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Onan 12.5JC-3CR/21919AB ser:F800510415 newbie questions


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  #1  
Old 01-04-2018, 08:31:26 PM
gregschultz gregschultz is offline
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Default Onan 12.5JC-3CR/21919AB ser:F800510415 newbie questions

I just got this genset from a friend - it appears to run fine and have been reasonably well maintained. I hope to get a load on it this weekend. But, I have a couple of newbie questions.
1. What other manuals (I downloaded the Master Service Manual) should I need and where should I look to find them (google comes up empty)?
2. It appears that the compression on my engine (JC - 6.5:1) is low for a propane conversion. I expect to run the genset on my land integrated with an "off grid" alternative power system. I was thinking that propane was the easiest fuel to store, transport (I'll just have it delivered) and least expensive. Should I give up on ideas of converting it to propane?
3. I intend to keep the genset outside; would it be best to put it under cover?
4. What other notions should I be considering??
Thanks.
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Old 01-04-2018, 09:05:59 PM
Wayne 440 Wayne 440 is offline
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Default Re: Onan 12.5JC-3CR/21919AB ser:F800510415 newbie questions

(1) The manuals can generally be had for asking nicely and a good email address

(2) The JC will run fine on propane with low compression pistons, and you can still use gasoline as a contingency fuel.

(3) It is "best" to have it in a shed so you can work on it in relative comfort when it fails during bad weather.

(4) Obtain a stock of commonly needed spare parts and filters.
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Old 01-05-2018, 12:11:28 AM
Jim Marcozzi Jim Marcozzi is offline
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Default Re: Onan 12.5JC-3CR/21919AB ser:F800510415 newbie questions

And get a spare voltage regulator. It's not that it may fail....it WILL fail. And will be 3 degrees when it does. Call Flight Systems and get a new one now.
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Old 01-05-2018, 03:50:23 AM
Ray Lynch Ray Lynch is offline
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Default Re: Onan 12.5JC-3CR/21919AB ser:F800510415 newbie questions

Manuals available here.
Ray

http://www.twinslan.net/~n0nas/manuals/onan/
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Old 01-05-2018, 08:15:53 AM
Max Thompson Max Thompson is offline
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Default Re: Onan 12.5JC-3CR/21919AB ser:F800510415 newbie questions

Quote:
Originally Posted by gregschultz View Post
3. I intend to keep the genset outside; would it be best to put it under cover?
4. What other notions should I be considering??
Thanks.
Welcome to The Stak, home of the Green Disease and many infected people.

The JC is a great set, yours is a very desirable one. Full output in single phase 120/240 and a relatively late model. Propane is the fuel of choice, clean burning, stores indefinitely, and you control the source.

Weather protection is a concern, but RODENT protection is just as important. Rodents have ruined as many of these sets as the weather has.
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Old 01-05-2018, 09:55:05 AM
KPack KPack is offline
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Default Re: Onan 12.5JC-3CR/21919AB ser:F800510415 newbie questions

Manuals here also.
http://onan.xmsi.net
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Old 01-06-2018, 11:29:27 AM
gregschultz gregschultz is offline
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Default Re: Onan 12.5JC-3CR/21919AB ser:F800510415 newbie questions

thanks!
gregschultz0177@yahoo.com
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Old 01-06-2018, 04:40:57 PM
gregschultz gregschultz is offline
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Default Re: Onan 12.5JC-3CR/21919AB ser:F800510415 newbie questions

Holy Toldedo!

---------- Post added at 12:40:57 PM ---------- Previous post was at 12:37:20 PM ----------

Ahhhh. So, great point. I figured I could set the genset on a bed of gravel, erect 4 posts and a roof and get on with it. Rodent control (I'm on 20 acres on a recently looged hillside) is going to be a bigger challenge. That will require 4 walls, a door AND a cat. hmmm.
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Old 01-06-2018, 06:09:25 PM
Gunny Gunny is offline
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Default Re: Onan 12.5JC-3CR/21919AB ser:F800510415 newbie questions

I would not set it on gravel. Build a rack out of angle or tubing that will bring the genset 24 to 36" off the ground. Will make it a whole lot easier to work on it and make it a lot less attractive to rodents.

Set the rack on concrete, you don't want this to move.

Roof high enough for you to stand erect without banging your head. Hand some lights so if you need to be working on it in the dark, you can see what u=you are doing without a flashlight in your mouth. Extend to roof far enough so the wind will not blow rain on the machine.

Set it so it gets sunlight to dry things out, if on the north side of a building or wall where it gets no sun, they tend to rust and/or have mold/mildew problems.
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Old 01-06-2018, 07:39:56 PM
Max Thompson Max Thompson is offline
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Default Re: Onan 12.5JC-3CR/21919AB ser:F800510415 newbie questions

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I would not set it on gravel. Build a rack out of angle or tubing that will bring the genset 24 to 36" off the ground. Will make it a whole lot easier to work on it and make it a lot less attractive to rodents.

Set the rack on concrete, you don't want this to move.

Roof high enough for you to stand erect without banging your head. Hand some lights so if you need to be working on it in the dark, you can see what u=you are doing without a flashlight in your mouth. .
All good advice. If you have ever pulled the starter off a J set you will appreciate at least a couple (or more) feet of clearance on the back side, Leon can tell you what a PIA it is to have to lift and turn the set to do this.

12 volt lighting (in addition to 120 volt) will be useful when there is no AC power available.

If you are starting from scratch, you can build it like you want for just a little more.
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Old 01-06-2018, 09:05:21 PM
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Billy J Shafer Billy J Shafer is offline
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Default Re: Onan 12.5JC-3CR/21919AB ser:F800510415 newbie questions

Take the advice Gunny and Max have given you. You will thank yourself for doing so. I have been doing this field of work since 1974. I can't tell you how many times I have spent. Extra time getting things out of the way. Just to do work. When it is 15 with blowing snow and ice and your trying to dig a genset out of the mud. You will be talking funny. Or you are in the bushes trying to avoid the thorns. You will understand why.
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Old 01-06-2018, 11:03:12 PM
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Default Re: Onan 12.5JC-3CR/21919AB ser:F800510415 newbie questions

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Originally Posted by gregschultz View Post
Is your generator set up with the dual fuel, Gasoline or Vapor carburetor?
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