diagnosing briggs ohv slow cranking

[Arkie]

Yes,
about a electrical arc burn frying my own skin and meat I will not forget and for few years bone type of pain in the finger in cold weather would re-surface.
I was really lucky that the burn was only through my pointing finger and not across my body.
I was working on an oscilloscope on the work bench that had a power supply issue and I cut loose a 2000 volt power supply tublar filter cap's solid wire and the cap was spring loaded and fully charged at about 1400 volts and the lead end of the caps wire all at once went from my knuckle on my pointing finger to the finger nail arcing and burning meat and skin. (all happened in like one second) I was really lucky that the end of my pointing finger that was holding the small wire cutter was the only thing grounded, no shock going through my body. Discharge and meat/skin burn was through the grounded finger only.
Finger not useable for awhile and took long time for new skin to grow. The smell of burning skin and meat is not a good thing when it''s your own.
Noticed later that no bleeder resistor was used on the HV power supply.

[KE4AVB]

Just doesn't sense that manufactures would avoid spending a few pennies in safety parts but I know they do it all the time. The power that got me had three 450 mfd 450 v caps in series. As I said it left the the three bleeders installed. Now of the linear came in only 500 watts PEP and left doing nearly 1500 PEP. A year later I was replacing my RF cables when I noticed they were blacken since they were only rated for 800 watts. Personally I had more contact using less than 1 watt then I did with 250 watts.

[38racing]

So I messaged him that I would pickup the mower. First off he said that it was currently ok. But I get there and he says battery is 12 something that I can only remember as being below my target of 12.4. So I bring it home and it cranks a bit and stops. Voltage is 12.07. I boost and it starts. Check voltage and 12.3 running. I'm wondering if voltage went from booster so I shut it off. Voltage is back to 12.07. Start and it's back to 12.30 and maybe 5 minutes to 12.4. I'm figuring that's no good for a mower with electric pto. This is a repower but the chassis connector is definitely a dual. My next test will be to check voltage at the connector right after the diode. Assuming it matches battery then needs stator? If much higher then it's wiring from connector to battery? He has a wire directly from b+ to a horn relay (for son). I can't see that being an issue but. I'll disconnect anyway.
Edit: appears from briggs info that proper test on diode output pin is an amperage test. I assume that I'll need to see a higher amperage here with pto off than being drawn from battery when pto on.
Also another question. Looking up briggs stuff i see the 5-9 alternator with 1 black lead to from stator to regulator and 1 red from regular to chassis. The regulator has hole in centre. ( mounting I assume). So then checking outside I find I have a Briggs on a jd from our scrap dumpster. Appears to have this 5-9 but there's a black wire on the centre mounting bolt that goes up under the flywheel with the other black wire. Don't see that yet in the briggs docs

[38racing]

I wonder if there is an internal difference between
790292 which gets inserted in dual harness and briggs claims increases current.
https://www.denparts.ca/12-volt-regulat ... _4EALw_wcB
and the regulator 794360 that's on my 5 amp dumpster engine
https://www.ebay.com/itm/Briggs-and-Str ... 3181685382

[SUKI]

First there is only one way to find out what's up with the engine on the JD but two black wire going under the flywheel is usually on a Briggs would normally be a 10A or larger stator but it sounds like altered wiring. Just too many wiring hackers to know otherwise.

Now as for the two regulators you listed they should be the same with just external differences in the way they are connected.

Anyway I would rather myself just change out the stator to higher amperage one and add the regulator that matches. The dual circuit with regulator is still going to be borderline amperage wise as you will be maxing out the stator even at full rpm and you will still have problems at lower rpms with it keeping up.

Don't take me wrong as the dual with regulator can work fine on some setups, it is just my preference to use a higher amperage system as to have some surplus available. From the electrical design I always like to have 50-100% in reserve. Otherwords when I build a power supply or other electronic circuit I build to handle more than the stated rated amount. But nowadays the manufactures are cutting it a lot closer to cut pennies from the costs.

[38racing]

First there is only one way to find out what's up with the engine on the JD but two black wire going under the flywheel is usually on a Briggs would normally be a 10A or larger stator but it sounds like altered wiring. Just too many wiring hackers to know otherwise.

Now as for the two regulators you listed they should be the same with just external differences in the way they are connected.

Anyway I would rather myself just change out the stator to higher amperage one and add the regulator that matches. The dual circuit with regulator is still going to be borderline amperage wise as you will be maxing out the stator even at full rpm and you will still have problems at lower rpms with it keeping up.

Don't take me wrong as the dual with regulator can work fine on some setups, it is just my preference to use a higher amperage system as to have some surplus available. From the electrical design I always like to have 50-100% in reserve. Otherwords when I build a power supply or other electronic circuit I build to handle more than the stated rated amount. But nowadays the manufactures are cutting it a lot closer to cut pennies from the costs.

I'm trying to decide on the stator switching or see if the engine on the JD is good. It would give him more HP. Back to original engine power. It's a 31 series so I'd do the head gasket just on principal. I'm also concerned that the current engine is consuming oil. I checked it before starting and it's at the add mark. Engine swap a bit more work too but possibly no flywheel popping. I hate doing the pto clutches. Concerned about getting the right torque.

[Arkie]

I did not read all of the previous posts but keep in mind that just changing stators to get more amps from some Briggs charging systems also requires compatible flywheel magnets. (larger magnets)

Those two regulators in your links appears to be the lower amperage half wave rectifiers.
The higher amp type of that configuration is a full wave type and will have two yellow wires for the AC and one red for the DC output.

Just couple thoughts about checking the charging system:
Have you tried testing the DC charging amps with a good know to be accurate DC Ammeter with the throttle at full open with the PTO OFF then with the electric clutch PTO ON?
With the electric PTO OFF the bat voltage should get close to 13v eventually. If it won't try charging the battery with a stand alone charger to see around 13v then see what the charge amps are with the engine charging system after the engine starts.
These tests are to see if the engine charger will charge the bat with the electric PTO off and then with the electric PTO on. I would also check the amps draw of the PTO clutch. If the clutch load amps in spec are more than the charge amps it's going to eventually drag down the bat volts. What does the amps gauge on the dash indicate for charge?

What is the average battery voltage when the engine is cranking?

[38racing]

Definitely a charging problem now lol. When trying to check voltage at the connector I managed to lift wire into contact with the flywheel. He confirmed that he's adding a lot of oil so I'm going to checkout the 31 series on the JD.

[Arkie]

I read on pg 1 that a new higher CCA bat was installed and still slow cranking
and on pg 2 it's a oil burner.


Appears it's time for the engine swap.

Before swapping the engines I would do a careful inspection of the crankshaft, PTO pulley and the other pulley so as to make sure they will swap for proper alignment of the belts.

[38racing]

I read on pg 1 that a new higher CCA bat was installed and still slow cranking
and on pg 2 it's a oil burner.


Appears it's time for the engine swap.

Before swapping the engines I would do a careful inspection of the crankshaft, PTO pulley and the other pulley so as to make sure they will swap for proper alignment of the belts.

current engine was a swap. The JD is actually closer to original, both 31 series. I had put a 28 series in it.