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..

 

[Midniteoyl]

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..

Telling ya,, had the same thing. Run for 10-20 secs then shut down. Cleaned carb twice, then bought coil and plug. Only the plug was needed. Then the other mower did the same thing... Then, my brother called and said Mazda dealer wanted $900+ to replace a coil that was 'missing' according to codes (he had a bad idle miss). Told him to change plugs. Code (miss) is gone.

 

[Soundguy]

not counting fouled plugs. plugs have to be the most trouble free part of ignitions setups i've ever found.. if you count in wear from electrode erosion.. that bumps capacitors up tot he most reliable.

must be some darn junky plugs being made today...

 

[Panzer315]

This has got me baffled. My JD rider has a PA540A engine in it. It starts very quickly, but then dies after 20 seconds of full throttle running. If I start it then quickly throttle back, it will run for 30 seconds. The fuel tank is not creating a vacuum, because the same symptoms apply if I leave the gas cap off. The fuel shutoff solenoid on the carb is opening, and the float is allowing fuel to flow quite well without the engine running, even through the fuel pump. All the fuel pump baffles/ bellows seem intact and flexing. Nothing seems gummed up in there.

It seems fuel starved to me. Perhaps a fuel line collapsing? I tried dripping gas into the throat of the carb at low speed. It backfired a bit, but still died at the same time (30 seconds)

I have not changed the plug. It just seems too consistent to be the plug heating up and then going bad at the same time, every time.

Replace the fuel lines first (all 5 feet of them)?
Spark plug first?
Remove & thoroughly clean the carb?

Thanks in advance.
Bret

Njnusxkjoloplnguyvaqw........7!$&&&&9&:83&$&&&93&
B. n. n. b. b. b. b. b. n.

From iPhone To Tractor-By-Net

 

[Gale Hawkins]

Spark plugs can really do strange things I guess. Glad you got it running and the grass cut.

 

[JazzDad]

Now that I think of it, maybe 22 years on the same plug was a little too much to expect. :confused3:

 

[Gale Hawkins]

While that may be the fact that it would die after 20 seconds over and over is plain STRANGE. Never hear of that in all my years.

Knew of a guy that worked in a car factory like 50 years ago and his car would die at the same location going to work each day. We are talking low tech car era. Turned out to be a lot of trash in the tank and it would get sucked over the pick up in same amount of miles each day. When it would die the trash would drop back down so it would restart.

Machines can be a mystery.

 

[Soundguy]

20ys on the same plug. i'm surprised it had any electrode left..

 

[Midniteoyl]

Depends on use. The one in my Honda push mower I just changed after 15 years..

 

[Soundguy]

well..i guess if it only gets used 5hrs a year.. then yeah..

 

[MoKelly]

This is very interesting. In all my years and troubles with small engines, a new spark plug has never ever never been the answer to a starting or running problem.

Glad it all worked out.

MoKelly