Engine Backfires

bill18163

Member
Joined
Jun 10, 2020
Threads
4
Messages
14
I have an old Ariens snow blower that has an 8hp Tecumseh engine. It's about 25 yrs old. I've kept it in good shape by keeping up on replacing parts as needed but it backfires a lot. Mostly when you are stopping it and it will put out a pretty loud bang at times. But it will do it also when starting but not as bad as when stopping. Once it it running it is mostly OK with a hiccup now and then. If I knew what was wrong I would do some work on it since it would be something to keep me busy during this virus problem. I'm retired and at home most of the time. Could someone offer up an idea on what might be causing this?
 

Rivets

Lawn Royalty
Joined
Mar 11, 2012
Threads
55
Messages
14,765
Backfiring through the muffler or carb? Makes a difference as to how to proceed. I’m thinking valves not closing properly or carb running rich. When you post back include the model and spec numbers, I’m think either an HH80 or HM80 engine. Waiting to hear back.
 

bill18163

Member
Joined
Jun 10, 2020
Threads
4
Messages
14
Yes it is a HMSK80(155526S) and it backfires through the muffler.
 

Mower King

Well-Known Member
Joined
Sep 19, 2018
Threads
20
Messages
663
If you can put an inline fuel shut-off on it, shut off the fuel and let it run dry and stop running....shouldn't backfire then. I did that to my snow blower but, just so it would start up when the snow flies every winter after setting spring, summer, fall and most of the winter every year!
 

Hammermechanicman

Lawn Addict
Joined
Jan 10, 2020
Threads
55
Messages
3,526
Could be a few things. Fouled plug misfiring at times. Worn exhaust valve guide and valve not sealing sometimes. Running too rich. If it has points they could need attention. Carbon buildup in cylinder head hot spotting.
 
Top