Lawn Mower Won't Start (eating, good)

[crf450ish]

Originally Posted by gallagheria

I tried using my lawn mower and it would not start. I changed the gas and the oil, and nothing happened. The engine would not start at all. I replaced the spark plug, and it still would not start. I read that if I put some gas behind the spark plug, it might help. I did remove the spark plug and poured in a little gas, and it then did start for a moment. It then shut off. I tried this several times and each time it starts and immediately shuts off--each time after I put more gas behind the spark plug. What does this sound like? Thanks.

You have to take off the cover that covers the flywheel and take some 100 grit sand paper to the square spots on the edge of the flywheel as well as the magneto. These points become rusty due to condensation while the unit is in storage. Look at these pics
http://s.hswstatic.com/gif/chainsaw13.jpg SAND THOSE SQUARE SPOTS

http://0.tqn.com/w/experts/Small-Eng...09/magneto.jpg sand the contact points where the 2 spots nearly come in contact with the flywheel.

[Bulldogdad]

Originally Posted by fisheye

Sometimes, no matter how much you clean your carburetor; you are not going to get the goo out. Sometimes there are diaphragms that start leaking. Not all carburetors are the same or all gum deposits the same.

Many people talk about using products like StaBil to stabilize the gas from season to season. My feeling is that is not necessary or is it necessary to drain and run out all of the fuel. Of course this is my opinion and I am sure some will disagree with me. To me, from being in the business, the worse thing to do is to leave just a small amount of fuel in the tank. That leaves a larger air space and the remaining fuel evaporates and turns to gum quicker. If you top off your tank at the end of the season, I think, you can avoid these problems. StaBil is a great product and I would recommend it to people that plan on leaving equipment sit for years - like snow equipment in areas that only occasionally get snow.

As far as the OP's problem: I think that I would first try a carburetor adjustment (if it has screws to change the adjustment). It sounds as if the motor wants to run. Depending on the make and model; there could be adjusting screws. Here is a link to a B&S help page on carburetors: Adjusting the carburetor. Just be careful adjusting any carburetor because these adjusting screws have tapered points. If you close the screw too tight; you will break off the end of the screw when you attempt to loosen the screw. The reason that I first want to check the adjustment is because sometimes gum or dirt can lodge in the hole that these adjustment screws fit into. Sometimes just readjusting these screws can clear your problem. If you do manage to get the engine going; fresh fuel will help dissolve the gum deposits.

There's ol fisheye.

[Javacoffee]

This is why we have an electric mower that mulches. We plug the cord into an outside outlet and it fires right up. No gas needed. No oil. No spark plugs. Nothing to gunk up or clean. If it doesn't start, we replace the mower. We've had the same electric mower for over ten years. Go electric.

[crf450ish]

Originally Posted by Javacoffee

This is why we have an electric mower that mulches. We plug the cord into an outside outlet and it fires right up. No gas needed. No oil. No spark plugs. Nothing to gunk up or clean. If it doesn't start, we replace the mower. We've had the same electric mower for over ten years. Go electric.

Awww thats so green of you!

[fisheye]

Originally Posted by Javacoffee

This is why we have an electric mower that mulches. We plug the cord into an outside outlet and it fires right up. No gas needed. No oil. No spark plugs. Nothing to gunk up or clean. If it doesn't start, we replace the mower. We've had the same electric mower for over ten years. Go electric.

You would quickly run out of cord on my five acres! Or you would run out of batteries long before you finished. Matching the correct power tool; for the correct job is very important. There is no one mower fits all. If electrics work for you and you don't mind cords; more power to you!

[fisheye]

Originally Posted by crf450ish

You have to take off the cover that covers the flywheel and take some 100 grit sand paper to the square spots on the edge of the flywheel as well as the magneto. These points become rusty due to condensation while the unit is in storage. Look at these pics
http://s.hswstatic.com/gif/chainsaw13.jpg SAND THOSE SQUARE SPOTS

http://0.tqn.com/w/experts/Small-Eng...09/magneto.jpg sand the contact points where the 2 spots nearly come in contact with the flywheel.

I am not saying that you cannot teach one old dog new tricks; but why would you sand the magneto/flywheel areas for a fuel problem or any problem? The OP has spark; they are not getting fuel.

One of the hardest parts of trying to repair any equipment it trying to figure out what the home handyman did before it came to the shop. Customers will tell us that their mowers would start when they put fuel directly into the cylinder and then stop after the fuel ran out. They would fail to tell us what all they did to try to correct their problem. There is a very good chance that they could change settings that would be very costly to fix. There is a good chance that somebody would look at your post and remove the magneto to sand the 'contacts'. If they do; there is a very good chance that they affected the only 'timing' that their motor has - thus also killing the spark. Then the mechanic has to figure out what un-natural catastrophe befell the poor mower!

I don't mean to pick on you. I do like the idea of saving people money. Just be careful what you recommend.

[crf450ish]

Originally Posted by fisheye

I am not saying that you cannot teach one old dog new tricks; but why would you sand the magneto/flywheel areas for a fuel problem or any problem? The OP has spark; they are not getting fuel.

One of the hardest parts of trying to repair any equipment it trying to figure out what the home handyman did before it came to the shop. Customers will tell us that their mowers would start when they put fuel directly into the cylinder and then stop after the fuel ran out. They would fail to tell us what all they did to try to correct their problem. There is a very good chance that they could change settings that would be very costly to fix. There is a good chance that somebody would look at your post and remove the magneto to sand the 'contacts'. If they do; there is a very good chance that they affected the only 'timing' that their motor has - thus also killing the spark. Then the mechanic has to figure out what un-natural catastrophe befell the poor mower!

I don't mean to pick on you. I do like the idea of saving people money. Just be careful what you recommend.

Dude i guess its over your head. You can't affect the timing on a single cylinder lawnmower engine. The magneto only comes off one way and goes back on one way. Its not like an old school distributor style ignition on a V8 where the slightest movement of the distributor will affect timing. Whatever though, aint my mower, not my problem...not going to defend myself any further, how one interprets what I say is their deal!

[Javacoffee]

Originally Posted by fisheye

You would quickly run out of cord on my five acres! Or you would run out of batteries long before you finished. Matching the correct power tool; for the correct job is very important. There is no one mower fits all. If electrics work for you and you don't mind cords; more power to you!

True. Electric isn't for everybody. I hate cords, but I hate gas mowers that won't start even worse. I had a battery-start gas mower once, and I still could never get it started. Hate 'em all.

[Hemlock140]

Originally Posted by Javacoffee

True. Electric isn't for everybody. I hate cords, but I hate gas mowers that won't start even worse. I had a battery-start gas mower once, and I still could never get it started. Hate 'em all.

I won't invite you over to help me in the yard, then. I have a push mower, a riding mower, chipper/shredder and rototiller, chainsaw and generator, all gas powered. I run them all dry the last time I use them for the season and haven't had a problem since I forgot to do that years ago on my (gas) outboard motor.

[fisheye]

Originally Posted by crf450ish

Dude i guess its over your head. You can't affect the timing on a single cylinder lawnmower engine. The magneto only comes off one way and goes back on one way. Its not like an old school distributor style ignition on a V8 where the slightest movement of the distributor will affect timing. Whatever though, aint my mower, not my problem...not going to defend myself any further, how one interprets what I say is their deal!

OK, I have been out of that business for years and I should have said air gap and not 'timing'. But it still is about the fact that the OP has a fuel problem and not spark problems. I just worry that many will look in the wrong place and cause other problems. I want to keep them focused in the right direction.