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New guy issues. Scag 52 swz with Koehler 18

#1

Bluegrassfj40

Bluegrassfj40

Hey everyone. New here.
I have a couple dumb new guy questions.
- bought a used scag 52 swz with a kohler command pro 18.
- what powers the electric clutch? There is no battery on the mower. Is that normal?
- the clutch was not working when I got it. It failed the resistance check. I replaced it but the new part is also not engaging.
- checked voltage at the voltage regulator and it was 24v at full speed and 12v at low speed. So not working. Replaced that part but now it’s 12v at high speed and 3v at low speed and clutch still does not shift.

confused. Any help appreciated.


#2

B

bertsmobile1

We really need the full model number which should look like this SWZL52V-18????
That is a big unit to be pull start only
With electric clutched they burn out alternators , rectifiers & clutches at a rapid rate .
The Kohler manual can be found here K & T mower parts


#3

Bluegrassfj40

Bluegrassfj40

bertsmobile1 said:
We really need the full model number which should look like this SWZL52V-18????
That is a big unit to be pull start only
With electric clutched they burn out alternators , rectifiers & clutches at a rapid rate .
The Kohler manual can be found here K & T mower parts
Click to expand...
Swz52A-18KH is the model number.
Thx for the reply!


#4

Bluegrassfj40

Bluegrassfj40

Bluegrassfj40 said:
Swz52A-18KH is the model number.
Thx for the reply!
Click to expand...
There is a cover missing where the starter would go (can see the flywheel) and the top cover was loose. Who know what this thing went through my before I got it. Is it possible to tell from the model number if it originally had an electric starter?


#5

B

bertsmobile1

I can not but if you post the serial number from the mower some will
Sounds like the alternator went so they took the starter off then just used the emergency pull start from then on in
As previously mentioned running without a battery will kill the stator in a very short time
So the entire electrical system is suspect
The instructions for checking & testing is in the manual


#6

StarTech

StarTech

I seen setups where they use a battery-less charging system. Requires rectifier/regulator setup for this. This mower use such a system. Also it has a Kohler CV493T series engine but would need the serial as at two different specs were used. There are 27 different serial breaks on this unit.

And yes it is just a dummy cover where the starter would had been on the specs that used an electric starter.


#7

Bluegrassfj40

Bluegrassfj40

bertsmobile1 said:
I can not but if you post the serial number from the mower some will
Sounds like the alternator went so they took the starter off then just used the emergency pull start from then on in
As previously mentioned running without a battery will kill the stator in a very short time
So the entire electrical system is suspect
The instructions for checking & testing is in the manual
Click to expand...
Thx for the response.
Serial number is 9080045.
there is no battery on the mower and no place for a battery. I have tried to look up pictures of similar units to see if some of them don’t have batteries and it seems like some do not. I also seem to remember that there is a different stator and voltage rectifier/regulator depending on battery or not. Non batter is 15A and battery version is 3A. But I could be totally wrong with that.


#8

Bluegrassfj40

Bluegrassfj40

StarTech said:
I seen setups where they use a battery-less charging system. Requires rectifier/regulator setup for this. This mower use such a system. Also it has a Kohler CV493T series engine but would need the serial as at two different specs were used. There are 27 different serial breaks on this unit.

And yes it is just a dummy cover where the starter would had been on the specs that used an electric starter.
Click to expand...
Thx for the response. Helpful. I’ll look for the serial number on the motor. I believe the tag was damaged or missing but I’ll look again.


#9

StarTech

StarTech

Okay the engine is a Kohler CV493T-27526. Also the mower is a 2004 model.

Here is a link to the owners and parts manual.

Mower body
SWZ52A-18KH Owners and IPL Manual.

Engine
CV493-27526 online IPL

Note: The engine service manual don't cover this style of charging system.


#10

Bluegrassfj40

Bluegrassfj40

So I got another new voltage reg off of amazon. Doing the same thing as the previous new regulator. It’s putting out 14v at full throttle then drops out at half throttle to 3v. Other odd thing is the clutch won’t engage even when t he regulator is putting out 14v. I put the original regulator in it. Throttled it down to low speed. Putting out 12v and the clutch engages. Possibly not enough current out of the new regulator? Super weird. There has to be an answer out there somewhere:). Just have to find it.


#11

StarTech

StarTech

Have check the resistance of the electric clutch coil? If partially shorted they can still operate but draw excessive current which overload the charging system. I seen these clutches to pull nearly 20 amps and still operate. Normal minimum resistance is around 1.7 ohms any below that indicates a shorting winding. Also most electric clutches pulls under 7 amps with 3-5 amps being closer to normal draw.


#12

B

bertsmobile1

The body of the regulator is the ground connection
If it is mounted into the plastic blower housing , the mounting bolts need to have a ground strap to them
I make up 2 , one for each bolt .


#13

Bluegrassfj40

Bluegrassfj40

StarTech said:
Have check the resistance of the electric clutch coil? If partially shorted they can still operate but draw excessive current which overload the charging system. I seen these clutches to pull nearly 20 amps and still operate. Normal minimum resistance is around 1.7 ohms any below that indicates a shorting winding. Also most electric clutches pulls under 7 amps with 3-5 amps being closer to normal draw.
Click to expand...
Clutch is brand new oem part. It is right at 3ohms resistance which seems to be right in spec according to the mfg.


#14

Bluegrassfj40

Bluegrassfj40

bertsmobile1 said:
The body of the regulator is the ground connection
If it is mounted into the plastic blower housing , the mounting bolts need to have a ground strap to them
I make up 2 , one for each bolt .
Click to expand...
Good through. The housing is metal in this case. I don’t think I have a ground issue but could be wrong. I’ll check again.


#15

StarTech

StarTech

Bluegrassfj40 said:
Clutch is brand new oem part. It is right at 3ohms resistance which seems to be right in spec according to the mfg.
Click to expand...
Yes that would right. It was just a thought.

What is the AC input into the regulator? It needs to be at least 28 vac at 3600 rpm. If less than this then the stator is failing.


#16

L

lbrac

Bluegrassfj40 said:
Hey everyone. New here.
I have a couple dumb new guy questions.
- bought a used scag 52 swz with a kohler command pro 18.
- what powers the electric clutch? There is no battery on the mower. Is that normal?
- the clutch was not working when I got it. It failed the resistance check. I replaced it but the new part is also not engaging.
- checked voltage at the voltage regulator and it was 24v at full speed and 12v at low speed. So not working. Replaced that part but now it’s 12v at high speed and 3v at low speed and clutch still does not shift.

confused. Any help appreciated.
Click to expand...
Were the voltage readings that you took at the regulator taken w/ with the clutch engaged? How do the resistance readings of the disconnected (wiring) clutches compare? Have you checked the voltage at/near the clutch w/ and w/o it engaged? Could be a switch or wiring issue.


#17

Bluegrassfj40

Bluegrassfj40

StarTech said:
Yes that would right. It was just a thought.

What is the AC input into the regulator? It needs to be at least 28 vac at 3600 rpm. If less than this then the stator is failing.When I measured across both stators it was in the mid 40’s. I think when I checked each on it was around mid to high 20’s. I can check again tomorrow.
Click to expand...


#18

Bluegrassfj40

Bluegrassfj40

lbrac said:
Were the voltage readings that you took at the regulator taken w/ with the clutch engaged? How do the resistance readings of the disconnected (wiring) clutches compare? Have you checked the voltage at/near the clutch w/ and w/o it engaged? Could be a switch or wiring issue.
Click to expand...
Voltages at the regulator were not taken with the clutch engaged.


#19

I

ILENGINE

Has the replacement regulator been confirmed to be the 12 403 01-S or 12 755 111-S which is rope start only and not the 41 403 10-S or 25 403 37-S regulator which is for battery ignition.

Loose flywheel magnets can also give those types of voltage readings.


#20

Bluegrassfj40

Bluegrassfj40

Here is another piece of info that may help diagnose. The mower has an ignition key switch on the panel but it has been forced to on so it does not require a key. Curious if that may indicate that this mower was once an electric start model…. I’m just not sure if they all came with keys even if it was a pull start (assuming not). Curious if the guy I bought it from pulled the starter and battery off of it, put a cord pull start thing on the top and sold it to em. Just a hunch. Thoughts?


#21

I

ILENGINE

May not indicate electric start because it was common to have a two position key switch that were basically on or off, with no turn position for start.


#22

Bluegrassfj40

Bluegrassfj40

ILENGINE said:
May not indicate electric start because it was common to have a two position key switch that were basically on or off, with no turn position for start.confirmed that the wiring to the kit switch matches a manual start harness detailed in the owners manual.
Click to expand...
Good call. I confirmed that the wiring harness on the mower’s switch matched the harness associated with the manual start unit (as detailed in the manual)


#23

Bluegrassfj40

Bluegrassfj40

ILENGINE said:
Has the replacement regulator been confirmed to be the 12 403 01-S or 12 755 111-S which is rope start only and not the 41 403 10-S or 25 403 37-S regulator which is for battery ignition.

Loose flywheel magnets can also give those types of voltage readings.
Click to expand...
Well. I think you nailed it (I hope). The previous part I tried was the battery ignition on! I just ordered the pull start version. We will see!


#24

Bluegrassfj40

Bluegrassfj40

Well…. That wasn’t it. New Koehler voltage regulator for a pull start unit and it is still outputting 24v at full throttle. 48V ac across the two ac connectors. :/


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