Ingersol 446 Vanguard re-powering wiring

As I understand it, Vanguards have their own ignition coils that use magnets on the flywheel to create the spark. In other words, if you spin the engine over, it will start even though you are not applying 12 volts to anything other than the starter motor. However, if you want to shut the engine off, then there is supposed to be a wire that goes to a NEW ignition switch that grounds out those coils to stop the electricity from going to the spark plugs.

I also understand that they have a separate alternator coil that puts AC voltage into a built in voltage regulator/rectifier that converts the AC voltage to DC. It sounds like the purple wire should be connected to the ammeter. Logic would dictate that the red lead is the one that gets grounded but that won't happen if it is connected to the former wire that supplied 12 volts to the Onan coil. Do their instructions not say anything about installing a new ignition switch? Those switches are available from Brian as they were used on all the Vanguard powered 4 digit tractors but you must add a ground wire to those switches to make them work, I believe.

I'm sure that one of the guys who are more familiar with this conversion will be along later today so just hang in there.

Chiming in on Vanguard repower,
The kit that I bought has a relay that handles the differences in the ignition systems.
First off the Onan needed +12VDC from the key switch for ignition. The Vanguard ignition system needs to be grounded to shut off the engine. The relay performs this function so you don't have to replace the ignition switch and rewire the tractor. The former Onan ignition wire now goes to the relay operation circuit. Secondly the Vanguard still needs + 12VDC to the fuel shutoff solenoid that is located in the carb. So the keyswitch + 12VDC is still needed for both of these functions.
The Vanguard has it's own regulator/rectifier so the stock Case regulator/rectifier can be removed from the tractor. The single wire from the Vanguard regulator/rectifier can be connected into the electrical system in the same place where the stock regulator/rectifier was connected. I don't recall the wire colors and my Ingersoll tractor isn't here at the moment to look at.
I hope that this info will help you.
Bob MacGregor in CT :thumbup:

According to Briggs and Stratton's website, model 350000 does not exist. There should be a tag on the engine itself that shows the Model number, the Specification number and the Serial number.

For sure, the Model number is needed.


The Spec number indicates all of the minor changes that the basic engine was ordered with.

Sometimes, only a 3 amp alternator is needed but 15, 20, 25 and 30 amp alternators are available.

Sometimes a pull starter is needed as well as electric start.

Sometimes a gas tank is need and sometimes not.

That's what the Spec number tells us along with details about the crank output shaft and whether a gear reduction has been added.

According to Briggs, the tag should be on a valve cover.

If we have those numbers, we may be able to locate the Service Manual for your engine and determine by way of the wiring diagram, what wire goes where.

After spending the last half hour trying to locate a SERVICE MANUAL for your engine on-line, I have concluded the Briggs guards these like Fort Knox guards gold. STUPID< STUPID< STUPID.

As I said in my initial post, the Onan uses conventional coil ignition. The coil is nothing more than a transformer that converts 12 volts DC to about 15,000 volts that is used to create a spark inside the combustion chamber. If you turn off the 12 volts to the coil, there is no spark and no combustion of raw fuel. Therefore, the engine stops running.

The Vanguard does not use a conventional coil ignition. Instead it uses what is called a magneto ignition that uses magnets on the flywheel to induce voltage into coils of wire a few thousands of an inch below the spinning magnets. There is no need to supply 12 volts to those coils but you must short those coils to ground to take away the spark and make the engine stop.

So how do we do that?

On the 3000 and 4000 series tractors, Ingersoll uses an ignition switch that does ground out these magneto coils when the key is rotated to the off position. Mackie as pointed out that SEW used to provide a relay with their re-power KITS as a solution to this problem found on tractors that used coil ignition. Apparently, you did not buy a KIT....just an engine that is suitable for re-powering a Case tractor. If I am correct, then that is what you need to overcome.

Mackie also mentioned that Vanguards normally have a fuel shut-off solenoid in the carb and therefore, there should be a wire coming from the carb that is going to need 12 vdc applied to it by the ignition key every time you want to start the engine or no fuel will get through.

I will call SEW tomorrow morning and ask their Tech people about these issues. If you have an invoice number for your purchase and the date, please PM it to me so that I have accurate info to go on. For today....you are screwed but we will get this sorted out tomorrow.

Hi Troops,
From looking at the pics he did purchase what SEW calls 356447-1-Case446 kit. I can see in the pics that there is the relay and it is wired to be connected into an Onan powered Case. What I also did see was a non Case/Ingersoll keyswitch unless the lights on this tractor are operated by a separate switch from the keyswitch. The regulator/rectifier output is a red wire and the fuel shutoff solenoid is a red wire and are wired to the relay and all comes down to two wires. One goes to the ignition terminal of the keyswitch and the other which is from the charging system goes to an accessory terminal on the keyswitch. But I think that there is a non standard keyswitch installed in this tractor, but I could be wrong. A side mount muffler and crossover pipes should have been supplied with this kit from SEW. I see the front PTO mounted and the hydraulic pump mounting bracket and half of a LoveJoy coupler.
Mad Mackie in CT :crazy: :lolno: :lol:
Tom, B&S service manuals must be bought, B&S part # 272144, but parts manuals can be downloaded from the B&S site.
I just went back to the pics and I did see the exhaust pipe in front of the dipstick tube.

Further inspection of the keyswitch in the pic indicate that it is a stock Ingersoll keyswitch. The terminal at the 6 o'clock position (red wire) is the ignition terminal. In the SEW harness there is a lavander colored wire and this is the charging system output. The other wire is red and this is the power to the relay. Ultimately both of these wires are connected together at the ignition terminal.
When connected, key off, the relay fails into a position that grounds the Vanguard ignition system, also the fuel solenoid in the carb is shut off. The charging system output circuit is open as leaving it connected to the battery, it will discharge the battery fairly quickly.
When the key is in the on position, the relay is energized, opening the ignition ground and opening the fuel solenoid in the carb. The charging system output is connected to the battery and will charge the battery with the engine running and the charging system putting out more that the tractor electrical system is using. This will indicate on the ammeter.
Bob MacGregor in CT :wave: :shock:

I ADDED CAP NOTES TO MAC'S LAST POST... PLEASE COMMENT AFTER LOOKING AT THE PICTURE OF THE DASH SWITCH WIRING AGAIN IN MY ALBUM --- Further inspection of the key switch in the pic indicates that it is a stock Ingersoll key switch. YES IT IS STOCK. The KEY SWITCH terminal at the 6 o'clock position (red OR blk/wht wires in the picture) ATTACH TO the ignition terminal. In the SEW harness there is a lavender colored wire and this is the charging system output. The other wire is red and this is the power to the relay. CORRECT. Ultimately both of these wires SHOULD NOT BE connected together at the ignition terminal. OTHERWISE I BELEIVE THE ENGINE CANNOT BE TURNED OFF AT THE SWITCH WHEN STARTED!!!! WHEN THE LAVENDER HARNESS WIRE IS CONNECTED TO THE AMMETER POST (SAME TERMINAL AS THE FUSE CONNECTION) AND THE RED HARNESS WIRE TO THE IGNITION SWITCH TERMINAL. Key off, the relay fails into a position that grounds the Vanguard ignition system, also the fuel solenoid in the carb is shut off.

THE POTIENTIAL PROBLEM IS THIS >>>>The charging system output circuit is open SINCE THE BLUE WIRE COME FROM THE ++ BATERY TERMINAL TO THE SOLENOID THEN TO THE AMMETER (RIGHT SIDE TERMINAL, SO leaving it connected to the battery, it will discharge the battery fairly quickly. HOW?? CURRENT GOING BACK TO THE RECITIFIER? MAYBE A SOLUTION WOULD BE TO ADD A SEPARATE KILL SWITCH TO CUT CURRENT FROM THE BATTERY GOING BACK TO THE ENGINE LAVEDAR WIRE WHEN THE ENIGINE IS OFF??

When the key is in the on position, the relay is energized, opening the ignition ground and opening the fuel solenoid in the carb. The charging system output is connected to the battery and will charge the battery with the engine running and the charging system putting out more that the tractor electrical system is using. This will indicate on the ammeter.

Hi jski,
Look at the wiring diagram that you posted in the gallery and you will see that the ignition wire and the charging system output wire are connected to the same terminal on the key switch in the Onan configuration.
If the charging system output would keep the engine running as you suspect, then this would be happening to every Onan powered Case/Ingersoll tractor made.
The reason for opening the charging system output when the engine is shut off is to prevent discharging the battery back thru the circuit. Because of the design of a basic half wave charging system which is what these systems are, if battery power is still connected the stator wants to turn the flywheel and motorize the charging system.
I still don't have my Ingersoll 4018 that I repowered with a Vanguard kit here to look at at the moment but I will be picking it up soon. But my the Onan in my 4018 had the engine mounted regulator/rectifier but no ammeter and it was a quick and easy setup electrically. Were I to repower a Case/Ingersoll with an ammeter I would remove the ammeter and install a voltmeter.
Bob MacGregor in CT :mowlawn:

The wiring kit instructions from SEW is dated 2009. It is copy protected so I will not post a picture of it. However on page 7 it shows the wiring harness only numbered at each lead. (same wire colors shown in my pictiures conned to the relay) On page 8 a picture of the engine mounted on the tractor with the harness wires attached to the engine. (same as my picture in the post). So the instruction they give are as follow:

Free wires to connect to tractor
1) lavendar lead >>> POWER TO AMP GUAGE.
2) red lead >>> CONNECTS TO THE COIL

Wires connected to relay and engine wires
3) gray >>> connect to the fuel solenoid
4) white >>> connnects to coil kill relay
5) red >>> power to engine from coil
6) lavendar >>> power from engine
7) gray >>> connects to fuel solenoid
8) white >>> Connect to engine coil stud

Last the kit has a stamped steel mount plate that elevates the new engine to OEM hight specifications.

Re: Ingersol 446 Vanguard B&S re-powering summary

It has been a while but I have the Small Engine Warehouse (SEW) re-powered B&S 18hp engine in the 1986 446 and have mowed ten times now. After I got the engine wired properly using a SPDT relay off of the OE switch everything went well. Thanks Mac!! (See my album for pics of the results). The mower deck is also rebuilt to new condition.

Food for thought for the next guy&#8230;. To get the SEW B&S conversion in the tractor and set-up right I had to modify several things:
1) The pump bracket hardware (diameter was .005" undersized)
2) Front end engine hub undersized .004" preventing easy clutch assemble.
3) I also notched out the engine mount plate to allow for clearance of the push rod that engages the mower clutch. SEW must have missed this aspect or they designed it for the newer electro-mechanical clutch.
4) I fabricated a manifold heat shield to prevent heating up the battery and hydraulic reservoir excessively. The air flow and lack of heat shields is a negative to the conversion kit. Yet even with my adaptations the engine compartment still gets pretty hot regardless. I made and mounted an air deflector on the muffler side so the heat coming out of the engine compartment and exhaust doesn't burn the operator leg. (See pic) Caution -- the operator should not wear short pants if the air deflector is not added. However in winter operation you can wear shorts.
5) The styling angle or position of the hood is acceptable even though the front is now elevated by 3" with a supplied bracket. It has to be added to clear the engine and close the hood.
6) Added a $8.00 relay to kill the engine with the key switch and shut off the charging circuit battery drain.

The 18hp B&S power is great. The tractor runs quieter. There is certainly a difference in front-end tractor weight versus the Onan which does allow the tractor to steer easier.

Right now the Onan B43 in sitting in the garage still leaking oil. If anyone is interested in it let me know.

Many thanks to all those who help making this project fun and a positive experience for a novice weekend mechanic.

John