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7/9/2025
Roberto N. Underwood
2020/01/19 15:13:48
DaveOll

Murray Snowblower Tecumseh engine

Hello. Recently purchased a snowblower and it was running. 2 months later it won't run. Has spark, cleaned carb, changed gas. Now it will pop and seems to misfire. Checked flywheel key and seems fine, though hard to tell without removing flywheel. What else can i look at?
9 comments Leave a comment
Roy
Did you try squirting gas NOT STARTING FLUID down the carb throat?
2020/01/19 21:06:21
DaveOll
No, i can though. Fuel bowl is full, and will leak if primer is pressed too many times.
2020/01/19 21:46:53
Roy
That doesn't mean the fuel is getting through to the engine. The idle circuit is likely plugged.
2020/01/20 11:38:55
DaveOll
Ok so i had the carb soaked and rebuilt. The flywheel key is good, spark is good, and plug is fairly new and tests ok. Put back together and it'll fire, sputter and die. Sometimes will backfire. Small engine place gave me a known good carb to try, as they seem baffled too. Checked valves, working and not stuck. 120 compression. Installed new carb, does same thing. A few times had the cord snap back when pulling over. Now where do i go from here.
2020/01/24 16:54:43
AVB
Compression a little high for an engine with a working ACR. IF it has failed that would explain the compression kick back. With you saying checked the valves (I assuming it is a OHV engine here) then did you check their clearances? OHV engine tends to open valve clearance to point that an engine can't breathe properly. Also disables the ACR system.
 
It kinda sounds like a failing ignition coil. A weak or failing coil can have good spark outside the compression environment but fail once under the compression load.
2020/01/25 08:23:15
DaveOll
Thanks for the response. At the advice of a small engine shop i pulled the plug and watched the valves open and close while turning it over. I did check spark with a tester. It jumped about 3/4 inch, so assumed it was good. Plug resting on frame sparked well too. Not sure what ACR is.. it is not OHV.
2020/01/25 09:38:18
AVB
An ACR is an Automatic Compression Release which 95+ engines have.  Even on L-head it is still there. which you engine appear to be bad as the initial compression is too high. L head engine are right opposite on valve wear as the clearance close up leading to loss of compression.
 
With coil's spark able to jump 3/4" it should be; unless, it has an internal timing problem.
2020/01/25 10:27:18
DaveOll
So most likely its an anchor now? Likely the best 300 I've spent! I think timing is all gears and should not go out, unless its stripped or slipped somehow. 🙁
2020/01/25 13:28:23
AVB
DaveOll
So most likely its an anchor now? Likely the best 300 I've spent! I think timing is all gears and should not go out, unless its stripped or slipped somehow. 🙁

I think mis understood what I said as I was referring the coil's internal timing.
2020/01/25 15:44:03

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