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: Getting gas and spark, still not starting

12-29-2009, 09:13 AM
Hi, my JD LX172 is getting gas and a spark but still will not start. A new spark plug, new gas, and a cleaned up carb didn't help. It cranks but will only backfire. The last time it ran was in September. Any suggestions would be greatly appreciated! Thanks

12-29-2009, 09:28 AM
Pull the plugs, and drip a little fuel directly into the spark plug hole. Reinstall the spark plug, and try to start it then. If that doesn't start it, then you have an electrical/spark or air issue.

Assuming you didn't mess with engine timing somehow then it should start right up. How are you confirming that you are getting fuel and spark?

Remember it takes the following to make an engine run:

Walt 2002
12-29-2009, 09:29 AM
"Any suggestions would be greatly appreciated! Thanks"

Post what ENGINE you are talking about.

Walt Conner

12-29-2009, 09:56 AM
The engine is a 14 hp Kawasaki. The plug is wet after cranking it. When holding the plug next to a screw, a spark is present. I tried a little starting fluid in the plug hole, and received a nice backfire.

12-29-2009, 10:10 AM
Sounds like it is flooding it out.

12-29-2009, 10:29 AM
try tapping on the bowl with a wrench, float could be stuck.
Then open the trottle wide open, with choke open, and crank it over.

12-29-2009, 10:35 AM
Remove the plug and verify that it actually has compression.

12-29-2009, 10:39 AM
An engine won't create vaccuum to suck the gas in, without comression.

12-29-2009, 10:51 AM
How old is the gas?
Will it burn on the driveway?
Gas does go bad......

12-29-2009, 10:53 AM
An engine won't create vaccuum to suck the gas in, without comression.

It will create enough to suck fuel, just not compress it enough to fire. However, since the engine is backfiring, he's probably got sufficient enough compression.
I've had some engines (Honda motorcycles) where the plugs couldn't be simply dried off after flooding, but rather had to be replaced. OP said he did replace the plug, so we can rule that out. I second the flooding out due to carb issue, or possibly "weak spark" i.e. from bad connection, weak coil, or decroded plug wire. Whatever it is, it's probably going to be a simple solution. Finding the problem is the hard part.

12-29-2009, 11:00 AM
It is likely flooding. Is the choke lever on the carb stuck open? However, backfiring is typically a sign that the engine timing is off, or your plug wires are routed improperly from the Distributor to the spark plug.

I assume you are getting sufficient air, so it has to be a fuel issue or the weak spark, condensor, coil, etc.

12-29-2009, 11:16 AM
If the engine is backfiring, it has spark, compression, fuel, and air so my guess would be the timing. I would check the flywheel key.

Herd of Deeres
12-29-2009, 12:02 PM
The 14HP Kawasaki FC 420V has an odd electrical connector that attaches to the carb float bowl on my 175. Since mine fired right up with fresh gas after 2+ years in a barn I never bothered to find out what it does.

12-29-2009, 12:27 PM
If the engine is backfiring, it has spark, compression, fuel, and air so my guess would be the timing. I would check the flywheel key.

Yup sounds like timing is off.

12-29-2009, 12:42 PM
If you can shut the fuel off all together, that is make sure the engine will get no fuel what so ever, Remove the plug and crank it over several times to clean out the cylinder. Get a fresh plug. I can't tell you how many times I have seen a plug get wet and fire outside of the cylinder, but not fire under compression. Install new plug, and try to start with starting fluid. Don't overdo it on the starting fluid, it can be hard on an engine if used too much. Being that it is a gas instead of liquid you can eliminate the fouling. See if it will fire on the starting fluid. If it does you have a flooding problem. If it backfires on the fluid then you have a timing problem. If it will start or attempt too, then you know its flooding itself. I have had several engines that were stored, where the float was sticking and flooding, therefore fouling the plug causing backfires. I always change out a plug that has gotten excessively "wet" with fuel. Plugs don't last like they used too.

Tony bachler
12-29-2009, 09:04 PM
I have it happen to me many times,, In the repair shop the plug will Be wet and fire When it take it out And short it ; Put it back in And nothing;. NOW for the facts in our shop; The champion plug will do that, Throw it in the dumpster, Put a new out of the box it the engine. we use BOUSCH or NGK. they have worked for us; Put a new plug in every year ;They cost less then $5.00 bucks. That's cheap maintainance, I say.

12-30-2009, 12:34 PM
You may have water in your fuel tank,or fuel storage can.....a bad sparkplug.a stuck valve ,or low compression bet is h2O...Jim

03-28-2010, 09:52 PM
I was wondering if you had found out the problem??? Mine is doing the same. It ran fine I parked it for 3 weeks went to start and had this problem . I drained the tank, cleaned fly wheel, cleaned coil. checked for a stuck valve...I can get mine running sometimes but then will bog down and back fire and stahl. or it just will crank but just back fire. I took the carb off today. I'm going to rebuild it. Let me Know Thanks

03-29-2010, 01:53 AM
Double check all your wiring, I once had a mouse or other vermin chew through a wire on a fuel pump on my Jeep. I think they like the flavor of plastic or PVC wire insulation, who knows.

03-29-2010, 09:20 AM
Does it back fire, or out through the exhaust?
I agree on the timing. 99% of starting problems are ignition related.
Do a full service on the ignition, and reset the timing.