Farm Equipment - Manifold pre-heater

Manifold pre-heater

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Category: Allis Chalmers
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URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=135501
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Topic: Manifold pre-heater

Posted By: AC6080MAINE
Subject: Manifold pre-heater
Date Posted: 25 Feb 2017 at 3:11pm

Hey guys i have had some trouble getting the tractor started without plugging it in so i wanted to check and make sure that my manifold heaters are working correctly.

I pulled them today, one broke during the process so that will need to be replaced. I ran some tests to see what numbers the solenoid was putting out but i need your help trying to figure out what they mean.

I'm assuming these things work like a spark plug; they need positive from the solenoid and ground themselves out in the manifold hole?

I detached one of the cables to check ohms against ground. With the key off i had 2.0 ohms. With the key in the on position i had 4.6. When i press the manifold heater button, it jumps off the chart. Does this mean that my system is working correctly? When i pulled a heater plug to check and see if it was getting hot i forgot to ground it, so at the time i thought it wasn't working but now i'm thinking its like a spark plug and needed ground. Can someone tell me if the ohms and operation look correct?

I would go back out and check the heater plug with ground but i'm already cleaned up, the solenoid is off the tractor, and i need my wife to push the manifold button.

Like i said one of heater plug ends broke on removal so i will have to replace that one, is it worth replacing the solenoid with an aftermarket for $25? Everything was about as dirty as could be so i have been cleaning up my contacts but the solenoid itself is pretty filthy and corroded. Wont get to call for parts until monday, anyone have an idea how much money the heater plugs are?

Thank you i appreciate it.

Replies:

Posted By: jaybmiller
Date Posted: 25 Feb 2017 at 3:20pm

These heaters are just low value resistors. I have one on my forklift...
yes, gotta be grounded to work.
At 2 ohms, it'd draw about 6 amps. ( 12V/2=6).
You can't measure OHMS when you supply it with 12 volts,explains why the meter went 'funny'.
I'd press the button, wait 60 seconds,hop off and LIGHLTY test the manifold for heat near the glowplug. It should be warm to HOT. The ammeter will go 'discharge' maybe 10 amps or more(depends on # of working glowplugs).

Jay

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3 D-14s,A-C forklift, B-112
Kubota BX23S lil' TOOT( The Other Orange Tractor)

Never burn your bridges, unless you can walk on water

Posted By: JC-WI
Date Posted: 25 Feb 2017 at 4:43pm

Is this the 6080 you have in your name or some other model?

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He who says there is no evil has already deceived himself
The truth is the truth, sugar coated or not. Trawler II says, "Remember that."

Posted By: AC6080MAINE
Date Posted: 25 Feb 2017 at 9:09pm

Yes sir, a 1983 6080. I can set the plug down where it gets ground and see if the coil heats up.