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I have a Lazer Z with the Kawasaki FX730 motor. It was surging and stalling frequently. Would run choked even with PTO engaged but eventually die.
I replaced the easy stuff (fuel pump, filter, air filter) and then changed the oil and oil filter. Still having problems so I tested the spark plugs, they were both sparking but one of the coils was reading a short.
Replaced both ignition coils and carburetor.

Now, it’ll turn over but not start. It’s low on fuel but there’s enough that it should start. All connections (electrical, mechanical and fuel lines) are as they should be. I’m scratching my head…

Any suggestions?

Kawasaki OEM Parts?

mechanic mark said:

Kawasaki OEM Parts?

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Yes, from dealer

Have you tried putting a small amount of fuel into the intake and trying to start it. If it starts and then dies then you have a fuel delivery issue which could be something as simple as the fuel solenoid on the bottom of the carb not working. If it doesn't start then maybe look more into the igntion spark issue

ILENGINE said:

Have you tried putting a small amount of fuel into the intake and trying to start it. If it starts and then dies then you have a fuel delivery issue which could be something as simple as the fuel solenoid on the bottom of the carb not working. If it doesn't start then maybe look more into the igntion spark issue

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I sprayed starter in the intake and still nothing. Will try changing the plugs but I am getting a spark at both with a tester attached.

Well I changed the plugs and it started. Ran at pretty low rpm for a few minutes and would die when driving forward. Did that twice and then started running normally third time. It’s raining here so can’t run her for a few days so will see…

Well it was running great, better than ever actually. I mowed for 20 mins and then stopped to talk to my wife. Killed the engine while we talked and the. Got back on 5 mins later. Now it won’t start?!?!

Sounds cold blooded. Did you choke it for the restart ?

Check the timing key

7394 said:

Sounds cold blooded. Did you choke it for the restart ?

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Yes

bertsmobile1 said:

Check the timing key

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I’m not sure how to do this?

Remove the finger guard over the flywheel & remove the nut / bolt that retains the flywheel.
You will see a square hole that is 1/2 in the flywheel & 1/2 in the crankshaft
The 2 sides must come together to make a perfect square if not then the flywheel has slipped on the crankshaft & the spark is happening at the wrong time
It only has to be a few thou out & the engine will run fine WFO but be near impossible to start

When you turn the key to ON, you should hear a faint 'click' from the front of the engine beneath the Float Bowl.
It is the Fuel Shut Off Solenoid opening. If you don't hear that, check further. There is a multi wire connection under the 'dash' near the Ignition switch. Sometimes there is a disconnect there. Undo the connector and inspect then spray with Electrical contact cleaner. Listen again for the click. If you don't hear it, it won't start.
If it does not fire when spraying Quick Start directly into the carb while cranking, it is an electrical problem. If it starts and then shuts off it is a Fuel problem. Did you replace the Fuel Pump? Try taking a deep breath and blowing into the Fuel Tank, hold pressure as long as you can. Replace Fuel Filter.

Jimmac said:

I have a Lazer Z with the Kawasaki FX730 motor. It was surging and stalling frequently. Would run choked even with PTO engaged but eventually die.
I replaced the easy stuff (fuel pump, filter, air filter) and then changed the oil and oil filter. Still having problems so I tested the spark plugs, they were both sparking but one of the coils was reading a short.
Replaced both ignition coils and carburetor.

Now, it’ll turn over but not start. It’s low on fuel but there’s enough that it should start. All connections (electrical, mechanical and fuel lines) are as they should be. I’m scratching my head…

Any suggestions?

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Did you adequately space the coil faces from the flywheel or just eyeball it?

RevB said:

Did you adequately space the coil faces from the flywheel or just eyeball it?

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Used a business card as a spacer.

Also the solenoid is new, it clicks.

Someone said that if it struggled to turn over after it was ran, it could be gas getting into the oil? I plan to check the timing as suggested above.

Jimmac said:

Used a business card as a spacer.

Also the solenoid is new, it clicks.

Someone said that if it struggled to turn over after it was ran, it could be gas getting into the oil? I plan to check the timing as suggested above.

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Gas in oil is highly unlikely.
Your timing should be fixed but the coil to face is slightly variable. Make sure there is no rubbing of the flywheel against the coils. It'll still run but not the way the parts should be set up. Business card is a good approximation.

RevB said:

Gas in oil is highly unlikely.
Your timing should be fixed but the coil to face is slightly variable. Make sure there is no rubbing of the flywheel against the coils. It'll still run but not the way the parts should be set up. Business card is a good approximation.

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Also, my 730 water cooled likes choke when cold and no choke when warm. Just depends on the degree of "warmness".
Also had a problem with the original Kawasaki coil wires....they are carbon track "wires" meaning that there is a carbon impregnated string that forms the current carrying member of the cable. In my case the engine, for some time before failure, would have much reduced power and finally just quit firing on one side. The coil itself is fine it's just the cable. After OHMing out the cable and finding it was an open circuit, cut off the plug boot and found that the cable didn't have any string in the center and the carbon just fell out of the hole. Probed and cut the cable back a bit and found the string was there....manufacturing defect. There was enough cable left to attach the boot imaged below, which just screws on to the cable. Now, I'm not saying this is your problem but bad, new parts are known to occur rarely. And some old seemingly reliable parts just quit working. And, no...this is not my favorite failure as some folks seem to have....you just have to follow the clues to your resolution.

Keyways seem to be other's favorite.....unless you whacked something really hard it takes a ton of force to make a key fail.

NGK (8328) LB01EP Spark Plug Cap , Black​

RevB said:

Gas in oil is highly unlikely.
Your timing should be fixed but the coil to face is slightly variable. Make sure there is no rubbing of the flywheel against the coils. It'll still run but not the way the parts should be set up. Business card is a good approximation.

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When you say "struggled" are you referring to cranking or just once started, running.

RevB said:

When you say "struggled" are you referring to cranking or just once started, running.

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Struggled to start.

BUT… good news. Went to check the battery before checking the timing today and noticed the fuel filter was cracked where the “spout” meets the main barrel. Battery was fine, so I changed the fuel filter and mowed about 2 acres with no issues. Even stopped a couple times and restarted fine hopefully it was just the filter!

You should also check your Valve Lash while you are into it. Get new gaskets first.
Glad you are rotating again!

Jimmac said:

Struggled to start.

BUT… good news. Went to check the battery before checking the timing today and noticed the fuel filter was cracked where the “spout” meets the main barrel. Battery was fine, so I changed the fuel filter and mowed about 2 acres with no issues. Even stopped a couple times and restarted fine hopefully it was just the filter!

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Jimmac said:

Struggled to start.

BUT… good news. Went to check the battery before checking the timing today and noticed the fuel filter was cracked where the “spout” meets the main barrel. Battery was fine, so I changed the fuel filter and mowed about 2 acres with no issues. Even stopped a couple times and restarted fine hopefully it was just the filter!

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New, defective parts. Good on ya for finding the problem.

It takes a long time to learn to check the simple things first. Glad you are up and running.

Jimmac said:

Struggled to start.

BUT… good news. Went to check the battery before checking the timing today and noticed the fuel filter was cracked where the “spout” meets the main barrel. Battery was fine, so I changed the fuel filter and mowed about 2 acres with no issues. Even stopped a couple times and restarted fine hopefully it was just the filter I asked about the "struggle to start"

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Reason I asked about the "struggle to start" issue is because most of the starters on small engines look like they're well sealed but are not. Because of the dusty, litter ridden environment material always seems to work it's way into the case and the dirt will cause the starter to slow down and present itself as a problem masquerading as other similar issues. Doesn't take much dirt to lock up a Bendix. Just something to keep in the back of your mind for future reference.

Ok so this damned thing is down again.

Started first time today then died. Got it started again and mowed a little. Started surging so I looked around and could see the governor bobbing up and down. Adjusted the throttle down an little and stabilized it. Ran for another few minutes and stopped. Now it won’t start. Voltage is showing 12.7V on the panel.
I’m turning the key, it’ll try to turn over a few times then dies. It does this choke on or off.

As I’m typing this, I got it started again. Will check back in a few.

Jimmac said:

Ok so this damned thing is down again.

Started first time today then died. Got it started again and mowed a little. Started surging so I looked around and could see the governor bobbing up and down. Adjusted the throttle down an little and stabilized it. Ran for another few minutes and stopped. Now it won’t start. Voltage is showing 12.7V on the panel.
I’m turning the key, it’ll try to turn over a few times then dies. It does this choke on or off.

As I’m typing this, I got it started again. Will check back in a few.

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Mowed another acre or so with no issues. Throttle pulled back from max just a touch. Do you all think it’s just the governor high idle screw adjustment?

Not sure of your model. Some Throttles actuate the Choke as well and you may have been doing that.
Look at the simple things first. Fuel, Fuel Filter, tight carb to manifold bolts etc.

Gord Baker said:

Not sure of your model. Some Throttles actuate the Choke as well and you may have been doing that.
Look at the simple things first. Fuel, Fuel Filter, tight carb to manifold bolts etc.

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Kawa FX730V. Thanks I’ll check the bolts on the carb.
I ran it another 1.5hrs with the idle screw adjusted and it ran the entire time. It did struggle to start when I stopped half way through.
When it doesn’t start, what happens is; I turn the key, it makes a noise like it’s about to turn over but stops. I try again and again and it starts to turn over. Then it continually turns over without starting and eventually start.
I checked and am getting spark.

You should get new gaskets and then check valve lash. Check your Manual for settings. Time for new spark plugs? Have you checked the Flywheel/Crankshaft key to be sure it hasn't partially sheared?

Gord Baker said:

You should get new gaskets and then check valve lash. Check your Manual for settings. Time for new spark plugs? Have you checked the Flywheel/Crankshaft key to be sure it hasn't partially sheared?

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It has new plugs and coils. New head gaskets?

Post #28 tells me you have a bad or loose connection in your starting circuit. Check to see if all connections are good and clean, plus tight. As the ground connection is through the starter housing, make sure that the starter is not loose.

New Valve Cover gaskets in case you need them after setting Valve Lash (clearance). Removing the Engine fan assembly will let you see if the Crankshaft key is partially sheared. It could also be dirt floating around in the carb. Simple things first! Have you drained the Float bowl?

Valve lash is .004 to .006 both valves

Gord Baker said:

New Valve Cover gaskets in case you need them after setting Valve Lash (clearance). Removing the Engine fan assembly will let you see if the Crankshaft key is partially sheared. It could also be dirt floating around in the carb. Simple things first! Have you drained the Float bowl?

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It’s a brand new carb

Have you checked to see if you have stuff floating around in the tank. That could stop up the pick up tube in the tank.

hlw49 said:

Have you checked to see if you have stuff floating around in the tank. That could stop up the pick up tube in the tank.

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Nothing in the filter other than fuel and flows freely

Please keep this thread going. I have the exact same issues except mine never runs over about 10 mins. Mine is a BADBOY but same Kawasaki 731 engine?
Been struggling all year.
Very disappointed in the Kawasaki. Has less than 50 hours!

Hardluck said:

Please keep this thread going. I have the exact same issues except mine never runs over about 10 mins. Mine is a BADBOY but same Kawasaki 731 engine?
Been struggling all year.
Very disappointed in the Kawasaki. Has less than 50 hours!

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I have a mechanic coming Wednesday to look at it. Mine has 1,000 hours

Keep posting please .

Hardluck said:

Please keep this thread going. I have the exact same issues except mine never runs over about 10 mins. Mine is a BADBOY but same Kawasaki 731 engine?
Been struggling all year.
Very disappointed in the Kawasaki. Has less than 50 hours!

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Back in the day, this would indicate a failing Coil due to heat.

Could be but unlikely both coils would go at the same time. Could be a fuel tank not venting. Could be restriction in the fuel supply. Have diagnose the problem. When is stops try spraying gumout carb cleaner in the carb. If it starts fuel problem if not ignition problem. Then try unpluging the ignition kill wire to make sure it is not in the mower. There where the starter is there two wires that plug in to the engine wiring. One is green fuel solenoid the other is black ignition kill wire, unplug the black wire and test for fire again.

hlw49 said:

Could be but unlikely both coils would go at the same time. Could be a fuel tank not venting. Could be restriction in the fuel supply. Have diagnose the problem. When is stops try spraying gumout carb cleaner in the carb. If it starts fuel problem if not ignition problem. Then try unpluging the ignition kill wire to make sure it is not in the mower. There where the starter is there two wires that plug in to the engine wiring. One is green fuel solenoid the other is black ignition kill wire, unplug the black wire and test for fire again.

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I’m actually thankful my mower acted up. Forced me to fix things along the way I didn’t know were wrong. I had a mouse nest on one coil .

I do think this surging may be the valve adjustment on the exhaust valve. I also think I have a timing issue. But, I did clean my crank case, replace coils, plugs, filters and carb so I should be running like new once the current issues are fixed

Jimmac said:

I’m actually thankful my mower acted up. Forced me to fix things along the way I didn’t know were wrong. I had a mouse nest on one coil .

I do think this surging may be the valve adjustment on the exhaust valve. I also think I have a timing issue. But, I did clean my crank case, replace coils, plugs, filters and carb so I should be running like new once the current issues are fixed

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Oh and I’ll add that the reason I’m not adjusting the valves myself is because the orientation of the engine in the mower severely restricts access so the motor needs to come out and I’m not set up for that.