Lawn mower help needed

Squirt some gas right into the carburetor, open the throttle all the way and crank it. If it pops and runs a second, you have a fuel/carb problem.

You mean starter fluid here, right?

Why? Wasn't running well?

You don't mention the sparkplugs. Gap? Fouled? I wouldn't expect both to foul at once, but maybe you were only running on one cylinder for a while and then the second one went.

Check to make sure the push-rods haven't worn down or the tips broken off. I've seen this on more than one Briggs and Stratton motor.

At church, the nice sunday school teacher was asking the class to give the name of some thing. It's brown, runs up trees, and eats nuts from the nut trees. The class is silent. Finally a boy raises hand, and is recognized. "I know the answer is Jesus, but it sure sounds like a squirrel, to me."

In this case, I trust you didn't hit a rock or some thing. But it sure sounds like a sheared flywheel key, to me.

There's only fuel, fire and timing. You've got the first two, and if it was timing you'd get at least a backfire.

My guess? You have a bad safety switch, probably under the seat.

Safety switches work by shorting or disconnecting the ignition. He has spa rk so it's not a safety switch.

Confirm you have spark on both cylinders. Your compression numbers are ok. It will be a bit higher when it's actually running. Spray ether down the carb, not on the filter. If it doesn't try to start then you should check for a sheared key. If it does try to start you still have a carb problem.

No spark if the safety switch(es) bad - so your guess is an uneducated guess - and is wrong. One other thing you forgot that is required foran engine to run - "squeeze" or compression - 110 isn't bad - 80 is a bit low. Try putting in 2 brand new plugs of the recommended type.

You're the second one to mention a sheared key. How would that cause this problem?

On points ignitions, if the flywheel is turned, you lose spark. On electronic magnetos, the spark happens at the wrong time in the compression cycle. So, on some motors it is possible to have spark. But, spark at the wrong time.

Thanks all, here is what happened. Got starter fluid and it immediately started. Stopped engine and it started fine without the fluid. Mowed for about 30 minutes and then started to lose power. Got to the point where the engine would die if I engaged the mower deck. Another clue: If I reduce the speed to idle (idles beautifully) and then slam it on to full throttle it literally takes almost 30 seconds before top speed is reached. Makes me think that the fuel delivery cannot keep up with the demand.

Any easy way to check fuel pump delivery? If I hold a gas container overhead (gravity feed) and the problem goes away, can I suspect the pump?

Thank you, Ivan Vegvary

Oh, yeah, the key is under the flywheel/magneto thingy. I had in mind that it was under the blade!!

Most engines I've seen, the key is at the center of the flywheel, where the flywheel meets the crank shaft.

Two possible problems to keep in mind:

Bad motor oil (more a problem on Tecumseh walk behind mowers).

Valve clearance.

Any easy way to check fuel pump delivery? If I hold a gas container overhead (gravity feed) and the problem goes away, can I suspect the pump?

YES!!!!

Have you checked the vent in the cap??? Is there a fuel filter? Has it been checked/replaced?

Put a pressure guage on the outlet of the pump to check pressure. Connect your "gravity feed" tank to the carb and check delivery of fuel from the fuel tank/pump.

...seriously, what kind of drugs are you on?

It would change the ignition timing - but virtually unheard of in anything other than a vertical shaft single cyl direct drive rotary mower.

This machine is neithe a direct drive nor a single cyl, and is most likely NOT a vertical shaft engine (although it COULD be).

Ivan Vegvary posted for all of us...

No fuel pump. gravity feed.

On some there is a key there too.