lawnmower -- May I wash paper air filter? Only runs when pumping red bulb?

[mm]

lawnmower -- May I wash paper air filter? Only runs when pumping red bulb?

A) My Sears walk-behind mower uses a pleated paper air filter shaped sort of like the inside cardboard of a toilet paper roll, but shorter. Paper inside with a plastic skeleton around it. I can't go buy another one now, and someone told me I could wash this one, even though it's paper. Is there any truth to that?

B) I lent it out and my friend didn't use Sta-bil, and probably didn't run it for a month or more, when summer was over. Now, it won't start for him, and when I press the red rubber bulb 5 times and pull the rope, it will often start and run for 5 seconds. If I get to the red bulb in time, before it stalls, and I press the bulb 2 or 3 times a second, I can keep the engine running as long as I do that. On Friday, I pressed the bulb for about 30 seconds and then the machine ran on its own 60 seconds until I turned it off, but now that I'm not at my friend's house, and I'm at my own house, I've pumped the red bulb and kept it running for 90 seconds, but a few seconds after I stop, it stops too. The weather's not as warm as it was Friday.

It also runs when I spray starter fluid in the carburator throat.

Is Gum-out carburetor linkage spray, which can also be sprayed down a carburetor, worth spraying into the gas tank? I don't think spraying into the carb will do any good, will it?

What about gum-out fuel injector cleaner? That's meant to go into the gas tank and disolve deposits wherever the gas goes. Likely to work here?

Is Sta-bil going to do any good at this point? I thought that just stops gum from forming?

Can I use all 3?

Is there any point to any of the three? That is, does pressing the red bulb bypass the bowl and tube to the primary jet, and is that where the problem is?

It's getting cold out and I have a recently broken arm, and recent abdominal surgery, but I really want to fix this, and mow my lawn with my own mower, before winter comes.

Any help is appreciated.

[Bob F]

A plugged filter would make it run rich, not lean. If taking the filter off doesn't solve it, you will know the filter is not the problem. The real problem is probably a gunked up carb, which may require disassembly to clean.

You should first have dumped and replaced the gas with fresh gas. Do it if you haven't and try again. Some kind of carburator cleaner could help, but it's no sure thing.

Sometimes, with fresh gas, just starting it and keeping it running for awhile by using the primer or choke will get things cleaned out enough so that it will keep running.

[ransley]

cant wash paper filters, you can buy a new one, carb need a pro cleaning. Only maybe over winter will a carb gum up, but does it even have a fuel filter, it may not be his fault but went bad over years.

[mm]

OK I figured not but my friend was convincing. It's filthy but I'm not saying it's the reason the engine won't run more than 8 seconds.

Well, thanks to you and Bob F.

It was cold and windy today, but I planned on removing the carb and cleaing it in what is apprently professional parts cleaner (though it doesnt seem as strong as the stuff I bought 45 years ago. An old guy at a motorcycle shop told me they don't sell the good stuff to anyone anymore.)

But unlike the Briggs and Stratton engine, for this Sears, it looked like the carb woudn't come off easily (the muffler was in the way of one screw) especially with the recently broken arm weak and hurting when I bent it in most directions)

So I took off the bowl and most of the gas came out through the screw hole in the bottom of the bowl, but what was left looked terrible.

The little holes in the screw were fine and I think the tube that goes up to the carb is clogged. Thursday, Friday, and Saturday are supposed to be in the 60's I think, or at least sunny. I'll do something more then.

What does the red bulb do anyhow? It sprays gasoline in the throat somewhere but where does the gas come from in most engines, which have bowls? From the bowl? From something closer to the gas tank?

I have a book on repairing lawnmowers, but I coudn't find this detail.

(I have to mow my lawn once before winter, and it's either fix my machine or borrow my neighbor's. He and I aren't getting along and I don't know if he'll like me more if he does me a favor, or if he'll think I'm indebted to him. Plus if I don't clean my mower out now, it will be much worse by spring.

[Matt]

Running lean, of course.

Check for air leaks: air filter not seated properly, missing carb gasket on some models.

Plugged carb jet. If it is only partly plugged, carb cleaner in the gas tank should clear it up.

Maybe you could cover part of the air cleaner with plastic temporarily to get a choke effect.

[Phisherman]

Don't thik a paper filter should ever be washed. Chances are good Sears sells these online.

You can use a carb cleaner (in the carborator) to see if that makes any difference. Gum-out can make the engine run rough for awhile.

Empty out the gasoline and fill it with fresh gas.

[Logic316]

NO. I tried washing the paper air filter for my car's engine once, and one day it just fell apart letting leaves and other crap in. You can wash out plastic foam filters, though. As for your other problem, the gas is just probably old and contaminated, and the carburetor may have some varnish. You will need to flush out the gas tank (spray some carb cleaner in there to get everything out, and use a siphon pump to make things easier) and spray some carb cleaner around the throat of the carburetor. As a future tip, if you let gas get too old you can make the motor run reasonably well by spraying some starting fluid into the gas tank.

- Logic316

"Thieves respect property. They merely wish the property to become their property that they may more perfectly respect it." -- G.K. Chesterton

[mm]

That's a darn good idea, about the plastic. I don't know why they don't put chokes on lawnmowers anymore. Or throttles either on many.

Then people wouldn't have to listen to the loud engine when the lawn is short or sparse.

The choke idea should help some other time even if it doesn't work this time.

[Matt]

Thanks.

You said you sprayed starting fluid in the the throat. Does that mean you've been trying to run without the air cleaner? I wouldn't expect that to work, because the air cleaner is supposed to cause a pressure drop that will produce a choke effect when running normally.

Once I tried to run an old Briggs without the air cleaner gasket and couldn't get it to start---it was running too lean until I put the gasket back in.

If you can get it to run, you can get flow through the jet(s) and dissolve gums and so on that might be obstructing the jet(s).

[NickySantoro]

Don't wash the filter. Replace it. My old mower used that type and they were cheap enough at Kmart and HD.

Sounds like the carb is gummed up. BTDT. Remove all gas. Get a bottle, not spray can, of carb/fuel injector cleaner. Pour about 3 or 4 ounces into tank, prime it up, then try to start it. You want to get the cleaner into the bowl and carb innards. Let it sit for a half hour. Repeat then let it sit again. Add fresh gas and try to start. It should start now. Add about an ounce of cleaner to the gas and let it run for a bit. I've brought a couple back from the edge this way and only had to disassemble the carb on one. HTH