as I post this so please bring the snow blower and an appropriate amount of snow for testing and I will fix it, this offer does not apply beyond September. Have a good one. Geo

 
z_johnq's Avatar
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07-12-12, 10:33 PM   #4  
I agree with Pilot Dane. You're right about the engine wouldn't have run for a moment if there was leak in the crankcase. In fact, I've cleaned the carb already but without replacing any parts, and dumped the old fuel, replaced it with new.

There is something more. I punctured the prime by accident as trying to clean the tube leading to the carb. Now as I press the prime, I can see some gas squirt out from one of the holes in the carb; also I can see gas dripping from the bottom of the bowl, which means the gaskets between the bowl and carb body is gone. Somehow the fuel reaches the carb but may not enter the carb normally (the engine still runs a few seconds then dies).

I am really confused about what's going on. I even block the choke door with some tape to help it draw gas as I pull the starter but no luck.

Thank again for your reply.

 
Pilot Dane's Avatar
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07-13-12, 05:01 AM   #5  
If you have gas dripping out of the bowl I suspect that the engine is flooding. Possibly a stuck or improperly adjusted float/valve inside the bowl of the carburetor. This would also explain why your efforts to get more fuel to the engine are not working.

 
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