Export thread

I was given a Yard Man mower that wouldn't run, carburetor was beyond repair. Engine is model 122T02-0377-B2. Ordered carburetor #799872 ( aftermarket, not OEM ). It will start and run fine with a shot of starting fluid but won't start again without another shot. Replaced primer bulb, cleaned the air passage and screen in the filter box. Is the throttle valve supposed to be fully open when starting and is the primer the only thing that chokes it?

Don't know for the throttle position.

When it is running it run fine/steady/smooth ?

All gaskets in good shape ?

Can you see fuel shoots inside the carb when using the primer bulb ?

" Is the throttle valve supposed to be fully open when starting and is the primer the only thing that chokes it? "

The primer should give fuel to start, and throttle valve is always open if you don't have a throttle cable, check that you have fuel going to the carb, fuel is the problem.

The primer bulb is the kind with a hole in it. It doesn't fill with gas like the ones on a 2 stroke, It pressurizes the fuel bowl to force gas out. Took the carb back off and it was full of gas. It runs fine once it's started.

Sounds like you have gotten an OEM carb that Briggs rejected because it was defective.
There are a lot of them out there.

The thing that has me stumped is the fact that it runs fine after I get it started. No signs of running out of fuel. I even took the bowl off and blew air through all of the passages to make sure they were open. My next step will be to order an OEM carburetor. One other thing, the new carb came with a plastic spacer block which I did not use. Don't know why it would be needed if the old carb didn't have one.

The carb has 2 fuel circuits
1 for starting
1 for running
The running circuit on yours is working fine
The starting circuit on yours has a blockage.
Not sure which exact carb you have.
on some you can clean the starting circuit , on others the fuel holes are behind covers & plugs so you have to buy a rebuild kit if you want to clean them out properly.
Most rebuild kits are more expensive than a cheap replacement carb.
Most really cheap replacement carbs are defective which is why they are really cheap.
All of the aftermarket parts wholesalers, Oregon, Prime line, Rotary & Stens do replacement carbs.
They are a little bit more expensive than what you see on Evilaby, Craigs & Amazon, because they get tested properly ( that costs money ) and carry a warranty ( that also cost money )
People like to play lotteries and it seems the Parts Lottery is becoming more & more popular every minute.

KHO................ I know the engine you have well.... That block comes with a few different HP's but the carbs are the same ..... Except the EZ start versions.... AKA Auto choke without the primer bulb......

Bert is right, you might have gotten a defective carb....... I might have a video showing that carb with all the different holes to clean out ............

You might have something going on AFTER the carb....... The O ring that goes on the intake tube might be worn and the intake itself might be loose....... Or the carb plate that the carb bolts to is loose..........

Also try a brand new spark plug ,,,,,,,,,,,,,,,

Let us know Mon Ami ~!~!

I'm leaning towards a defective carburetor. I should know better since I had the same problem with a Craftsman chainsaw. Ordered a Chinese carburetor that didn't work, ordered an OEM one from Sears and it started right up. I noticed when I took the bowl off of this carburetor that there were brass fillings in the bottom. I doubt that they came from the fuel tank. The good news is I'm only out $20 and I can still use the air filter, shut off valve and spark plug that were included. I'm going to order an OEM carburetor and I'll post the results later. The hard thing about buying parts nowadays is you can't even be sure where the OEM ones are sourced .

Boudreaux In Eunice La. said:

KHO................ I know the engine you have well.... That block comes with a few different HP's but the carbs are the same ..... Except the EZ start versions.... AKA Auto choke without the primer bulb......

Bert is right, you might have gotten a defective carb....... I might have a video showing that carb with all the different holes to clean out ............

You might have something going on AFTER the carb....... The O ring that goes on the intake tube might be worn and the intake itself might be loose....... Or the carb plate that the carb bolts to is loose..........

Also try a brand new spark plug ,,,,,,,,,,,,,,,

Let us know Mon Ami ~!~!

Click to expand...

I would think that if there were a leak after the carburetor I should have a surging problem. It runs like a top when its running.

kh0432 said:

I would think that if there were a leak after the carburetor I should have a surging problem. It runs like a top when its running.

Click to expand...

It'll run with unmetered air But you gonna run lean..... check your spark plug for color........

Installed an OEM B/S carburetor. Had to push the primer a lot more than 3 times to get it started. I can also shut it off now and it will start right up again without priming.

Nice, that's way better

So new working carburetor.
Gaskets are new ?
Primer bulb is new ? Do you see good amount of fuel pouring into the carb when priming ? Perhaps it's a bit weak.
I used this style primer on a briggs 650, 2 times when warm weather is there 3 times otherwise and it's fine !

Don't know where I read it but someone said the air filter housings are prone to warping and put on 2 gaskets between the housing and carburetor. Did that and primer squirts fine now. Push bulb 3 times and starts right up. Thanks for all the input.