Lazer Z only starts with assist of battery charger

mowerman556

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Hello, looking for some assistance with a starting problem. My Exmark, model LZ28KC724 which I purchased in 2004 has developed its first problem. Two weeks ago when I went to start the mower, the indicator LED turned red as always, but the fuel pump did not kick on as usual. As a result, the mower would not start. After spending a good hour checking fuses and connections, on a whim, I connected my battery charger.

On the 10 amp charging setting, the same situation occurred. Keyswitch to on, red light, but no buzz indicating the fuel pump kicked on. Giving it one more shot, I changed the setting on the battery charger to the 55 amp "start" setting. Voila, the fuel pump buzzed, and the mower started. The mower continued to run until I finished and parked it back in the barn. On trying to restart it, the same thing occurred.

Based on the above, I installed a new battery. The old battery was 4 years old, so figured it didn't owe me anything. The battery shop tested the old battery, it had 215 CCA. The new battery was fully charged, and registered 320 CCA. Surprisingly, the new battery made no difference. I still have to connect the charger, on the 55 amp setting, in order to get the fuel pump to fire.

Anyone else run into this? I searched the forum before posting, but didn't find anything remotely related to this problem.

Thanks in advance, and happy Father's Day to all the dads out there!
 

Boobala

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A simple cleaning and tightening of your battery cables (BOTH ENDS especially the ground cable) along with being sure the start solenoid has a good ground and secure wires may be helpful.
 

bertsmobile1

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Run a heavy jumper from the - battery terminal to the engine ( drain plug is a good place or the lifting hook ).
Mower fires right up then you have a bad ground.
On most mowers the ground is made by the 1.5 turns of thread on the bolt that is threaded into the body.
The frame is fully painted then the engine is fitted and the engine ground is basically a couple of scratches.
On a few "problem" mowers I have run a ground strap directly to one of the engine mounting bolts secured with a 1/2 nut.
The whole lot then gets painted with liquid electrical tape, as does the main ground , after striping the paint under it & fitting a new zinc plated bolt.
Battery terminals get the same treatment.
I fit longer battery bolts, paint the entire terminal to prevent corrosion leaving 1/2" of unpainted bolt protruding to allow for measuring & jump starting.
 

mowerman556

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A simple cleaning and tightening of your battery cables (BOTH ENDS especially the ground cable) along with being sure the start solenoid has a good ground and secure wires may be helpful.

Thanks! I'll go through the wiring tomorrow morning. Too hot to do any outside work today, or even mow. Appreciate the response, and will let you know what if anything I find.
 

mowerman556

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Run a heavy jumper from the - battery terminal to the engine ( drain plug is a good place or the lifting hook ).
Mower fires right up then you have a bad ground.
On most mowers the ground is made by the 1.5 turns of thread on the bolt that is threaded into the body.
The frame is fully painted then the engine is fitted and the engine ground is basically a couple of scratches.
On a few "problem" mowers I have run a ground strap directly to one of the engine mounting bolts secured with a 1/2 nut.
The whole lot then gets painted with liquid electrical tape, as does the main ground , after striping the paint under it & fitting a new zinc plated bolt.
Battery terminals get the same treatment.
I fit longer battery bolts, paint the entire terminal to prevent corrosion leaving 1/2" of unpainted bolt protruding to allow for measuring & jump starting.

Thank you! That kind of situation might account for why I can get the mower to start when using the battery charger on the 55 amp setting, but not the 10 amp. The additional current might be the difference in getting a complete circuit. Strange that it would manifest after 14 years, and from one start to the next, but I have seen stranger things. Thanks for the reply. Greatly appreciated, and I'll provide feedback.
 

bertsmobile1

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Thank you! That kind of situation might account for why I can get the mower to start when using the battery charger on the 55 amp setting, but not the 10 amp. The additional current might be the difference in getting a complete circuit. Strange that it would manifest after 14 years, and from one start to the next, but I have seen stranger things. Thanks for the reply. Greatly appreciated, and I'll provide feedback.

Not strange at all.
Over time the original nice clean bolt rusts as dose the the body so the grounding slowly gets worse.
Because this happens slowly ove time you don't notice till one day it wont start at all.

FWIW it is always bet to jump to the + battery terminal and a good ground point on the motor.
I had a mower come in because the throttle wire was burning.
And sure enough smoke poured out of it when you started the mower and it was way too hot to touch, and yes the throttle wire was the only ground path to the engine.
 

mowerman556

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** Update to original post **

So, with input from Boobola and bertsmobile1 I cleaned the connections yesterday morning. I also made up a jumper wire with ring connectors on both ends. With one end connected to the battery negative post, I connected the other end of the jumper wirer to various points:

* The same lug on the engine as the wire from the battery
* The engine lifting hook
* Several areas of the frame
*The bolt that secures the muffler to the engine

Same condition each time, that is to say, no change. Each time I relocated the jumper wire I turned the key to the ON position but the fuel pump still did not cycle. I removed the jumper wire from the battery and set it aside. Connecting the battery charger, and being on the 55A "start" setting, the fuel pump cycled and the mower started. So, mowed that way yesterday, just cautious not to shut it off along the way. Soon as I parked it back in the barn and turned the key... nothing. Fuel pump doesn't cycle.

Oh, one more thing I did... unplugged the large plug on the left side, it's about a 50 pin or so connector. I assume this is where the ECU is located? I looked over the plug, it was clean, could not see any pushed pins, and it was still "slick" from dielectric grease, which I assume has been there since it was built. Reconnected it, and still no change.

Any other suggestions? Could the problem be a voltage regulator? Where is it located, and how do I test it?

thanks again,

mowerman556
 

mowerman556

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Replace the starter

Thanks, GrassBarber. Can you give me any more to go on? Is this something that's you've experienced? Is there a way to test the starter without replacing it first?

The reason that I ask is because the engine turns over and over with no problem with the key in the start position. It's just that it will only "fire" when the battery charger is hooked up, and only on the 55A setting. If I have it on the 10A setting for example, the mower cranks and cranks but still won't "fire". Here is what I've found in the Kohler Service manual which I found online:

When key switch is turned ON and all safety switch
requirements are met, ECU activates fuel pump module
for about six seconds, which pressurizes system for
start-up. If key switch is not promptly turned to start
position, engine fails to start, or engine is stopped with
key switch ON (as in case of an accident), ECU switches
off pump preventing continued delivery of fuel. In this
situation, MIL will go on, but it will go back off after 4
cranking revolutions if system function is OK. Once
engine is running, fuel pump remains on.

I'm not getting the six second buzz for the fuel pump module when I turn the key to the "on" position UNLESS the charger is connected, and on the 55A setting.

Thanks!
 

ILENGINE

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Sounds like a bad electrical connection with possible corrosion. Remove and clean all the grounds that you can find on the engine. Pay special attention to the ECU ground wires also.
 
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