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Hi Follks,

I am not the best at fixing small engines so I am trying to learn.

I have a Troy-Bilt Zero turn with a Kohler 7000 Engine and Walbro Carb. The engine started to sputter and die when I ran it for 5 min. The first thing I tried is pulling off the carburetor and cleaning it, but no luck. However now I seem get engine surge right after start up which i did not notice before. So I checked the fuel pump and gas tank for blockage and it seems to be sending gas fine so no luck there. I checked the spark plugs and they seem fine. Then I took off the Carburetor, cleaned it again, and used a rebuild kit, still no luck.

I am about to put another Carburetor on it. But before I do, any suggestions?

Surging is always due to insufficient fuel for the volume of air.
So two sides to this, too much air, leaks ? or not enough fuel or both.

There is a pilot circuit and a main running circuit.
IT seems that the pilot circuit is fine but the main circuit is still blocked.
If it has an adjustable idle jet , that needs to be opened up a touch.

Thank you for the help.

If the "main running circuit" is inside the carburetor it was probably a very thin brass pipe that went down the middle, this was impossible to clean and not removable, although I stuck a wire in, shot it with carb clearner and blew it out. Around this small tube was another larger tube that I was able to remove (called a nozzel on one diagram I found), it had smaller holes through its side and I was able to clean it all out. This is hard to explain in an email. But both of these were capped with a screw/nozzel) on top that had to be removed to pull the larger tube out.

Or is the "main running circuit" somewhere else? Possibly an adjustment that might be under a cap on the outside of the carburetor?

Not being one to reinvent the wheel, this site has the best carb cleaning instructions
http://outdoorpowerinfo.com/repairs/
Some times I have to clean them multiple times.
Also make sure the fuel supply is good & strong, there are no kinks in the fuel lines, the filter is clean, the pump is connected right way round.

Using a trigger pack soak the joints between the carb and the mower with WD 40 or similar to check for air leaks after the carb.

Kohler had an date where the flashing in the heads from casting needed to be drilled out because of the oil ports. Also might check the evap hose if equipped also the carb jets needed help as well

Just replaced the carb with a new one and made sure there were no air leaks. Blew out all the hoses again. Drained the tank again. Checked evap line. It ran almost fine for two min, then started surging again. What the Heck! Any other suggestions?

Most new engine wil surge until you put it under a load only one that I haven't seen surge new is the Kawasaki. The bad casting in the head might be causing it to leave oil in the head for to long and sucking the oil causing poor running as you described. That's the update I was talking about.

Well the issue ended up being the carburetor, I just didn't transfer a part from the old one to the new one. It's working fine now.

franktroy said:

Hi Follks,

I am not the best at fixing small engines so I am trying to learn.

I have a Troy-Bilt Zero turn with a Kohler 7000 Engine and Walbro Carb. The engine started to sputter and die when I ran it for 5 min. The first thing I tried is pulling off the carburetor and cleaning it, but no luck. However now I seem get engine surge right after start up which i did not notice before. So I checked the fuel pump and gas tank for blockage and it seems to be sending gas fine so no luck there. I checked the spark plugs and they seem fine. Then I took off the Carburetor, cleaned it again, and used a rebuild kit, still no luck.

I am about to put another Carburetor on it. But before I do, any suggestions?

Click to expand...

I have the same motor and it started surging about a week ago so i changed fuel filter, new air filter, poured stabil into gas tank and no better. Almost didn’t start a couple of days ago so I decided it was time to take carburetor off and clean or buy a new one. i watched a video on YouTube where the guy poured Techron directly into air intake and carburetor cleaned right up. I poured about 1 and half ounces in VERY slowly and mower blew white smoke back fired out the air intake and mower is running like brand new. Techron is incredible stuff, made by Chevron. Then poured about 2 ounces in my mower gas tank, running like a clock. Will probably put a couple of ounces in gas tank about once a month. Bought another bottle of Techron from Amazon to put in my pickup that has about 120000 miles on it. When the government forced oil companies to mix corn oil/ethanol into fuel problems multiplied. Be careful pouring Techron in air intake. Just about a half an ounce at a time so it doesn’t stall motor. Also after you pour some in stand back as fire shot out the air intake. It works!

If you want real fuel injection and oil cleaners, get 505CRF and 505CRO by ATS Chemical.

Approved by Scotty Kilmer.