Early 2082 with CH-18 fuel solenoid

[FrankF3]

Not knowing what diode was used originally, I would think a 1N4004 would suffice. This is capable of 1 Amp average rectified output current, with a peak repetitive reverse voltage of 400V. I wouldn't think any voltage spikes from the solenoid would exceed 400V.

[J-Mech]

Originally Posted by ken746

That engine runs leaner, which means hotter than your old Mag. I believe that solenoid is there mainly to prevent backfire when you shut down. I would keep it working and get the diodes.

Huh.... because the solenoid is wired directly to the alternator. The solenoid doesn't shut until the engine stops turning completely. So.... it can't really prevent backfire if it's open until the motor stops. I don't even know why there are on there except maybe to keep fuel from leaking into the motor if the needle valve fails or if it is in an application with the fuel tank higher than the motor. Unnecessary part IMHO.

[Sam Mac]

Just a FYI not all engines come with the solenoid. While all the CH's and Vanguards that I've seen as originally installed in Cubs have had the solenoid I bought a new in the box Vanguard for a 1641 and it has a plug in the carb where the solenoid goes.

[Sam Mac]

This is from the Kohler CH service manual.

Fuel Shut-Off Solenoid
Most carburetors are equipped with a fuel shut-off solenoid. Solenoid is attached to fuel bowl. Solenoid has a springloaded
pin that retracts when 12 volts is applied to lead, allowing fuel flow to main jet. When current is removed, pin
extends blocking fuel flow.

Key words :Most carburetors are equipped with a fuel shut-off solenoid.

I read this to mean that not all have the solenoid.

[Mike McKown]

I have one Command that doesn't shut down right away when I turn the key off.
It just keeps idling smoothly for maybe three seconds and then dies. That tells me the ground for the mags isn't working for some reason but the solenoid is. The engine is just burning out the remaining fuel. At one time, this engine was running pretty hot but I took care of that. When it was running hot, it would continue to run (diesel) after the key was shut off and then kick backwards and stop.

3-4 other Commands shut down immediately when the key is turned off.

One of these Commands WILL NOT START when the battery is just slightly low on voltage without priming the carb. Prime the carb with a shot of brake cleaner and it fires off instantly and runs smooth. I suspect the lower than ideal voltage for some reason isn't enough to energize the solenoid during cranking. If you hook a charger to it for a couple minutes fefore cranking it will kick right off without priming.

One of these day if it gets to bothering me, I'll check it out and find out for sure what's up.

As far as the "anti-backfire" thing. Kohler and Briggs might have put them on the engines to stop fuel from percolating (due to heat) and forcing gasoline fumes into the muffler which can cause a backfire on the next start up.

[PeterJ]

Originally Posted by Mike McKown

I have one Command that doesn't shut down right away when I turn the key off.
.

I think you should check the heads for excessive carbon build up.

I hope that helps.

PeterJ

[WF PhD]

I've cut the plunger out on two Commands without issue. One less electrical thing to go wrong.

[Mike McKown]

Originally Posted by PeterJ

I think you should check the heads for excessive carbon build up.

I hope that helps.

PeterJ

Thanks but the engine continues to fire off the ignition after I turn the key off, not hot carbon spots. I wasn't very clear there.

[gt383mag]

ok update. went to radio shack and got some diodes to wire in.wired them the way i thought they should be engine started ran about 10 to 15 seconds and then the starter kicked in. so i assume i put them in backwards so i wired in the other 2 diodes i got when i got the first ones(figured i might need them lol) same thing after ten or so seconds and this time the diodes popped. so i figured ill cut the nub off the solenoid. i took off the air cleaner and heres a wire connector next to carb. hum? do you suppose this is where the wire is supposed to be hooked up? when we pulled the motor out of the donor tractor the solenoid wire was wired into harness elsewhere so i just hooked it up to a live wire when key on. so i hooked solenoid wire up to the connector and ta da problem solved. i wonder why PO wired it like it was? seems to work just fine hooked back up just thought i would share