# Troy Bilt 5024 Snow Blower Surging - Replaced Carb



## MGroothuis (Jan 7, 2003)

This surging has been a problem for a while now. It only runs "smooth" unless I have it at half choke. Wide open (no choke) it runs at very low idle, but doesn't die. I finally bought an entirely new carb and replaced it today to have it run exactly the same after putting it back together. I assume it's running lean, but I'm no expert. Any advice? Bad gasket between the carb and the motor? Thanks.


----------



## Sir Thomas (Dec 7, 2013)

Check the governor spring. Do you know where the idle screw is?


----------



## MGroothuis (Jan 7, 2003)

To be perfectly honest, no I don't know where the idle screw is. I'll have to look at the old one. I really thought this would fix the problem. I've also been told to mist a little carb cleaner around the gaskets while running. If the engine revs a little, there's an air leak. ?


----------



## Sir Thomas (Dec 7, 2013)

MGroothuis said:


> To be perfectly honest, no I don't know where the idle screw is. I'll have to look at the old one. I really thought this would fix the problem. I've also been told to mist a little carb cleaner around the gaskets while running. If the engine revs a little, there's an air leak. ?


What's the make and model of Carburetor. Again check the governor. When it's surging does the governor arm move in the same pulse?


----------



## 30yearTech (Sep 14, 2006)

If the surging smooths out with the choke, then the mixture is too lean. It could be an air leak at one of the gaskets. If it smooths out when a load is applied then the pilot jet could be plugged. I have run across new carburetors with plugged pilot jets, rare but it does happen.

The pilot jet is that little plastic piece underneath the idle stop screw. You can remove the idle screw and pull the pilot jet out and make sure all the passage ways as well as the jet are clear.


----------



## Sir Thomas (Dec 7, 2013)

MGroothuis said:


> This surging has been a problem for a while now. It only runs "smooth" unless I have it at half choke. Wide open (no choke) it runs at very low idle, but doesn't die. I finally bought an entirely new carb and replaced it today to have it run exactly the same after putting it back together. I assume it's running lean, but I'm no expert. Any advice? Bad gasket between the carb and the motor? Thanks.


Anytime you replace a carb or even doing a rebuild, you should always replace the gasket to the intake port. Remember, the engine is sucking through the carb so if there is any kind of leak between the carb and the intake valve, then it's going to run lean.
As far as the adjustments, it comes from the factory with the standard setting which I think is about 2 1/2 turns on the jet screw. The idle screw and jet screw is two different things. The idle screw limits the return on the throttle (idle speed). The jet screw regulates how much fuel enters the chamber per volume of air. 
If you have determined that there is no leak, start engine with the air filter on and let it warm up at half choke then turn the idle screw in until it runs at a fairly high speed. Turning the screw clockwise makes it run lean. Turn it until it starts to die and note position. Turn it counter clockwise (richer) until it starts to sputter (too rich) and note position. Find the halfway point and set it just a little on the rich side of the halfway. Turn the idle screw back out until it runs low enough without stalling. Now try to run it with the choke fully open and see if it runs smooth. You make have to make some fine tuning on the jet screw but you shouldn't have to turn it much at all.


----------



## 30yearTech (Sep 14, 2006)

Sir Thomas said:


> If you have determined that there is no leak, start engine with the air filter on and let it warm up at half choke then turn the idle screw in until it runs at a fairly high speed. Turning the screw clockwise makes it run lean. Turn it until it starts to die and note position. Turn it counter clockwise (richer) until it starts to sputter (too rich) and note position.


The carburetor pictured, has NO MIXTURE adjustments. The only adjustment that can be made is the idle speed stop screw and that does not change the mixture.


----------



## MGroothuis (Jan 7, 2003)

Sorry, I've been absent for a while now that the snow is melting around here. It'll be nice to work on this outside in the sun. I think I'll start with the gasket behind the plastic panel between the carb and the motor. Strangely, that's the only gasket not included in the replacement kit I bought. The old one looks pretty smashed.


----------



## epor (Mar 18, 2015)

Came across your thread searching for something else, and registered just to let you know how I fixed it after battling this problem over the winter. 

These engines and carbs are not adjustable. The surging means it is running lean, probably because of build up somewhere in the carb not letting enough gas in. 

Do a google search for "Professional Shop Manuals - Troy-Bilt" The site should be mtdproducts com. (I can't post links yet apparently.)

Check out the service manual for your engine on how to properly disassemble the carb including the float, the jet, and the fuel measurement port at the top. Yours looks like the 61/65/70 Series engine. 

The first time I took it apart, i was being gentle and just ran carb cleaner through everything. Same problem when I put it back together. 

Second time I took it apart, I ran some very small drill bits through all of the ports inside the carb and through all of the little holes in the jet tube. I didn't have anything small enough for the fuel measurement port, so I ran a piece of thread through, and then rubbed it back and forth. 

After that, worked like a charm. 

Worst case scenario, you should be able to get a replacement carb from ebay or amazon for about $30. 

Another note, these engines seem to have gas tank vents through the threads of the gas cap. If you twist on the gas cap way too tight, air will not be able to get into the fuel tank which will not let fuel run into the engine. I figured that out when it would run great for about 5 min, and then start to falter. 

The gaskets should be fine to reuse as long as they are in good shape. Some people will say "DON'T USE METAL TO CLEAN THE CARB PORTS!!!" As long as you are cleaning and not drilling the holes larger or putting in huge scratches, it is fine. 

Good luck!


----------

