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Craig D Peltier
10-12-2007, 8:38 PM
Hi my briggs an Stratton self propelled lawnmower is giving me trouble.
It starts and runs for maybe 5 minutes.Then slowly stalls out. I then wait 5 minutes or so it starts and then runs maybe three minutes.
I have changed the gas, I have checked the oil. I have checked an cleaned air filter.I have cleaned off spark plug after taking it out with steel wool and wire brush.
There is no prime bulb.There is no choke. I cant see an fuel filter either.I follow the the fule line from tank right inot motor with nothing in between (hoes is maybe 5 inches) I would think fuel but not sure?

Any ideas?

Travis Porter
10-12-2007, 9:07 PM
There are two basic types of carburetors. Diaphragm and needle/float. Check to see if you have a needle/jet adjustment screw. If you do, screw it all the way in, then screw it out 1 and 1/2 turns. Crank the mower, see if you can adjust it to where it runs properly.

If you do not have an adjustment or if the adjustment doesn't work, spend a couple dollars and buy a spark plug. Cleaning helps, but doesn't always address the issue.

If that doesn't work, if it is a diaphragm carburetor, get a carburetor kit and replace it. If it is a needle and float, disassemble and verify the float does not have any gas in it by shaking it and listening to it. If it does, replace the float. If it doesn't, verify that the paths through the needle assembly are clear with a thin piece of wire. Gunked up gas can cause gas not to flow well through it.

Good luck.

Joe Pelonio
10-12-2007, 10:07 PM
If a simple spark plug change doesn't do it, maybe hold off and borrow one from the neighbor. This weekend could be our last dry days for a while, and probably (hopefully) the last time the lawn will need mowing for the season.

Greg Peterson
10-12-2007, 10:31 PM
Sounds like a carburetor problem to me too.

Lee DeRaud
10-12-2007, 10:45 PM
That sounds like it's upstream of the carb. Check the fuel cap and make sure the vent isn't clogged.

mark page
10-13-2007, 8:33 AM
I had one of those small Honda tillers do the same thing. Drove me crazy and later found that there was a fuel filter for it inside the fuel tank on the feeder fuel hose that was partially clogging from the fuel stabilizer that I was using. That repaired the problem and I quit using the stabilizer for its fuel.
Also may check to see if the carb has a sediment bowl. Most B&S Intek engines have those and they can fill with sediment, ran into that before too.
Lee has a very valid point on the fuel cap not venting, this will affect gravity fed systems harshly (ever try to pour fuel out of a can without the vent open).
Lastly, carefully remove the carb and clean with spray carb cleaner ensuring all the ports and jetways are clean and reinstall. A tip to all, if a carb or carb kit is needed. Verify all your parts info on the Briggs website and go to Sears parts and service website. You can get virtually anything through them and they are usually cheaper than the manufacturers website. I've ordered a lot of Briggs parts through them and were in stock where Briggs parts division showed them as being discontinued or permanent backordered. Have to be careful and read all the parts notes. The last carb I ordered through them was superceded many times and you'll sometimes need a new bracket, hose, etc to make the conversion possible.

Craig D Peltier
10-13-2007, 9:36 AM
THanks all good ideas. Not sure about what type of carb I have.
Onto spark plug, it fires fine and runs fine then it starves. So am I correct in thinking sparl plug is fine? When it starts its one pull.
THanks

Greg Peterson
10-13-2007, 2:15 PM
It certainly sounds like it is a fuel starvation issue. As noted above, ensure that any venting in the fuel supply is working correctly and any fuel filters are clear. After verifying that, the carb would be the next item to inspect.

Wes Bischel
10-13-2007, 4:16 PM
My Dad had a problem on his mower years ago. Turned out to be the fuel hose collapsing. I would agree, sounds like fuel starvation.

FWIW,
Wes

Randy Denby
10-13-2007, 6:00 PM
I agree, sounds like fuel starvation....but about the spark plug, they can deteriorate internally to where the wire to the electrode will short when hot due to expansion of the metal. I've had them look good /clean on my dirtbike,but still be bad.Cheap to replace and rule it out.

Bryan Rocker
10-13-2007, 9:24 PM
There are several possibilities. Many of the new B&S engines on lawnmowers have carb's which have very little consumer adjustable parts. There are 2 tubs which extend down into the gas tank. The tubes have fine mesh screens to prevent them from picking up debris. I have seen them where they will allow you to start the engine but after its running a short bit the screen will become clogged with debris, water, or other particles and stall the engines. Once it sits for a few the debris falls off the tubes and you can start it again. There is a diaphragm and spring that sits between the carb and the tank. There should be 2 bolts that hold the carb on and 4 screws that hold the carb down on the tank. If you can remove the carb without damaging the diaphragm you can easily clean off the tubes. Dump out all the old gas. Put a few BB's down in the tank with some WD40 and shake it around to remove most of the debris and dump it out. If the diaphragm is damaged it only costs a few dollars at the local lawn mower repair shop to pick one up. Take the model number and the serial number along with you. Sometimes you can pick up the diaphragm at Wal-Mart of all places. Put it back together and it should run better. I usually do this to my lawnmower before I run it for the first time in the season and occasionally for the HFH mowers I fix.

Bryan

Craig D Peltier
10-13-2007, 10:20 PM
There are several possibilities. Many of the new B&S engines on lawnmowers have carb's which have very little consumer adjustable parts. There are 2 tubs which extend down into the gas tank. The tubes have fine mesh screens to prevent them from picking up debris. I have seen them where they will allow you to start the engine but after its running a short bit the screen will become clogged with debris, water, or other particles and stall the engines. Once it sits for a few the debris falls off the tubes and you can start it again. There is a diaphragm and spring that sits between the carb and the tank. There should be 2 bolts that hold the carb on and 4 screws that hold the carb down on the tank. If you can remove the carb without damaging the diaphragm you can easily clean off the tubes. Dump out all the old gas. Put a few BB's down in the tank with some WD40 and shake it around to remove most of the debris and dump it out. If the diaphragm is damaged it only costs a few dollars at the local lawn mower repair shop to pick one up. Take the model number and the serial number along with you. Sometimes you can pick up the diaphragm at Wal-Mart of all places. Put it back together and it should run better. I usually do this to my lawnmower before I run it for the first time in the season and occasionally for the HFH mowers I fix.

Bryan

Bryan thanks so much. Good info for sure.

Does anyone think that itr could be the auto choke not working properly and shutting down the engine?

Thanks again

David Peacock
10-14-2007, 7:47 PM
I agree with previous poster. Be certain that he hole in the fuel tank cap is not plugged so it vents correctly.

Doyle Alley
10-15-2007, 1:19 PM
I agree with previous poster. Be certain that he hole in the fuel tank cap is not plugged so it vents correctly.

The simple way to test this is to try running it with the fuel cap off. If it still dies, then it isn't a vent issue.

Al Willits
10-15-2007, 1:53 PM
If it runs with the cap off, buy a container of Sea foam, dump about a 1/2 cup in the tank and try ruining it several times, barring some of the less likely causes, gunk in the fuel system is the number one problem these types of seasonal motors have and is the easiest to keep up with, I dump about a 1'4 cup in twice a year at least, I also buy non oxygenated gas when I can, oxygenated gas is bad news for storage, much less efficiency of the motor.

Al

Steven Wilson
10-15-2007, 4:06 PM
x2 on the fuel starvation. I would take out the plug and spray seafoam deep-creep into the cylinder, replace with new plug. Next I would take off and drain the tank then rinse out any gunk in there. Check for any filters and clean them, blow out any fuel pickup lines. Next check and clean out any fuel lines from the tank to the carb. Finally fill gas tank with non-oxy gas and seafoam. I keep a one-gallon gas can with non-oxy gas, stabil, and one can of seafoam mixed in as a base for cleaning out engines (my trolling motor gets it once a month). Then start the motor and run it. If it starts to starve unscrew the gas cap, you may have a venting problem. If that works then there is a breather tube pluged or a bumb gas cap. If not, then start the engine and when it starts to starve spray some deep-creap or starting fluid in the intake. If it picks up then you'll probably have to rebuild the carb (not a bad idea in any case) if not then you may have a compression issue once it's gets warm or some other problem (rebuild time).

Ben Grunow
10-15-2007, 7:31 PM
My craftsman had a vent hole in the gas cap that was clogged and it would stall when running uphill. I drilled a slightly larger hole and the problem is solved.

Are you mowing uphill at the 5 min point?