Agco 918H w/Command engine

[Tarheel]

  I got my 918 started and pulled into the shop a few nights ago but had picked up some kind of bug (Flu ?) that pretty much put a stop to doing anything more. The bug is almost gone but still weak. Anyway, I noticed again something I had asked about here before but have forgotten the answer to. When I turn off the switch, the engine keeps running on one cylinder for a bit before it dies. Any ideas as to what could/would cause this and how to repair ?

  Sorry, I have no knowledge of these engines. They came along after I was out of that line of work.

 This is the last year of the BGB tractors I believe. Bought new in 2002 or 3 I think it was, from a dealer with a warehouse full. When they stopped production he purchased all he could get. Though I was the one to pick up the machine for the family, I was in no shape to use it at the time. My youngest brother did the mowing for my grandmother and mom. He ran the engine low on oil and threw a rod then had the engine short blocked at a dealer who didn't get something right and from that point on the thing has had this ignition problem. Shortly after this mom asked that I take over the mowing again.

 This is when I learned that the thing didn't want to pull a hill and ran away downhill. I was afraid there was a problem with the hydro but turned out it was wear in the shifter and lever. You could move the lever full forward and the cam for the Sunstrand hardly moved. One of our members fixed me up with all the parts I needed (At a good price IMO. Thanks again) for those repairs and as soon as I'm able, I plan to make it happen. There are a number of other small problems like cracks in the seat pan etc and maaybe I can take care of that as well. It was parked for a good while. Thinking 5 years but likely more. When I pulled it into the shop I checked the air flow across the heads and didn't feel any so looks like the engine comes out to check for mouse nests.

 The finish on this tractor is very likely beyond repair. Sun faded and rough. Am I correct in thinking this was powder coated ? I seem to recall trying to buff  it at some point  and it didn't make a mark. If anyone has ideas about saving the finish please share. Thanks.

[Ronald Hribar]

The motor will shut off in two ways

normally it does both at once

first way is that it shorts the coils out

usaually when that does not work

the gas shutoff solenoid on the carburetor shuts off the gas to carb

and the motor stops

the coil shortening system uses a diode on it

it is also possible that one of the coils does not have the shut off wire connected

[SmilinSam]

When you turn the key off it does 2 things . It shuts the fuel off to the carb and also grounds out the cylinders.

There is  supposed to be a fuel shut off solenoid on them that shuts the fuel off when the key is turned off. Normally when these go bad the solenoid will not open and you wont get fuel to the carb.. I suppose it could not be closing for some reason when the key is off.

 I would also have to wonder if the one cylinder isnt being grounded out when the key is turned off for some reason.. 

[PhanDad]

As @SmilinSam said, when the key is turned to off, both cylinder magnetos are grounded.  The ground (white) runs across the top of the flywheel and under the intake manifold as shown in this pic.  

I'm betting it's the left side (as sitting on the tractor seat that's not shutting down.  Either the magneto kill wire wasn't reconnected or the wire running to it is open (no continuity).  

I also think the fuel shutoff solenoid is working.  Lack of fuel shuts down the "unkilled" cylinder.  

 

[Tarheel]

 My thanks to all of you for the replies. This should get me on the correct path.

[PhanDad]

16 hours ago, Tarheel said:

Am I correct in thinking this was powder coated ?

The frames of the late Sovereigns were powder coated and were susceptible to what I call sheet peeling. I think moisture gets under the coating ( or through it), rusts some and the paint peels off. 

I haven’t seen that happen with the hood or seat pan. I don’t know if they were powder coat. 
 

[SmilinSam]

1 hour ago, PhanDad said:

The frames of the late Sovereigns were powder coated and were susceptible to what I call sheet peeling. I think moisture gets under the coating ( or through it), rusts some and the paint peels off. 

I haven’t seen that happen with the hood or seat pan. I don’t know if they were powder coat. 
 

Mid 80's and up to the end in the late 90's  Wheel Horses were terrible for this("sheet peel") as well. With those it was belt covers, decks, and all the steel painted parts bolted to the iron tractor frames.

[PhanDad]

On 2/5/2024 at 7:04 AM, Ronald Hribar said:

the coil shortening system uses a diode on it

No, only the fuel shut-off solenoid has diodes in each power source:

1) Ignition switch "start" position to provide voltage to open the fuel shutoff solenoid to start the engine.
2) Then power from running engine rectifier or battery via ignition switch to keep the engine running.

For wiring novices, the diodes prevent current back flow - especially important in this case to prevent the starter from being constantly energized even after the tractor starts and the ignition switch is moved to the “run” position.  

 The diodes are shown in this Kohler Command "internal" wiring diagram:

 

[Ronald Hribar]

My mistake Briggs uses the diode

Kohler does not

[ShaunE]

On 2/5/2024 at 12:30 AM, Tarheel said:

He ran the engine low on oil and threw a rod then had the engine short blocked at a dealer who didn't get something right and from that point on the thing has had this ignition problem.

So this kind of tells me it wasn’t short-blocked but re-powered with a Command. The original of that time period should have been a Triad. Not sure what wiring changes need to be done for this but the Command has the solenoid on the starter & the Triad has it under the dash. I do know the wiring harnesses are different but I don’t know what those differences are. This is where @PhanDad needs to shed some more light on my electrical knowledge darkness.

[PhanDad]

23 minutes ago, ShaunE said:

So this kind of tells me it wasn’t short-blocked but re-powered with a Command.

Good thought - I didn't consider that the tractor was purchased new in 2002 or 03.  Very, very unlikely it was a new Command powered Sovereign.

@Tarheel, what's the MFG# of your 918H?  That will confirm Shaun's thought.  

With that in mind, I wouldn't think the "internal wiring" of the new engine was messed with on the Command install done at a Dealer's.  Maybe the ignition module(s) went bad (a somewhat common problem) and the "kill" wiring was messed up at that time?  

34 minutes ago, ShaunE said:

I do know the wiring harnesses are different but I don’t know what those differences are. This is where @PhanDad needs to shed some more light on my electrical knowledge darkness.

I believe wiring changes for most Command installs into previously installed Triads was to:

1) Move the heavy gauge "start" wire from the "output" side of the dash mounted solenoid to the "input" side - this in effect extends the heavy gauge wire from the positive post of the battery.

2) Connect the other end of the above wire to the "input side" of the built in solenoid (output/power side) on the Command engine starter.  

3) Run a new wire from the "output" side of the dash mounted solenoid to Command starter solenoid "control input".  (This is the orange wire Al Eden's Command Install Instructions) This wire could be ran directly or "go through" the tractor wiring harness/engine wiring harness plugs.  ( See next step)

4) The existing white kill wire and red/blue trace "battery" charging wire in the tractor wiring harness engine connector are connected to the Command engine.   Unfortunately the Triad powered Sovereign engine harness connector and the Command harness have the same gender connectors.  So either the harness connectors are abandoned and the wires are wired individually (hopefully with disconnects) or the gender of the tractor engine wiring harness is changed as described in detail in my " Triad Replacement - Command" post.  The offending connector:

 

Al's Wiring Page:

[Tarheel]

4 hours ago, ShaunE said:

So this kind of tells me it wasn’t short-blocked but re-powered with a Command. The original of that time period should have been a Triad. Not sure what wiring changes need to be done for this but the Command has the solenoid on the starter & the Triad has it under the dash. I do know the wiring harnesses are different but I don’t know what those differences are. This is where @PhanDad needs to shed some more light on my electrical knowledge darkness.

 I wasn't there when the engine work was done so I really can't say.  But something I do not understand is this. The engine has a small sticker just under the factory engine label. It reads as follows- engine serial no. 4021003411   .  I would have thought that a new engine would have the original label but maybe I'm mistaken. It is in fact a command CH18 now anyway.

 Not that I question what any of you say. Believe me, I am very grateful to all  of you that try to help. Without that help I don't know how I'd ever get things done on this newer (to me) equipment.  I do not remember what engine was in this tractor when I bought it. And I wouldn't know a Triad if it bit me. Don't know that I've ever seen one.

 I don't have anything to report as for progress. I felt much better yesterday morning but seem to have gotten over it. I have spent most of the last 24 hours sleeping trying to recoup. But boredom is pushing me and I may get in a few hours tonight if able.

 As always, Thanks

[Tarheel]

I'll see if I can get out there with my phone and check the mfg number. Okay, 1692452.

[PhanDad]

@Tarheel

MFG# 1692452 OEM engine was a Kohler Command Model CH18S, Type PS62513 per the 2005 Simplicity Engine Manual. 

Also, I have seen number stickers that come with short blocks with the instructions to apply them under the original engine stickers. 
 

[Tarheel]

3 hours ago, PhanDad said:

@Tarheel

MFG# 1692452 OEM engine was a Kohler Command Model CH18S, Type PS62513 per the 2005 Simplicity Engine Manual. 

Also, I have seen number stickers that come with short blocks with the instructions to apply them under the original engine stickers. 
 

 Thanks.

[Tarheel]

Other than going out yesterday to get the mfg number for the Agco, today was my first forage outside in a while. I have a lingering cough but otherwise feel I have shaken the flu or whatever I'd had.

 But, I seem to have lost the drive I'd had for getting the Agco set to rights. This isn't my norm and I imagine I'll get back to it soon.

To pass the time I have been getting garden seed ordered. Cantaloupes will take the place of most of the sweet corn I grow most years. They are calling for rain this weekend and I'd like to till the garden before it hits. I also wanted to move the tiller from the 7117 to the six speed.

 I stopped there and went out to the shop. I pulled the Agco out and the OP B&S 7119 in to remove the rear lift from it. got that done and will try and get the 7010 in tomorrow and switch all lift parts to it. Lastly, the 7117 tiller tractor will come in and have the tiller removed and a deck put under it. Out it goes and the 7010 comes in to get the tiller. Then I can get back to the Agco. Maybe LOL.

[Tarheel]

 I got the lift lift installed on the 7010 but haven't yet moved the tiller to it. I had planned to do so but the battery had laid down on the tiller tractor and then it started raining. Been sick long enough and didn't care to push my luck. Heavy rain/storms called for over the next couple of days so may be mid week before I get back to the Agco.

[Tarheel]

Got the tiller tractor pulled around and started to move the 7010 out of the shop. Started then died. Checked and found weak spark issue. Cleaned up the points and replaced the spark plug. Now I have good spark and no start (This old Briggs was changed to battery ignition at some point)

 Started looking at the fuel and found it wasn't getting any. Started to replace the fuel lines when it broke off in my hands back near the tank.  Lost about a pint of fuel on the floor and gave it a few hours for the fumes to clear and heading back out now to replace the line from the tank out.

 The 7010 is now done. The tiller tractor is in the shop ready to have the tiller removed. I guess the tiller tractor will become the 7118 and the 7010 will become the tiller machine.

 

[Tarheel]

 Got the tiller on the 7010 just now. Everything seems to work as it should but won't be sure about the cone clutch until the ground dries and I can work it a bit.

Now it's time to get back to the Agco. I would have started  on it tonight but the muffler is bad and even at idle, it isn't something I wish to subject those living near me to at 1 AM.

 I looked the muffler up. It is still offered, if you care to call it that at $600+ Guess I'll be putting the welder to work soon.

 

 I still need to get a deck under the 7118. And that tractor needs to be serviced as well. It hasn't seen many hours since being put on tiller duty. 5 to 10 hours a year would be a good guess. Though because of the added weight of the tiller, it has been my go to pulling tractor. I made a bar to mount on front that holds a 17/8 hitch ball to move the boats or small trailer. It is also the go to machine when a tractor needs a jump start and I can't reach it with the charger.

[Tarheel]

 Though the ground is really wet, I couldn't stand it and ran a pass and back with the 6 speed and tiller. It (the ground) will be fine if it doesn't dry to fast.

The tiller works just as it should as far as I can tell with wet ground.  The manual lift is the reverse of what my old B10 was. Meaning I have to pull to lift with this one. Not a problem except I have to pull it back till it is hard to hold the thumb latch and I'm pushing down as much as pulling. It also pins my leg at that point. I'll play with the adjustment on the cable later on and if that don't suit me I'll try and figure a way to reverse it.

 The Agco is in the shop ready for me to start on it. I guess I'll pull the engine first thing and pull the blower housing to check the wiring and for mouse nests. With the engine and battery out I can stand it up and get the shifter parts changed out. I hope anyway.

[Tarheel]

 Got word today that the frame for my uncle's 62 Ford is ready to go now. The plan is to roll/back the frame into the shop and set the body on it. Once it is gone ( over the weekend we hope but by next Wednesday for sure)  I'll set about working to set up tool locations. So it may be a while before I get the work done on the Agco.

 But then again, It is 52.5 degrees and I have all night..LOL

[Tarheel]

 The Ford is gone Now the real work starts.

[Tarheel]

 I knew getting the body out would open up more room, but had no idea just how much. To give an idea, welders, parts and tools/boxes are stacked to the rafters over much of the 3 walls.

But there is a JD 318 with a 4x6 trailer behind it parked in the shop now. And room for 2 more of the same. Room enough that I could get the Agco inside and still work on the rest but I won't for a bit. There is a good deal of items that need to be removed to the scrap yard or dump. Old grills that have rusted while sitting and so on. Parts that I can't see ever needing. (IE old starters and starter generators for vertical engines that I no longer mess with) All the foot dragger parts will go to my cousin and there are quite a few. Mower decks and other parts.

 2 of my 17 welders (counting a plasma cutter) will go to scrap and 2 I will find someone who needs them and give away. (If you live within driving distance of western NC and want or need a small welder, send me a PM) One is a MIG and the other a stick. Both 110v.

 Some of those left will be put up for sale.

 Once the scrap and trash have been removed I can start setting things up and getting all my tool boxes in one place, all my welders in one place and all my knife making tools in one place. The tools and tool boxes will take up the most space but will  need the least moving. But I have a newer large top and bottom box that is still mostly empty. I hope to relocate tools from some of the older smaller boxes to that and use the old ones for small knife making tools like clamps and jigs etc.

 This evening after sweeping, I pulled the tiller tractor back in the shop. I worked on getting the headlights working and adjusting the lift cable. The lights were a bit of a pain. No switch, no power and no ground. By the time the lights would work and the adjuster was loose on the lift cable, my hands were cold so I came inside. I hope to finish that tractor tomorrow. I need to remove the instrument panel and install a toggle for the lights and get it wired. I also have an ignition module to try on it but it runs as is so that may have to wait.

 

[Tarheel]

 Got the lift adjustment finished for now. Still not liking the pull to lift for some reason. But I'll get over it. Will likely have to go back and back that adjustment off as I don't think the tiller is going deep enough.

 The headlight switch is wired but there is still a problem with a weak ground. Not yet sure how I will try to manage that. Likely run a ground strap from the engine block or frame to the hood.

 After a good look sat the wiring, I think I will hold off on the ignition module for now. (Until the tiller isn't needed)

[Tarheel]

 I pulled the OP Briggs 7119 back into the shop. I had ordered a sealed beam headlight for it and installed the light and a switch as well. These lights seem better than those 1196 bulbs on the 7010 but can't be sure till the ground issue is taken care of. Before doing much more I'll put a set of off road LEDs on it.

  Still holding off on the Agco. Don't want to pull it down and have to wait on parts. Most of what I have left is much the same. My 318 needs the carb built and paint. Those Onan carbs can be a bear to remove but I think I have cleaned them while still sitting on the intake.