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mouse
04-28-2008, 11:34 PM
Brand new mower (country clipper) has the Kohler 28hp efi motor 34 hrs. While mowing today the engine started to miss bad then nearly died, shut off engine thought it was low on fuel turned out it had plenty, tried to restart won't crank clicked like it had a low battery. I then jumped it and brought it home since the shop where I bought it was closed. I decided to check the battery it had 12.4 volts but still would not crank the engine without a jump checked voltage after the engine had started it was in the 13.6 range. Im having a little trouble guesing the cause. Keep in mind that it was running a little rough before I shut it off.

Thanks God bless

tacoma200
04-29-2008, 12:29 AM
You could do severe damage to some of the efi engines by jumping them. I'm not sure about the 28. Sounds like a bad battery except you said it started missing during use. 12.4 volts isn't good. Putting another battery on it for a while would rule that out.

Bill Kapaun
04-29-2008, 06:27 AM
A battery should be 12.6V.

mouse
04-29-2008, 11:19 PM
Turns out it was the voltage regulators ground to the engine cover was loose which ruined the regulator. Also the dealer jumped the battery when I brought it in. The battery was the first thing that they changed which wasn't the problem. Anyway thanks for the replies.
God bless

VegetiveSteam
04-30-2008, 01:26 AM
WOW...The dealer should know better than to jump start an EFI engine. That is something you never ever want to do. At least on a Kohler. You may get lucky a few times but one of these times you are going to blow the ECU and there's 300 bucks not covered under warranty. ECU's don't like voltage spikes. Glad it's working correctly now. A loose ground would for sure keep it from charging properly but can't say I've ever seen that damage a regulator. But like I said. Glad it's working now.

TOOMUCHWALKING
04-30-2008, 10:01 AM
I keep reading not to jump the Kohler EFI, but I've done that dozens of times and it's fine. I do, however, let the booster pack recharge on the mower for a while

tacoma200
04-30-2008, 02:09 PM
Glad it was an easy fix.

mouse
05-03-2008, 10:54 PM
These engines have a bosch fuel injection a lot like your cars or trucks you can jump them without harm. If you use a 12v battery and don't start the one you are using to jump with where would a voltage spike come from? 12v mower 12v truck.

TOOMUCHWALKING
05-03-2008, 11:16 PM
Some Harleys have fuel injection-I wonder if this is the same layout ? Makes me wondert if a Harley engine would fit the Lazer Z ?:weightlifter:

tacoma200
05-04-2008, 12:40 AM
These engines have a bosch fuel injection a lot like your cars or trucks you can jump them without harm. If you use a 12v battery and don't start the one you are using to jump with where would a voltage spike come from? 12v mower 12v truck.

Kohler advised against it is all I can tell you. There used to be lot's of reports of problems when the 28 first came out after jumping them. I don't have an explanation, just reporting what used to be considered common knowledge. I have no idea if it was true.

S DIAMOND
05-04-2008, 12:34 PM
If you use a 12v battery and don't start the one you are using to jump with where would a voltage spike come from? 12v mower 12v truck.
The very act of removing the battery cable from one of the terminals incorrectly, (whether charging or jumping) increases the chance of arching ( which we all have seen ). This arching ( the desire for the connection to stay together) causes a substantial VOLTAGE SPIKE in the system, similar to what your spark plug does when its jumping the air gap. The voltage spike is shot through the electrical system, in which case the ECU is not designed to absorb. This is the concept behind Points and condensers in older ignition systems. The condensers (aka capacitor) absorbed the spike across the points when the contacts opened, thus cutting down on damage. Just because the "systems" are similar does not mean they are the same. Your vehicle has some contingency built in to absorb stupid mistakes, not always true with small engines.

I keep reading not to jump the Kohler EFI, but I've done that dozens of times and it's fine. I do, however, let the booster pack recharge on the mower for a while

Depending on the weapon of choice, in Russian Roulette, you have one in six chances of winning each time you pull the trigger and spin the barrel. Keep trying you may succeed.:)

Important Service Notes!
• Cleanliness is essential and must be maintained
at all times when servicing or working on the EFI
system. Dirt, even in small quantities, can cause
significant problems.
• Clean any joint or fitting with parts cleaning
solvent before opening to prevent dirt from
entering the system.
• Always depressurize the fuel system through the
test valve in fuel rail before disconnecting or
servicing any fuel system components. See fuel
warning on page 5B.2.
• Never attempt to service any fuel system
component while engine is running or ignition
switch is "on."
• Do not use compressed air if the system is open.
Cover any parts removed and wrap any open
joints with plastic if they will remain open for
any length of time. New parts should be removed
from their protective packaging just prior to
installation.
• Avoid direct water or spray contact with system
components.
• Do not disconnect or reconnect the wiring
harness connector to the control unit or any
individual components with the ignition "on."
This can send a damaging voltage spike through
the ECU.
• Do not allow the battery cables to touch opposing
terminals. When connecting battery cables attach
the positive (+) cable to positive (+) battery
terminal first, followed by negative (-) cable to
negative (-) battery terminal.
• Never start the engine when the cables are loose
or poorly connected to the battery terminals.
• Never disconnect battery while engine is running.
• Never use a quick battery charger to start the
engine.
• Do not charge battery with key switch "on."
• Always disconnect negative (-) battery cable lead
before charging battery, and also unplug harness
from ECU before performing any welding on
equipment.

VegetiveSteam
05-05-2008, 02:29 PM
These engines have a bosch fuel injection a lot like your cars or trucks you can jump them without harm. If you use a 12v battery and don't start the one you are using to jump with where would a voltage spike come from? 12v mower 12v truck.

Again...NEVER jump start a Kohler EFI engine. The voltage spike comes from removing the jump source from the dead battery. When you remove the jump source the charging system of the now running engine spikes to full charge. While you have the jump source attached to the dead battery the charging system may be putting out little or no charge depending on the voltage of the jump source. When you remove that source the charging system now goes to full charge causing a voltage spike in the system and that can and WILL eventually damage your ecu. Of course you are more than welcome to do whatever you like and I like nothing more than to sell ecu units or any parts for that matter. For about the last year or so Kohler has been using a voltage regulator with spike protection built in but even Kohler will tell you that while that does reduce the chances of damaging the ecu it is not a gaurentee. You should also never jump start a Kohler engine with Smart Spark ignition for the same reason.