Fuel Solenoid Power ??
 

SO I put a new carb on my 3206 with Kohler CH22S today. I found the PO had removed the solenoid and placed a blank steel strip over the hole.

The wire was still there so I simply plugged the new solenoid into this wire. However, the engine would start but then shut down a second later.

I found that the solenoid is only energized while the key is tuned fully to start. As soon as the key is released the wire is dead again.

Am I correct that as long as the key is on the solenoid should be energized then when key is off the solenoid is de-energized and shuts fuel off ? Right ?

The fuse in the fuse block with red wires is hot on both sides.

Any ideas why this solenoid wire goes dead with key in run position ?

You are correct.

There several interlock (or safety) devices in the circuit.

There are 3 different wiring diagrams for the 3206, depending on Chassis Serial Number. Let us know the S/N and I'll trace down the diagram in the morning.

Great ! Thanks ! here's the info...

There are 2 diodes in that circuit that power the solenoid. One is in the start circuit and the other in the run circuit. The violet wire from the alternator should go to a junction with the red wire going to the fuel solenoid for the run circuit. I'm thinking your "run" diode is open. You will need to check that with a diode check function on a meter.

Hey oak, if that's the case then I should read 12 volts (with key in run position) at the engine connector where the red and violet wires connect together or, the red wire on the opposite side of that connect right ?

In other words, before the diode.

Yes. Here is some diagrams that will help.

With the engine not running and the key in the run position the seat safety switch must be closed(sitting in seat). With the engine running the alternator will power the solenoid and the seat switch is out of the circuit.

Todd:

I spent a couple of hours looking this morning, to see if Cub Cadet or Kohler had a Diode Replacement. Best I could find, but could not verify, the diode(s) are part of a Kohler harness - #24-176-171-S. Seen it was a bit pricey. I could not find a good picture of that kit, to see what it included. One could buy a single Diode from some supplier for <$5.00 ...... IF.....one knew the specifications.

:Work:

Did a quick search and found a diode replacement kit- 25 755 31-S.

I know how I would fix it..... and it wouldn't involve diodes. :biggrin2:

But I can't say on here what I would do......

Hey guys, all good now !! Stuck test light into engine connector at red/violet, turned key to run then started checking. Got to the seat switch connector, as you referred to Todd and as I knew, it was disconnected by PO. I never worried about it since the engine ran. It of course ran because as I said above, the PO had removed the fuel solenoid.

Then I looked at the schematic and saw it's a N/O switch. Corrected that safety switch connection and...test light lit up ! Yahoo !!. I then placed test light into solenoid connector and lit up. So that diode is obviously not open. I do a good bit of electronics work as one of many hobbies and have a few organizer drawers of diodes of various sizes and ratings. And YES, $5 is pricey !!

So put everything back together and it fired right up and ran absolutely great in all throttle positions and idles low, smooth and quietly. VERY happy.

Thanks for all the help guys ! I really appreciate it,

Steve

It's not always easy figuring out what a PO did or why. In this case it seems the PO just didn't know how to test these things. Glad ya got it worked out:beerchug:

Very true ! I've found and repaired several things he did and I can only assume he either wasn't good with mechanical things or just a hacker upper and didn't care. That really drives me crazy when guys don't appreciate and take care of machines and repair them correctly, at least within reason.

Parts were missing I figure because someone was just too lazy to put them back on. I've ordered new and good used ones and replaced them.

***OR***
It could be that the original solenoid failed, and he simply removed it as it isn't a required part. Not really necessary either. The seat switch may have been unhooked because he hated all the safety devices. Personally, I only keep a few safety devices on my machines, if any at all.

Well I understand that and mostly agree, to a point. Some things I referred to were things such as an engine side cover panel missing, the dash/battery baffle missing, the rear deck rollers missing, the crankcase breather tube disconnected ! And some other things done that looked like someone was very frustrated. But... I got it for a good price and I'm not so much complaining, just don't understand why some things are done the way they are.

And you'll notice I didn't say I re connected the seat switch, I hate all these types of things caused by idiots and lawyers. The only safety left on this CC is the brake safety switch. Which is OK.

And if the fuel solenoid will help stop or reduce backfires and dieseling when shutting down, then for me it's worth having it in place.

On my previous JD, it had so many silly safety interlocks I completely removed the wiring harness and neatly re wired only so the engine would start and the lights worked. So much better for me. I did this right after I bought it new.

I know how I would fix it..... and it wouldn't involve diodes

I hear ya there J... : -)

A 1N5408 rectifier diode should be able to handle it - maybe a little overkill. I just got some for a different project, they were $ 0.26 each. The 1N5408's are rated for 3A forward current and have a peak inverse voltage rating of 1000 volts.

Frank:

Thanks, good information.

:IH Trusted Hand:

I don't have an issue with the fuel solenoid. I removed it from my 3205 with the Kawasaki engine and it does backfire sometimes when I shut it down. Now I wish I hadn't removed it (ground the tip off of it). I say, install the 30 cent part and be good for another 20 years.

I have 2 Kohler CH's and 3 Vanguards, I have ZERO working Fuel Solenoids. :biggrin2::beerchug:

IIRR
Fuel sol's, came about to comply with emissions.
When the engine ignition is terminated, the rundown allows a bit of fuel/air through the engine, producing unwanted emissions.
Every tiny bit gets measured and it is a way to comply.
An added benefit is a reduction in dieseling and ignition of unused fuel in the exhaust system.

FWIW If a person is experiencing a back fire or "pop" in the exhaust after shutting off the ignition, sometimes it is caused by introduction of air into the exhaust system.
Example: loose clamps, gaps between pipes/mufflers, or deteriorating system
(rust out)
A good exhaust system helps eliminate that.:bigthink:

All good info from everyone !

After running and mowing a couple hours in 90* heat, I shut down and for the first time since I brought it home there was no backfire or dieseling.

Now I suppose some of that may have possibly been caused by the old carb and the fact that I found the PO had torn a section of gasket off and not replaced with a new one between the top of the carb and the air cleaner plate. Although I doubt that would make a differnce.

So I agree with you Todd, why not keep the Fuel Solenoid. I know they run without it but I really hated the backfires, etc.

I'm so happy with how great it runs now with the new carb and gaskets !! Definitely MUCH smoother and more power.

Note that I also ran all new fuel line, a new large fuel filter and added an electric fuel pump. I'm sure the mechanical pump was failing as I found bits of rubber in the fuel filter between the pump and carb. I of course had a filter before the pump as usual also.

I have another question, as you know, the air cleaner base plate has 4 triangular openings. 2 of these line up with the blower ducts and the other 2 take air in from above the engine.

Seems it would be better to close off the 2 over the engine and just intake relatively cooler, cleaner air from the blower.

Anyone done this ? Any thoughts ?

The purpose of the holes above the engine is to let out the excess air, and blow out extra dirt, from the filter housing. If you plug them off, you will create a problem. They need to be there. The fan pushes more air into the filter housing than the engine can use.... for good reason.

Ahh !! good points ! I didn't think of it that way. And, might over pressure and cause problems with the carb.

Great info, thank you ! I'm glad I asked first.

I want to add, before anyone goes thinking it, that you can't "supercharge" the engine with the cooling fan. Yes, there is a very low amount of positive air pressure in the blower housing, plugging the holes will divert the air to the engine cooling. Basically, it will just stop flushing the excess dirt from the filter housing. You'll take the air filter cover off and find it packed with grass/leaves and debris. No, it won't "force feed" the carb.... very much. It may throw the carb adjustment off, but no more than if you tune it without an air filter, then put the filter on.

Well maybe we can add that aspect of 'supercharging" along with the Oil Pump idea to a K series engine and have a real grass cutting machine!!

Lol. Maybe the charge air would add enough power to drive the oil pump. :biggrin2:

That’s an outstanding idea :ROTF1:

Every once in a while I come up with a good idea.... : -)

May as well go all the way to stupid. :biggrin2:

https://www.youtube.com/watch?v=8LXFSLK3otM

He could have at least put a 54 inch deck on it!!!!

I have a question, on a QL it has the same type of air intake, where is the hole to let out the leaves?

I wondered when someone would ask that.....
The QL was set up the same way, but they didn't put any holes in it to flush the dirt out. I do believe if you look though, the filter cap doesn't seat tight to the back. It can flush some dirt out. For the most part, the idea is the rotary screen on the flywheel will stop the big stuff, but we all know grass can still get through. Sometimes engineers get stuff right when they redesign. I like the later air filter base that can move air through it to help flush out debris.