Mower starts then quits...then starts and runs fine?

[crazyjoe]

I have a Toro Recycler lawnmower, about 2 and a half years old. In other words, just outside of their "guaranteed to start on the first pull" warranty.

The mower is one with a priming bulb, you push it threee times, then yank, and it is supposed to start. And it does, sort of, it kicks over and fires for about 1 second, then dies. A second priming and pulling, and it always starts.

What is the most likely culprit for this behavior? Spark plug? Air filter? Something worse?

[Finagle]

Fuel filter or dirty carburetor would be my guess. Although IC engines can be tricky -- on my Honda mower, it's a weak spring on the choke that's been causing starting problems.

[Baracus]

Have you tried pushing the bulb a couple extra times? In addition to what Finagle said, perhaps the bulb is cracked/leaky and not drawing enough fuel in on the first three pumps.

[Eureka]

My guess is that there is a loose electrical connection somewhere.

However, this guess is based on similar symptoms happening with my car--it became scary to drive, because it generally stopped running while I was halfway out of a parking space, but did not generally cause me problems otherwise.

(For clarity's sake, here's the timeline--oil change Wed, left town Thurs, Job interview and drove back to town Fri, took car to dealer for fixing Sat.)

ETA: after rereading OP--when my car was acting up, as described above, it would in fact appear to start normally, it just would quit half a parking space later.

[Gary T]

Pump the priming bulb 5 or 6 times and I'll bet it starts and stays running. It's not brand spanking new anymore. With some carbon build-up here and there, starting and running cold may require a little more gas than it used to.

[johnpost]

i would agree that a couple more priming bulb pushs would seem to be good.

if in two years you haven't cleaned the spark plug that could be a factor in starting.

[gotpasswords]

Originally Posted by Gary T

Pump the priming bulb 5 or 6 times and I'll bet it starts and stays running. It's not brand spanking new anymore. With some carbon build-up here and there, starting and running cold may require a little more gas than it used to.

You've described my four year old mower perfectly.

So, how can we get the carbon out? Will a steady diet of name-brand gas such as Chevron or Shell help? Give it a slug of Techron now and then? Or, is this something that needs taking the cylinder head off and scraping it out?

I give the mower annual plug, air filter and oil changes, and run it dry at the end of mowing season. Despite this, it's a cantankerous cuss to start every week. If the gas tank is less than half full, it's almost guaranteed to be a non-starter. Believe it's a 4 or 4.5 HP Briggs engine.

OTOH, my generator is six years old and is a reliable one-pull starter, again with nothing more than an annual plug, filter and oil change. 10 HP Briggs engine on this one.

[crazyjoe]

I guess I should have mentioend that lately I have taken to priming the bulb more times, with the same result. Starts, dies, then starts and runs for a full lawn-mowing job with no apparent difficulties.

[gonzomax]

Change the plug.

[Runs With Scissors]

Is it a Briggs and Stratton (Or is it Meyers Briggs...) engine?

Home Despot sells tune up kits: new engine oil, air filter, spark plug, gasoline conditioner.

When was the last time you changed the oil? Had the blade sharpened?

[Magiver]

Sounds a little lean on start up. Prime it 3-4 times max and let it sit for 10 seconds for the gas to evaporate. I prime mine in the garage and then start it outside. Start it at idle and let it warm up for another 10 seconds. It's a friggin air cooled engine, be nice to it. No engine should be started and then run at full output at the git-go. If you over prime it you’ll get a plume of black smoke and that just means you soaked the spark plug and that doesn’t help anything. You’re goal is to prime it just the right amount for start.

Your choke system could be set a little lean or the plug may need some love. Pull the plug and see if it looks clean without any deposits and the gap is where it should be. If the air cleaner is dirty it will actually run rich because it's not pulling air in relation to the atmospheric pressure of the carburetor bowl. After that you should make sure all the linkages are moving freely so the choke and/or speed regular is not binding.

[Olentzero]

If all else fails, have a young British accounts manager stand in the immediate vicinity.

[gotpasswords]

Originally Posted by Olentzero

If all else fails, have a young British accounts manager stand in the immediate vicinity.

Why? Are you trying to channel the spirit of Lucas Electric?

Meanwhile, I still want to know why my mower's being a pain with a new air filter and spark plug.

[Dallas Jones]

Does it have an automatic choke or do you manually move a lever? It sounds like it needs a little less choke than it is getting. A dirty air filter could cause this. Sounds like you have changed the air filter. If it has one of those foam covers on the air cleaner, wash it and let it dry.

It sounds like it starts the first time, gets choked out, then when you start it the second time the choke setting has opened up and it runs fine. Or it might not be getting enough choke when you first try it.

BTW, the priming bulb only circulates fresh gas through the carburator. It does not spray any gas into the throat of the carburator, like pumping the gas in an old car. So even if you push it 10 times it will not give the spark plug any gas. The choke setting pulls the initial gas in. So I think it is either over or under choked at start up.

Particularly if it runs fine after you do get it started.

[Magiver]

Originally Posted by gotpasswords

Meanwhile, I still want to know why my mower's being a pain with a new air filter and spark plug.

It's a process of elimination. You've eliminated dirty air cleaner and fouled plug. If it runs fine once it's warmed up then that suggests it's is running slightly lean. Here is a good video dealing with an automatic choke. It shows the problems of varnished gas clogging the pickup tube and how to adjust the mixture screw.

[Magiver]

Lots of video's on youtube so it's a matter of finding one with your type of carburetor.
Plastic Carb
Toro Super Pro Recycler II lawn mower

Some are self choking and will be hard to start after they run for awhile because the are pulled open after start (and will close after the engine stops). Others have a choke setting in the cable.

[Olentzero]

Originally Posted by gotpasswords

Why? Are you trying to channel the spirit of Lucas Electric?

No, sorry... Mad Men reference. Couldn't resist.

[crazyjoe]

Thanks to everyone...I change the oil once a year, but I have not replaced the air filter (I think). It's a pleated paper filter. I do occasionally take it apart and rap it on the cement to get big clumps out.

[billfish678]

Originally Posted by Magiver

It's a process of elimination. You've eliminated dirty air cleaner and fouled plug. If it runs fine once it's warmed up then that suggests it's is running slightly lean. Here is a good video dealing with an automatic choke. It shows the problems of varnished gas clogging the pickup tube and how to adjust the mixture screw.

Thats why I add gas stabilizer to my mower gas on a regular basis.

My neighbor had a similiar problem. I told him to add LARGE quanties of gas stabilizer to his mower every time he used it. The stuff slowly and safely dissolved those deposits and now his mower runs fine.

[butler1850]

For a "regular maintenance" cleanout, I use SeaFoam in all of my small engine gasoline cans. Works on 4 cycle engines, and on 2 stroke oil-gas mixtures as well.

It combines the merits of a stabilizing product like Stabil, and a fuel system cleaner like Techron in one application.

Heavier concentrations to clean, lower to maintain.

[billfish678]

Originally Posted by butler1850

For a "regular maintenance" cleanout, I use SeaFoam in all of my small engine gasoline cans. Works on 4 cycle engines, and on 2 stroke oil-gas mixtures as well.

It combines the merits of a stabilizing product like Stabil, and a fuel system cleaner like Techron in one application.

Heavier concentrations to clean, lower to maintain.

Forgot about that stuff, it works great as decarbonizer as well as fuel stabilizer in my experience as well. Only really needed something that good for our 4hp outboard boat motor.

Only NAPA? DAPA? auto stores seem to carry it though. Good stuff on the net for how to use it as well.