Engine runs 20 seconds, then quits

[JerryK]

It could be blocked airflow... which means intake AND exaust. [ someone stick a potato(e) up your kiester..?? ] Semi blocked fuel line/filter will do it... lets enough gas thru slowly to run until you use that portion up...then you have to wait until the line gets more fuel in it. Flywheel electronic module will heat up and do that sometimes if it is bad.....

 

[jinman]

I'm a bit slow with just the engine number, but now I realize it is a Kawasaki engine. The carburetor and fuel pump work similar to the Briggs & Stratton and can be checked with the same air pressure on the fuel inlet. The valve is probably about twice as expensive though at around $20.

If it dies and won't start, but will try to start if you pour a little gas down the intake, it's a fuel feed problem, pure and simple.

 

[bh3zfc]

Are you running ethanol fuel? Try a bottle of seafoam. Most mechanics will put seafoam in your vehicle/tractor/4wheeler or whatever and then charge you a outrageous price for something they made up that was causing the problem.

 

[BBO]

Are you running ethanol fuel? Try a bottle of seafoam. Most mechanics will put seafoam in your vehicle/tractor/4wheeler or whatever and then charge you a outrageous price for something they made up that was causing the problem.

The Seafoam deal is true. I have heard that this stuff will smooth out engine problems after one tank. Not sure they use a whole bottle.
I use in to treat and clean Diesel fuel tanks that have been sitting with old fuel.

I have learned to replace fuel lines if you suspect trash problems. Especially the line from the filter to the carb.
I have found where small pieces of fuel line clogged up the needle/jet. This is related to Ethanol and age of the lines.

When it stops pull the plugs out to see if they are wet with fuel.

It's not that expensive to replace the line all the way from the tank to the carb.

 

[JazzDad]

I'm sure you've been waiting with intense anticipation for the outcome of this saga. Well, wait no more.

I have to admit here, that I did not adhere to Jim's troubleshooting method. (It takes a great effort to pull my compressor from the barn and haul it over to the equipment shed. That said, I thought long and hard again about the symptoms. It had to be fuel starvation! It would run 27 seconds at full throttle, and about 33 seconds at an idle. Not knowing the rate of fuel consumption, I convinced myself that this must be the amount of fuel in the bowl, and that it was not being replenished by a sticking needle valve. I bought the valve ($18), and a little O-ring ($1) that I may have messed up with my multiple dis-assembly/ assembly activities.

I put it all back together and it started right up (as normal). It ran for 27 seconds and died (as the new normal). I could see there was fuel in the filter. I tried to re-start it immediately and there was a tremendous backfire from the exhaust. I was glad there was nothing flammable nearby, and my hearing came back within a few minutes. This told me there was too much fuel, and not enough spark?
Out of shear desperation now I installed the $2 spark plug I had previously bought. (I didn't install it before this time as the symptoms did not fit.) The mower started right up (as normal). I realized I had counted to 53 seconds when my brain said, 'hey, dummy. That's longer than before.' 2 hours, and the side and front yard later, I put it away in the shed.

I don't know why I make my life more complicated than it really has to be. Yet another reminder to always try the simplest, and least expensive, things first. GreenRules and Midniteoyl rule this thread. Thanks to everyone's assistance!

 

[Midniteoyl]

Ahem..


Glad you got it fixed!


Had 2 lawn mowers AND my brothers Mazda CX7 do the exact same thing recently.

 

[Kyle_in_Tex]

Just saw this and glad you got it fixed. It can sometimes be the spark, but where in the system is the heat/load causing the problem? Sometimes it's the plug, others it's the coil, and old school stuff has capacitors that can be the culprit.
Haven't heard from you in a while, how's everything going?

 

[jinman]

Well, if you can't get a compressor handy, then there is the fuel down the carb inlet test. Either is checking fuel starvation. The important thing is that you stuck with it anf found the problem. I'm a little surprised that a spark plug failed with those symptoms. Interesting problem. . .

 

[BBO]

. I'm a little surprised that a spark plug failed with those symptoms. Interesting problem. . .

I wonder if Jazzdad may also have a coil problem also. I have hear of coils shutting down with heat, and somewhat hard to troubleshoot.
Often it's the wire vs. the coil.
I would keep a close eye on that side. You can tell lots by looking at how the plugs are firing by removal.

 

[Soundguy]

. I'm a little surprised that a spark plug failed with those symptoms. Interesting problem. . .

I agree. a timed spark plug failure?

almost had to be a cracked insulator that heated up fast and let spark short thru at a very small place/gap.. etc..