Troy Bilt Snow Blower - Engine Surging

[l008com]

This year when I fired up my snow blower for the first time, the engine was a little funny. It surges kind like the choke is on, but it does this with no choke on. And under no load, if I put it on half choke, it kind of smoothes out.

We just got a big storm so I was clearing my driveway and what was interesting was that the machine would surge like crazy UNLESS it was chowing down on snow. Under snow load, the engine would smooth right out. Then as soon as it was done, it would start surging again.

It also conks out at about 25% throttle, so you can't leave it idling at "turtle" while you go clear off a car.

This behavior is all new. This is a 5 year old blower and it has always run great before this. I always change the oil ever spring. It did have half a tank of stabilized old gas in it from last winter. But once I burned through that, I put in fresh gas and the engines behavior was exactly the same.

The last thing I did was put a good amount of sea foam in the current gas, though I haven't used it yet so none of that has actually gone through. And I was planning on replacing the spark plug today for good measure, and hoping between those two things, one would be the fix.

Here is a clip of it surging under no load:
https://www.youtube.com/watch?v=E4s6obZD8zQ

 

[Scrubcadet10]

Engine surges when the air fuel mixture is lean. More air than fuel.
So you either have a fuel blockage, or a vacuum leak sucking in air.
I would be sure fuel lines arent blocked.
You may try running it with the gas cap loose also, but a plugged cap vent normally doesnt cause surging.
The most likely is just a carburetor cleaning will fix it.
To me it looks like the engine is a Honda or Honda clone...

this video should show you how to clean it, if it is a Honda.or clone https://www.youtube.com/watch?v=uAHdhuDpeKw

If you can get any WD40 in a trigger pack (no aresol can) and spray around where the carburetor mounts to the engine, if it revs up when you do that you have a vacuum leak. Usually a tore gasket.

 

[l008com]

Engine surges when the air fuel mixture is lean. More air than fuel.
So you either have a fuel blockage, or a vacuum leak sucking in air.
I would be sure fuel lines arent blocked.
You may try running it with the gas cap loose also, but a plugged cap vent normally doesnt cause surging.
The most likely is just a carburetor cleaning will fix it.
To me it looks like the engine is a Honda or Honda clone...

this video should show you how to clean it, if it is a Honda.or clone https://www.youtube.com/watch?v=uAHdhuDpeKw

If you can get any WD40 in a trigger pack (no aresol can) and spray around where the carburetor mounts to the engine, if it revs up when you do that you have a vacuum leak. Usually a tore gasket.

So why would it stop surging when it was under heavy snow load? If it was running lean, wouldn't that cause even more bogging down under load?


Also, if the problem turns out to be a bad gasket, not a dirty/clogged carb, you are referring to gasket #32 in this diagram, correct?
https://www.jackssmallengines.com/j...-storm-tracker-2690xp-2014/370-suc-carburetor

 

[Scrubcadet10]

The reason it doesn't surge when there is a load on it has to do with the governor on the engine, and it giving it more fuel.
And it smooths out when you choke it because choking it ritchens the fuel mixture (less air mixing with fuel).

Most likely it would be that gasket if it failed. But I would try cleaning the carburetor first. Especially since it dies at low throttle.

 

[bertsmobile1]

General retail mark ups are between 30% to 50% of the retail price.
So when you see a shop that is selling everything at near cost they are either in serious financial trouble & desperate for cash flow or they are very cashed up & are trying to send all local competitors bankrupt.
Both business plans have a very short life.

 

[l008com]

General retail mark ups are between 30% to 50% of the retail price.
So when you see a shop that is selling everything at near cost they are either in serious financial trouble & desperate for cash flow or they are very cashed up & are trying to send all local competitors bankrupt.
Both business plans have a very short life.

.... uh, what?

 

[l008com]

The reason it doesn't surge when there is a load on it has to do with the governor on the engine, and it giving it more fuel.
And it smooths out when you choke it because choking it ritchens the fuel mixture (less air mixing with fuel).

Most likely it would be that gasket if it failed. But I would try cleaning the carburetor first. Especially since it dies at low throttle.

So I replaced the spark plug, since its only $2.60, but that didn't help. Hopefully if it's a dirt issue, running through the next storm with this sea foam in there will start to make it run a little better.

Regarding spraying WD40 around the gasket to see if it has an air leak, you have to take half of this machine apart to get to the carb! It's crazy. They cover it with a metal shield, but put some of the bolts to that shield behind the belt cover, that itself is behind the chute arm. It's a ridiculous process, so I figure for now ill just leave it as is, run it through the next storm and if theres no improvement at all by the end of THAT, then I'll start taking it apart and see what I can find.

Also of note, new gaskets are like $5 on ebay. But new carburetors are like $11 on ebay.

 

[Muhammad]

General retail mark ups are between 30% to 50% of the retail price.
So when you see a shop that is selling everything at near cost they are either in serious financial trouble & desperate for cash flow or they are very cashed up & are trying to send all local competitors bankrupt.
Both business plans have a very short life.

You okay there buddy?

 

[Hammermechanicman]

Your surging problem is the idle circuit in the carb is blocked. With no load the engine will be running on the idle circuit unless the engine is near or at full throttle. Under load it runs on the high speed circuit. Watch the top of the throttle shaft when it is surging. It will be bouncing open/close with the surging. You need to clean the carb and especially the idle circuit. I see this all the time. Completely drain the fuel system at the end of the season will fix the problem in the future.

 

[AVB]

Also of note, new gaskets are like $5 on ebay. But new carburetors are like $11 on ebay.

Those are aftermarket carburetors so the performance is pot luck. But as suggested do a good cleaning and it should resolve the problem.

General retail mark ups are between 30% to 50% of the retail price.
So when you see a shop that is selling everything at near cost they are either in serious financial trouble & desperate for cash flow or they are very cashed up & are trying to send all local competitors bankrupt.
Both business plans have a very short life.

Hmmm...Maybe I should charging more. I getting my Briggs parts at 20% or more off list. By your comment instead marking them back up to list I should be charging another 30-50% GPM of suggested retail price. Now all the other parts that I don't the retail on I mark-up 35% GPM above my cost except for for my JD and Stihl parts which I do 20% GPM as I give a 10% discount to 65+ seniors.

Or are we misunderstanding what you posted?