Riding mower wiring help needed

[Tynee]

Afternoon. I’m working on a Commercial grade Ransomes mower from the last century, I think. The second engine (I assume) poked a hole in the crank case, so my buddy bought himself a new B&S 21R807 to replace it. The wiring is not the same as the old engine.

I’ve attached the wiring diagram the way I’ve got the new one wired up currently. My issue is I can’t get the starter solenoid to fire consistently, and when the solenoid does fire, it doesn’t turn the starter. I’ve got 12.6 volts at the battery terminals, and when the key is off, I get 12.5 at the battery side of the solenoid, but as soon as I turn the key to run, I drop to about 7 volts at the battery side of the solenoid.

Anybody see anything I’ve got wrong? Any ideas why I’m losing voltage when I turn the key on?

 

[The Cobbler]

it looks like you have the battery & exciter ( what engages the solenoid from the key switch ) on the same terminals?

7v is low . maybe needs a battery too

take a pic of the solenoid

 

[Tynee]

No, exciter is the orange running to the spade terminal on the solenoid. The battery and the wire feeding power to the key switch are on the same terminal. The 3rd line is erased, though not very thoroughly.

 

[PCustoms]

What's the black going to the fuse, then switching to red?

Not sure if this is just "i ran out of wire" situation, or a wiring issue

Can you jump the solenoid to see if it's just a bad battery?

 

[The Cobbler]

these old eyes missed the orange exciter wire. sorry

 

[TobeyA]

1. Check all the connections, especially the primary ground. Poor connection= resistance= voltage drop.

2. Jump it from a car battery. If it works, it's probably the battery.

 

[Awag]

To me sounds like bad/dirty connection or bad battery. Leaning towards bad connection. You're loosing a tenth of a volt without a load. When you turn the key on you put a minimum amount of load on it and are dropping to 7 volts. I'm sure it drops even more when you try to start it. Check the voltage right at the battery if it drops to 7 volts with the key on you have a bad battery.

 

[Sumboodie]

That's a starter relay. A solenoid would be on the starter and push the bendix out and/or push the contact plates together.

Easy way to remember is solenoids do work, relays don't

 

[Tynee]

That's a starter relay. A solenoid would be on the starter and push the bendix out and/or push the contact plates together.

Easy way to remember is solenoids do work, relays don't

You’re right. Careless terminology by me.

 

[Tynee]

Ran out of tome on this last night. Left the battery charger on overnight, will try it again, double-check all my connections, then go with a new battery if I’m still having issues.

 

[Sumboodie]

You’re right. Careless terminology by me.

It's commonly misidentified... ID Ford starter relays that are on the fender of the older trucks. Lot of people call them the starter solenoid.

Just figured it might help you out in figuring out what's going on if you have to look at a OEM wiring schematic, as it should be labelled as a relay.

 

[Sumboodie]

Ran out of tome on this last night. Left the battery charger on overnight, will try it again, double-check all my connections, then go with a new battery if I’m still having issues.

I had a ~10 year old Diehard brand on my Craftsman tractor. Never had an issue with it. I fired it up a few weeks ago to wash it and put the tractor for sale and remarked that the battery was going strong even with it's age.

Buyer shows up, I go to fire it up and it's stone dead. Somehow the battery failed right there. I had to ask who did I piss off to get luck like that!
Ended up jump starting it and the buyer was happy with that. I offered to buy a new battery even, but he was excited to get the tractor I guess and was all set.

 

[KenC]

Normally the cause for such problems is a poor connection, particularly grounds. Don't forget the relay ground path. Try a jumper cable from the battery to starter relay bat terminal as an aid in isolating this. If the problem is in the supply path that will 'fix' it.

 

[rancherbill]

You've been fiddling around so I'd check ALL wires and grounds for damage and all connections for tightness and cleanliness.

Boost from a car to see if your battery is bad.

Go back to the original factory schematic there is a lot of stuff that's missing like safety interlocks and other stuff.

 

[rancherbill]

duplicate

 

[bwringer]

My WAG is ground; there's a lot of painted and bolted metal between the negative terminal of the battery and the starter housing, relay, etc. My trailer, for example, needed a ground wire between the tongue and the body because both parts were painted, and the bolted connection wasn't a consistent enough ground path.

Plain old bad battery is, of course, quite possible as well. I've seen more than a few motorcycle batteries show 12.5+ volts with no load, but that can't produce enough electrons to spin a starter.

 

[firebirdparts]

Probably just a dirty terminal. Location of the voltage drop to 7 volts has to be super obvious; find it. I have had quite a lot of trouble like this with my tractor at the battery itself.

 

[Tynee]

Thanks for all the input, gentlemen. Turns out it was a dead (practically new) battery. I believe it lost some battery acid during the process of the engine swap. When I jumped it from a car, the starter spun like a champ. Now I just need a new magneto armature due to some other foolish wiring, and it'll be good to mow with again. BTW, I know all the safety inlerlocks and stuff are gone. That was the hack-job of a prior owner. I've alerted my buddy (the current owner) to the dangers here, he seems comfortable with it.

 

[rancherbill]

Safety interlocks previously removed ........

I've alerted my buddy (the current owner) to the dangers here, he seems comfortable with it.

Your buddy is an idiot.

 

[ScottsGT]

Yea, at least the seat safety! I hated the back up safety on my old Cub Cadet. Turn key back one notch, press back up button to back up with blades engaged. It stayed on all the time. Funny how a ZTR doesn’t need this stuff.

 

[KenC]

Yea, at least the seat safety! I hated the back up safety on my old Cub Cadet. Turn key back one notch, press back up button to back up with blades engaged. It stayed on all the time. Funny how a ZTR doesn’t need this stuff.

That's 'cause nobody has won a huge personal injury suit against a ZTR maker,...yet. That was the genesis of backup safety switches.

 

[ScottsGT]

That's 'cause nobody has won a huge personal injury suit against a ZTR maker,...yet. That was the genesis of backup safety switches.

Very true. My old job was based in the sub level of a Law School. I use to go upstairs to the canteen all the time for lunch. On a cork board in the hallway was a poster that said:

You can thank a lawyer for….
Seat belts
padded dash boards
safety glass and tempered glass
collapsable steering columns
air bags in all cars now

And the list went on too. Each point had the law case listed if they wanted to look it up. But basically every safety feature in cars are because of lawsuits.

 

[Tynee]

Your buddy is an idiot.

Let’s go with “young and inexperienced.”

 

[Tynee]

Yea, at least the seat safety!

It’s not actually a rider, it’s a commercial grade walk-behind, and a very old one at that.

 

[ScottsGT]

It’s not actually a rider, it’s a commercial grade walk-behind, and a very old one at that.

Oh man, another forum I’m on there was a posting of a woman that was mowing on a hill and her husband had built a junkyard push mower with no safeties. Mower flipped and chased her down the hill taking chunks of flesh out of her **** and part of her foot if not all of it.

 

[Tynee]

I have warned him of the potential for a very similar scenario.