Need small engine help - snow blower and its snowing

[sandyut]

I have a Husquavarna snow blower that has run flawlessly for years...till no and its snowing. the engine is a single piston tecumseh 9 HP. the engine revs up and down and backfires. I changed the sparkplug and swapped the gas to no improvement. if I leave the choke on slightly it settles quite a bit but that seems like a bad plan long term. I am not much of an engine guy and I am not sure what to do. I alwyas run it dry every spring so I dont think there is bad gas gummed up in there but I have no clue. Anyone have some ideas?

thanks

 

[rileybowler]

I have a Husquavarna snow blower that has run flawlessly for years...till no and its snowing. the engine is a single piston tecumseh 9 HP. the engine revs up and down and backfires. I changed the sparkplug and swapped the gas to no improvement. if I leave the choke on slightly it settles quite a bit but that seems like a bad plan long term. I am not much of an engine guy and I am not sure what to do. I alwyas run it dry every spring so I dont think there is bad gas gummed up in there but I have no clue. Anyone have some ideas?

thanks

Try putting some of that gas cleaner in the fuel never can tell it just might work, sometimes it is the simple things that work, also check your air filter.

 

[DougE]

Tear the carburetor down and clean out all the jets. I can't tell you how many times I've had to do this for people I know. That fuel just sits in the carburetor gumming everything up (especially this gasoline with the added corn liquor, which we should be drinking, not putting in our engines). I pull the carb, disassemble, soak the parts in solvent, and clean out all the holes in the jets with a welding torch tip cleaner. They run like they are supposed to when I get done.

 

[Ringer]

Yep, carb clean out time. Especially if the fuel had any amount of ethanol in it.

 

[sandyut]

ok, I will try the gas carb cleaner first for short term. Im not super good with engines, but I can replace the carb. I'll get one ordered and get to that after the storm. The repair shop wanted $80 to pick up and deliver and $100 to rebuild or replace. I found a replacement carb for $20 on Amazon. id this fix on an Echo leaf blower and it was easy and worked perfect.

thanks all!!! after over 10 years of service this is the first issue I have ever had...kinda shocked me. this thing starts first pull and run like a beast...or ran like one till today.

 

[DougE]

It really ain't that hard to pull the carb that's on it and clean it out. All it takes is some basic hand tools to take it off and disassemble. I gotta realize, though, that what seems basic to me, might not be to someone else. I think I rebuilt my first small engine when I was around 12 and since graduated to car engines. For my latest trick, I did head gaskets on my 2003 duramax diesel last year. Now that was a job I don't wish to do again.

 

[chopsaw]

Backfire out of the carb or exhaust ?
I agree it's bad gas , but if it's popping out the carb it's a stuck intake valve .
Surging could be a lean or rich condition , but if it improves with the choke on its lean . Cleaning the carb is a place to start , but if it's popping out the carb you will have to unstick the valve .

 

[forktender]

When im doubt, replace the fuel and Carb, the carbs are cheap on amazon. Go with the after market carbs they are all made in the same factory in China, all of them.

I replace carbs every spring for mower, hedgers and tillers. It saves me LOTS of grief and only takes 10 minutes each.

 

[jcam222]

Mine ran kind of wonky all year last year. I have a huge MTD gold. I had to leave the choke slightly turned a little less than run. It ran ok like that all winter but would idle a little rough at times. Heck I didn’t know you could buy entire replacement carbs so cheap. Wonder if that’s what I need too. I’m about as mechanically inclined as a newborn monkey.

 

[DougE]

Backfire out of the carb or exhaust ?
I agree it's bad gas , but if it's popping out the carb it's a stuck intake valve .
Surging could be a lean or rich condition , but if it improves with the choke on its lean . Cleaning the carb is a place to start , but if it's popping out the carb you will have to unstick the valve .

A surge can also pop back through the carb. When the RPMs get low enough the engine will try and turn backward and pop through the carb. after the engine hiccups, it'll try to turn the right way again, but most of the time it will quit. I've actually had 2 stroke motors start running backward after such a hiccup. Yes, a 2 stroke is capable of running both directions. I have an old Yamaha 2 stroke golf cart around here and there is no transmission. the starter motor starts the motor in the opposite direction when you want to back up.

 

[chopsaw]

Popping out the carb is a burnt or stuck intake valve . If it backfires through the carb , yes that could be a kick back condition when it fires .

 

[DougE]

Mine ran kind of wonky all year last year. I have a huge MTD gold. I had to leave the choke slightly turned a little less than run. It ran ok like that all winter but would idle a little rough at times. Heck I didn’t know you could buy entire replacement carbs so cheap. Wonder if that’s what I need too. I’m about as mechanically inclined as a newborn monkey.

If you can assemble an office chair from Walmart, you got enough skill to take the carb off and clean it.

 

[DougE]

Popping out the carb is a burnt or stuck intake valve . If it backfires through the carb , yes that could be a kick back condition when it fires .

I don't disagree, but it's not likely going to actually run with a burnt or stuck valve. It won't build sufficient compression.

 

[OldSmoke]

Easy things first. Go get a can of Sea Foam. Fill the tank with fresh gas and a healthy dose of Sea Foam. It might take a tank, but it can help.

Try to find clear gas also known as non-ethanol fuel. Your engine will run much better and won’t gum up. Toss in some Sea Foam to stabilize the fuel as well.

 

[DougE]

Try to find clear gas also known as non-ethanol fuel

This site shows stations that sell Ethanol free gas

 

[Fueling Around]

Star Tron is the best fuel additive / stabilizer to use YEAR AROUND in your small engines. Local small engine shop got me started using it after Sta-Bil, Seafoam, and other products failed after non season use. It does stabilize ethanol blended fuels. I use it full strength in every can. I also use premium no ethanol fuel, but still add the blue juice.
Older carbs can be completely disassembled and cleaned to remove the blue green scale from evaporated ethanol enhanced fuels.
Newer carbs have a lot of hindrances to rebuilding mostly in the idle circuit. If you cannot remove the idle mixture screw, replace the carburetor.
Oddly, surging in an engine is often caused by a clog in the idle circuit.
I think DougE knows the routine of balancing the idle circuit and high-speed circuit for a properly tuned engine

 

[DougE]

A lot of these carbs on honda and knockoffs have an access to clean the idle circuit from the top.

 

[OldSmoke]

Startron is my choice for marine diesels. It can work wonders if used at every fill. I agree this is the best for long term storage.

For cleaning, I have had good luck with Sea Foam. It doesn’t always work, but enough to try it first.

 

[chopsaw]

It won't build sufficient compression.

And that's why it pops out the carb . I'm not saying it has a burnt valve , but bad gas can cause the intake valve to hang open . It will run or try to run in that condition . I only mentioned it because he said it was backfiring . I was just asking if it was out the exhaust or coming back through the carb .

 

[DougE]

And that's why it pops out the carb . I'm not saying it has a burnt valve , but bad gas can cause the intake valve to hang open . It will run or try to run in that condition . I only mentioned it because he said it was backfiring . I was just asking if it was out the exhaust or coming back through the carb .

I agree with what you are saying, but I'd put my money on a stopped up carb. I been wrong before, and may be now, but that is mostly what I find wrong with engines that ran fine until they sat for a period of time. This ethanol fuel is hell on carbs.