2072 PTO Clutch Problem

[rcahoy]

Guys,
Does anyone know what voltage you should be getting down to the clutch on a Mag 20 on a 2072?

Engine not running I get 12.81
Engine running at full throttle it's 15.45!

What's causing it to spike so high? Will this burn out the clutch?

 

[sblunier]

Sounds like a "hot" voltage regulator. Wide open it should put out right at 14.5 volts.

With meter set to AC voltage, measure across outside 2 pins on the voltage regulator, you should read 29VAC.

If you are charging the battery at over 15 volts, that's too much.....

 

[sblunier]

Btw, check your meter, 12.85 is a little high for standard battery voltage....should be 12.5VDC...try a second meter, maybe yours reads high.....

 

[rcahoy]

Ok, checking the two outside terminals at idle it's about 15.6vac and at full throttle it spikes to about 40.0vac.

Is this a bad voltage regulator or could my wiring simply be routed wrong? This was a total restoration.

 

[sblunier]

Try a different meter before you do anything else. All of your readings seem high....

 

[sblunier]

Also, verify that the VR case has a good ground, then recheck voltages.

AC voltage should be roughly 2x DC charging voltage of 14.5vdc

 

[rcahoy]

I don't have another meter but I did check a different battery and it checked out at 12.5v so pretty sure the meter is alright.

I also ran another ground from the battery to the case of the tin on the engine to make sure it has a good ground so the VR should have a very good ground.

 

[sblunier]

Bad VR.....most likely.

 

[rcahoy]

Ok, I tried a different VR and it didn't make a lick of difference. Put the old one back on and it now is delivering a proper voltage of 14.4 at full throttle down to pto wire. So I think that is fixed?!?!? Not sure what might have changed, perhaps the VR wasn't properly seated or plugged in, but anyway it is doing what it's suppose to do.

Now when starting, sometimes it starts in an instant while other times it turns over very hard and slow. I don't understand how sometimes it starts great and other times it doesn't. WTH???

 

[nbextermueller]

the starters are notorious for wearing out. All of my Mag/KT motors have had worn starter issues. Once cleaned up and rebuilt, they spin like a top.

Its why a "how to" rebuild them is in the FAQ.

Getting those starters out without pulling the engine is the hard part!

 

[sblunier]

DB Electrical sells a good aftermarket starter...about $90 a copy last one I bought.

I have several "special" tools for those starters.....a stack of 1/4 drive extensions and a 7/16 gearwrench cut in half!

VR issue was likely the ground.

 

[nbextermueller]

Does the VR ground through the mounting screws or through on of the wires? My Mag20 in my 782 isn't charging enough under load. It shows a de-charge on the Amp meter when running both the headlights and PTO.

Think it might be the whole VR or just a grounding issue?

 

[sblunier]

Mounting screws, only 3 wires, 2 AC and 1 12vdc