I took our Ariens mower out of the shed last week to give her some love. We inherited the mower from Laurens Dad when we bought the house. It had sat in his garage for at least 3 years as their backup mower.
I took the blade off, sharpened it, cleaned the spark plug and air filter and put them back in. Then after a lot of pulls on the recoil starter it finally sprung to life with a sputter and didn’t sound right at all. After a few minutes it cut out for some unknown reason. I of course didn’t do the proper maintenance to put the mower to bed for the winter so I was hoping this wouldn’t happen.
Every time I tried to mow the back lawn when I got to the corner and turned the mower it sputtered and died. If I tilted the mower forward a bit it sometimes saved the stall and ran but that is no way to mow a lawn. I figured it was bad gas from sitting all winter but I had topped up the tank with fresh gas so who knew. At this point I had the oil hot enough to do an oil change so I did that too but I knew it wouldn’t help the problem. Oil won’t make the mower stall unless it’s way too full which the machine wasn’t.
Some internet reading suggested I clean and inspect the carburetor (where gas and air mix before being combusted) and possibly rebuild it. I didn’t even know where the carburetor was so I had to download a bunch of manuals. I started with the Ariens manual for my mower serial number 911014. But mowers can have multiple engines installed on them so I had to go get the engine serial number to look that manual up too. It was a Tecumseh TVS120.
After watching some videos of guys cleaning carburetors on the internet I figured I should be able to do that too.
I found a local Ariens shop close to work and gave them my engine number which they looked up the carburetor number from.
The rebuild kit was $6, so was a can of carburetor cleaner from Canadian Tire and I was off to the races disassembling everything and trying to get to know the engine so when it came time to put everything back together I would remember what spring goes in which hole, etc. A camera helps out a lot with these types of things!
To get the carburetor off the engine and onto the bench you have to do all this and not lose any parts:
- Unbolt the gas tank from the engine (3 bolt head screws)
- Disconnect the gas line from the tank, catch the overflow and drain the tank – set aside
- Disconnect the plastic air filter first from the carb assembly (blot head screws)
- Now disconnect the carb assembly from the combustion block (#3 philips machine screw with lock washers)
- Disconnect the spring and governor wires from the throttle plate, you’ll have to twist the carb assembly around to do this. Take a picture so you know what goes where!
- Pull off the gas line at the connection (I had to cut mine, there was plenty of line left to put it back on again)
- Pull off the prime bulb connection – pull hard it will come off.
The carburetor assembly is now free from the engine. During my disassembly I noticed the connection to the combustion block seemed kind of loose when I took it off so I decided to replace that gasket to get a good seal when I reassembled ($2 part). I probably should have replaced the lock washers too but I didn’t want to go out again for 2 washers so I’ll recheck the screws now and then to make sure everything is ok.
After getting the carburetor off the engine and onto my work bench everything was easy to do after that. Just unscrew the brass bolt at the bottom of the float bowl and pull everything apart very slowly so you see how the parts all fit together and how they need to go back in. If you are going to attempt this and don’t have much experience be sure to have an assembly drawing with all the parts exploded out in case you get lost.
Don’t mess with the welch plugs unless you think something behind them is the problem. My kit didn’t have any new welsh plugs and things weren’t horribly sludged so I didn’t take them off.
The problem in my case was that the float had fluid inside of it. When I took it off and shook it I could hear the fluid sloshing around. With fluid in it the float sits low in the fuel bowl and lets in more fuel — even though the fuel bowl is full — causing the engine to run rich and choke out since its not getting enough air.
I also knew I flooded the engine since the last time I tried to start it up a bunch of gas gushed out the bottom of the combustion block (thing with fins and a spark plug in it).
Replacing the float part was much easier to fix than the mass of tar and varnish I was expecting to be in there.
Using the parts in the rebuild kit and another trip to Cliffs to get a new float ($8 part, which is plastic now instead of brass) I was able to clean out and rebuild the carburetor. This involved a new fuel seat washer, new pin and arm and a new gasket to seal the float bowl. You’re not supposed to reuse the float bowl gasket, but if it’s not nicked or deteriorated I’d say go ahead. A little engine oil makes it go on easy. My kit happened to have a new one in it.
The engine started up on the first pull.
She smoked quite a bit as the engine was flooded because of the previous bad float. But I should be able to get by for another summer or so.
- Tecumseh Carb Cleanup – With Pictures
- Tecumseh Carb Drawings and Tips
- How To Rebuild A Tecumseh Carburetor
- Important to install the clip for the pin correctly – otherwise you could flood the engine, even with good gaskets and floats.
- Ariens Owner Manuals
- Ariens Model: 911014
- Tecumseh Engine: TVS120
- Carburetor: 632078A
- Carburetor Rebuild Kit: 631021B