Export thread

Hello all,
I'm new to the site & am looking for help. I recycle used mowers & string trimmers for anyone needy & sometimes sell too. I have a B&S 6.0 hp that won't run with an air filter installed. The numbers are: 11A602 0125 E1 001012 FA. It is an overhead valve engine. So far I've tried: Rebuilt carb., set the valves, replaced main jet, reset governor, reset air gap. The plug is dry & black. I also pulled the head & scraped the carbon off the piston top & cleaned the valves.
This would suggest a rich condition but there are no adjustment screws on the carb at all. This engine starts fine but sputters when the air filter element is out. Put it in & it dies. It was doing this when I got it, so I haven't hurt anything, but I haven't fixed it either.
Mower personnel told me if the main jet didn't fix it, to bring it in. That kind of defeats the purpose. I don't want to spend a fortune on it to give away. I would appreciate any input you could give me. Thanks in advance.

pumper

Check for an air leak between the carb & engine block... a slight restriction, (with filter), could be enough to lean it completely out.. :smile:KennyV

KennyV,
After rebuilding the carb, all gaskets were replaced with new. I saw no indication of gouges, chips, etc. on the surfaces. Would spray on carb cleaner show a leak? Thanks, pumper.

pumper said:

KennyV,
After rebuilding the carb, all gaskets were replaced with new. I saw no indication of gouges, chips, etc. on the surfaces. Would spray on carb cleaner show a leak? Thanks, pumper.

Click to expand...

Yes if it pull it in...
it will richen up the fuel mix, you will hear it... :smile:KennyV

Hey there! WELCOME to LawnMowerForum! :biggrin:

I moved your thread to the Small Engine & Mower Repair Forum. You'll get a better response there. :thumbsup:

Hi,
Well, I sprayed carb cleaner around the intake gasket & had no change. I removed the air filter backing (which connects to the breather assy.) & it ran fine. A little too fast I think. Blocked the carb throat completely with air filter & nary a flutter. Put it all back together, it died.
I've cleaned the air breather assy. out, so is it possible to have a timing or governor issue? Gettin' close to trash day! Thanks, pumper.

You said you rebuilt the carb but the seal in between the carb and the back of the air cleaner box could have sprung a leak. I have seen this happen many times with engines like this. If it is not perfect then it could make it quit. Did you try to put the box together without the filter in it and see what Happens?

jteuban May be on the right track... put it together without the filter element, like he suggested...
There may be a kill switch incorporated with the throttle linkage that some how is getting shorted out when you assemble everything... Look for a wire and see that it is not shorting out the coil... :smile:KennyV

The thing that sticks out for me is the plug read. Black means rich. So I might ask how did you clean the carb? Could you have used something in the main jet that made the hole larger?

It will be leaner without the air cleaner and if it runs that way, the air cleaner is making it too rich. What sort of air cleaner is it? One of those foam ones? They're supposed to be lightly oiled, but will choke the engine if you use too much oil. If that's not it, then there is something wrong with how you assembled or adjusted the carb.

jteuban said:

You said you rebuilt the carb but the seal in between the carb and the back of the air cleaner box could have sprung a leak. I have seen this happen many times with engines like this. If it is not perfect then it could make it quit. Did you try to put the box together without the filter in it and see what Happens?

Click to expand...

Hi all,
The seal you refer to was new. I put another new one in & it did the same thing. With the box assembled with no air filter, it stays running but doesn't sound quite right. A little bump on the governor & you can see a puff of black smoke. Thanks.

KennyV said:

jteuban May be on the right track... put it together without the filter element, like he suggested...
There may be a kill switch incorporated with the throttle linkage that some how is getting shorted out when you assemble everything... Look for a wire and see that it is not shorting out the coil... :smile:KennyV

Click to expand...

Hi all,
It doesn't die like a short. More like shut off air supply. Thanks.

Mini Motors said:

The thing that sticks out for me is the plug read. Black means rich. So I might ask how did you clean the carb? Could you have used something in the main jet that made the hole larger?

Click to expand...

Hi all,
I soak all parts in carb cleaner for at least an hour. Blown out with compressed air. I installed a new main jet because I don't know what a previous owner might have done. Thanks.

oldyellr said:

It will be leaner without the air cleaner and if it runs that way, the air cleaner is making it too rich. What sort of air cleaner is it? One of those foam ones? They're supposed to be lightly oiled, but will choke the engine if you use too much oil. If that's not it, then there is something wrong with how you assembled or adjusted the carb.

Click to expand...

Hi all,
Air filter is paper type. There are no adjustments to the carb available. Please refer to post #6. Thanks.

It sounds like the air cleaner is pluged. Did you clean it or replace it. If you cleaned it try a new one.

reynoldston said:

It sounds like the air cleaner is pluged. Did you clean it or replace it. If you cleaned it try a new one.

Click to expand...

Hi,
Filter is new. I don't clean the paper type.

pumper said:

Hi,
Filter is new. I don't clean the paper type.

Click to expand...

Hi,
Sorry. Just read that post again. Did you mean the filter or the air breather assembly? The filter I replaced, the air breather assy, I cleaned. It rattled like one I took off another engine. Also cleaned the pipe from there to the back of the air filter box.

I have an approximately 25 year old mower, and I just did an overhaul. (Re did carburetor, replaced spark plug, replaced air filter, changed oil, cleaned carbon off the piston/cleaned the head area, and changed some gaskets) When I started it up after all this, the air filter wasn't in, and it started up just fine. I thought everything was all good, so I went ahead and put the air filter in and put the cover on. i tried to start it, but it wouldn't start. So I went back to see what I did differently. I figured it was the air filter, so I took it out, and after a few tries and some black smoke, it fired up. I then went ahead and put the filter and filter cover on and it ran fine. So I turned it off, and tried again with the filter. It didn't start. So I came on this site, and I think that the diagnosis would be a leak between the filter and the carburetor. There is a partially rotted line that does just that. I just wanted to know if that little leak could be the cause of the problem. And if it is, how do I go about fixing it?

Dimension your air filter is partially or full clogged. The black smoke is an indicator the the engine is flooding when you put the air filter in place. It is acting like a choke and not letting air in. Replace it.

I once washed out a foam air filter with gasoline, soaked it with oil and squeezed it out and the motor would not start. Maybe I didn't have it dry enough after the gas and the gas and oil filled the open pores. I don't know, but it was weird. It worked later. Another reason for unexplained non-starting is if the governor linkage and springs get bent or disturbed when removing the air cleaner or carb.

Do these have carb inlet valves or float settings? Sounds like classic flooding?