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What does carburetor solenoid do?

Posted: Tue Mar 10, 2015 8:13 am
by kbrothers
Finally got warm enough for a certain senior citizen to risk going out to check out his 2082. Pulled of carb for cleaning/rebuild Never noticed the electric wire before and my 1882 doesn't have one See solenoids listed in parts diagram Just what is the purpose Thanks and have a good day all! ken in Pa Off to TSC and Cub parts man

Re: What does carburetor solenoid do?

Posted: Tue Mar 10, 2015 9:31 am
by Tom Scott
Ken - That should be a fuel shut-off solenoid. Wire should be hot with key on which opens solenoid and allows fuel to flow. This means that the solenoid is "NC" (normally closed), and will not let fuel flow unless it is energized and working properly.

I like the idea of a fuel solenoid, especially if the tank can siphon into the carb, like on 72 series (1872, 982, 1811, etc.). We ask more from the needle and seat on OPE than a traditional automotive application. In a car, the fuel tank is generally well below the carb and you would never know if the needle and seat is leaking slightly.

I have purchased an external mounted fuel solenoid for the 1872 for this reason. Engine runs great, just every now and then carb will drip gas into the engine. Not severe enough to need a rebuild if I have a fuel shut off. I have been shutting off manually, but that is growing old.

Re: What does carburetor solenoid do?

Posted: Wed Mar 11, 2015 4:06 pm
by kbrothers
Tom I never noticed it on the tractor and when I looked the 1882 didn't have one. I noticed looking up carburetors there was a difference between the hi and lo serial number breks on the 2082 one with solenoid and others without it Ken in Pa

Re: What does carburetor solenoid do?

Posted: Fri Mar 13, 2015 10:50 am
by VScott
Tom brings up some good points, but The main reason that it is there is to prevent backfiring when the engine is shut off. Against everything I had ever learned, if an engine has this solenoid, it should be turned off at half throttle or above so the remaining fuel can be blown thru the cylinders and exhaust.

Re: What does carburetor solenoid do?

Posted: Fri Mar 13, 2015 11:51 am
by Jlaws
Vinny , I don't own any cubs new enough to have a electric fuel shutoff valve . :lol:

With that said , I find it interesting about the half throttle or above at shutdown on the newer engines .

The old single cylinder K series Kohlers , and some of my newer KT's and Magnum twins are bad for backfiring when hot if they are not throttled down for a short time before shutting them down .

My Magnum powered 1535 does it sometimes and it still scares the heck out of me when it happens . :lol:

Re: What does carburetor solenoid do?

Posted: Fri Mar 13, 2015 1:47 pm
by VScott
Jess, that is all that I can find lately. I think I have bought and sold all of the older ones in 5 counties..

My 1535 does the same thing as far as backfiring. It also takes forever for it to stop spinning after it is shut off.

Ken, it is hard to say where they started using the solenoid. My 2082 does not have one but I have an 1862 that does have it. I had a Simplicity that had one as well. I think its a poor design how they have it held in with the spring clip, and I have had nothing but problems with the carbs with this solenoid. You can pull the plunger out and disable it, but you have to leave the body in place, or plug the hole.

The commands all have a similar solenoid, and it will keep one from running when the port gets plugged up.

Re: What does carburetor solenoid do?

Posted: Fri Mar 13, 2015 3:30 pm
by Jlaws
Jess, that is all that I can find lately. I think I have bought and sold all of the older ones in 5 counties..
Vinny , I know what you mean , I was thinking the same exact thing yesterday and even thought of casually mentioning that fact in a shooting the breeze post .

I'm not finding near as many older cubs ( narrow or wideframes ) around my area as I did even 5 years ago .
I think its a combination of them getting parted , scrapped or used for pulling . I used to trip over them around here and now its rare when I see one . I've even noticed a slight slowdown of older complete cubs for sale on ebay and craigslist .

Ken , sorry didn't mean to steal your thread . :oops:

Re: What does carburetor solenoid do?

Posted: Fri Mar 13, 2015 4:18 pm
by JMotuzick
jess
is the slow down due to the winter months?
I've noted the same but figure in a bout a month it will pick back up, there is still 2-3 feet of snow in front of my shed! i'm guessing thats the case in all of the craigslist sections i search...

Re: What does carburetor solenoid do?

Posted: Fri Mar 13, 2015 5:30 pm
by JMotuzick
fyi
i just looked at my records, yes, i'm keeping s/n and model number records now... in the past 26 months i've bought 2 and 1/2 times as many IH cubs as 82 seres and newer. The 82 series normally get fixed the cyclops normally get parted and the IH units are all about how good or bad they are, if they where garage/barn kept they get fixed but if they sat out unused for years they seam to be parts.... I fix when I can, but it's hard when they need a lot of parts to bring them back.

Re: What does carburetor solenoid do?

Posted: Sat Mar 14, 2015 8:32 am
by Farmallgray
It is correc that engines with the solenoid should be shut down at half throttle. I will add that you still want to throttle the engine down to idle for a minute or so to cool it off, then increase to half throttle before shutting the ignition off.

Re: What does carburetor solenoid do?

Posted: Tue Mar 24, 2015 5:02 pm
by bbaker
Anyone ever pull the solenoid and plug the hole?

I've got a couple carbs here I've been thinking about experimenting with.

Re: What does carburetor solenoid do?

Posted: Thu Mar 26, 2015 10:30 am
by VScott
Done it on a Kawasaki vert. shaft engine on a walk behind, and a Deutz Allis with a magnum 18 with good success, but I tried it on a Command in an 1864 and it seemed like the engine took forever to shut off. I removed the plunger but left the solenoid in place on all but the magnum. On the magnum I filled the hole with jb weld. The Command was on an 1864 that I got last summer that is in need of head gaskets, so I can't say that the missing plunger is the only culprit as the engine was running so badly to begin with. I have not had time to get back into this one.

As a side note, and mixing apples with oranges, the vanguards take forever to shut down if the ignition grounding wire becomes disconnected. The fuel solenoid will shut it down but only after several seconds.

I may have a bad wire or switch on the 1864 causing this problem. I would remove the plunger rather than plugging the hole just in case you would want to go back to stock, and you will have the backfiring concern which is hard on an already weak link...the head gaskets.

Re: What does carburetor solenoid do?

Posted: Thu Mar 26, 2015 11:37 am
by bbaker
That's what I was thinking was JB weld the hole up on the Mag carbs! :)

Re: What does carburetor solenoid do?

Posted: Thu Mar 26, 2015 1:01 pm
by Jlaws
I've never used JB weld on anything fuel related , carbs , gas tanks , etc .

I've had a couple of narrow frame fuel tanks that previous owners have used JB weld on , usually around a leaky fuel tank shutoff valve or small pinholes in the bottom of the tank and they all leaked . I've seen where JB weld patches have become soft and separated from fuel tanks . Am I wrong to think JB and gas is a bad combination ?

In fairness the gas we get around here has ethanol in it , and that stuff eats everything after a while , including rubber hoses .....LOL

Re: What does carburetor solenoid do?

Posted: Thu Mar 26, 2015 2:15 pm
by bbaker
Jess, that has always been my concern as well. I do have a product called Devcon that may or may not hold up better? I am tempted to try it as I have a fuel carbs with the solenoid hole.

Re: What does carburetor solenoid do?

Posted: Thu Mar 26, 2015 7:58 pm
by VScott
The rear tank on my truck has a jb weld patch over a stainless sheetmetal screw that has been on there for about 8 years. The Deutz Allis mag 18 has been plugged since 2009.

Not sayin I'm proud of the truck repair (actually ashamed, but at 334,000 miles you do what you have to to hold em together).

Anybody up for a JB weld thread? I have done some pretty miraculous stuff with it!

Also, Bryan....are you looking to get rid of the solenoid totally for a cleaner look or special application or just to eliminate it. Seems to me that removing the plunger from the solenoid allows the o ring to seal, it would just be "faked out". Nothing wrong with them when they are in working order.