old military engine

Discussion in 'Off-Topic' started by electronis whiz, Jul 26, 2011.

  1. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    we have h machine that has a military 4 cylinder 6 horse gas engine. the person we got the machine from said it has 24 volt starter. there are what look like 2 lawnmower batteries on it and a voltage test shows aprox 5V per battery. so were wondering if the baterys are 6 V per and they jsut usumed they were both 12V batteries. or have the batterys gone bad?
    i am unable to read anything on the starter label becase of it's location. there apears to be a small motor looking thing on the side and then a bigger motor that i beleve is the starter wired in sieries.
    is there any harm in trying to start off a car battery.

    i have looked at manuals for it and they all show starting it using a pull rope wraped around a pully. nothing mentioned about a starter.
    it is stock #nsn-2805-00-068-7512
    any ideas or sugestions apreciated.
     
  2. VoodooMojo

    Active Member

    Nov 28, 2009
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    how many cells does each battery have?

    the little motor thing on the side wired in series with the starter is most likely the starter solenoid.

    if the Starter motor is indeed 24 volt then you will need to put 2 12 volt batteries in series to total the 24 volts.

    be careful....24 volts is not as friendly as 12 volts is.

    Take the starter motor to a electric motor place and have them match it with a 12 volt variety...will save a lot of aggravation

    or use a starter rope...
     
    Last edited: Jul 26, 2011
  3. SgtWookie

    Expert

    Jul 17, 2007
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    Here is the manual for it: http://www.liberatedmanuals.com/TM-9-2805-262-14.pdf

    Almost all military starting systems are 24v, except for the GSA (general services adminstration) fleet.

    You can try using just 1 12v battery, but it won't likely budge it. The starter might click, but that's about it.

    [eta]
    Those types are usually auxiliary engines, made to power accessories on a vehicle. A local Vietnam War museum I've been a member of for years has an Avenger missile system; a HMMVEE with a missile targeting system & missile pods mounted on it. The system rotates around 360°, and you can elevate/lower the missile pods; the whole thing is powered by an aux engine like that one.
     
    Last edited: Jul 26, 2011
  4. JoeJester

    AAC Fanatic!

    Apr 26, 2005
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    Sgt,

    Interesting TM there. Not one mention of a battery as that engine is a pull start.

    To the OP ...

    Is there another NSN associated with that assembly? The NSN you posted was the engine, rated as 6 HP at 3600 rpm.

    On edit ...

    If it is a 3kW generator set, then this technical manual applies ... http://igor.chudov.com/manuals/Military-Generators/MEP-016A/TM-5-6115-271-14.pdf

    That engine, like Sgt said, is used alot of places. I did a google search using tm +"2805-00-068-7512" and found technical manuals for generators and air compressors. The OP would have to post a pic to see what that engine is attached to.
     
    Last edited: Jul 27, 2011
  5. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    that is kind of thinking sould happen with just a 12 v battery.
    the ones that are on it have 6 cells per battery. they are about th size of lawnmower batterys there so old i have nott seen any info on them other than the normal warning label.
    i am no sure what the engine is from originaly. we have it on a bandsaw sawmill.
     
  6. JoeJester

    AAC Fanatic!

    Apr 26, 2005
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    Like Sgt said, they are 24 volt systems. Unfortunately you only had the NSN for the engine. Using it for the bandsaw it appears the air compressor manual might be the closest to your configuration.

    Worst case scenario, gather all the TMs out there and "meld" them into one best suited for your needs.
     
  7. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    i just ran a test on the starter relay and solenaid. i used a 12V charger. conected black to chasis and + to the starter relay coil terminal and the what i beleve is the starter solenoid is also connected to this terminal i heard both making sounds. (and this was off 12volt.)

    here are the other numbers for it
    engine gas
    military standard
    4c-11
    32 cubic inch
    stock # nsn-2805-00-068-7512
    mil model # 4Ao32-II
    manual tm-5-2805-203-14and 24p
    christleroutboard
    made 3-73
    po#DAAk01-74-c-5515

    it also has a rope starter pully on it. if needed how would i use this to start it?
    the curent configuration has 2 series batterys there is an altornator that can charge them 1 at a time. there is a piece of 18-16 AWG wire with quick connects between them. this seems prey small to provide enogh curent to turn over. the other wires are like 6-4 AWG whould i make a heavy jumper wire to conect these instead.
     
  8. JoeJester

    AAC Fanatic!

    Apr 26, 2005
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    All those numbers point to strickly to the engine.

    If it's a military modified for electric start it will be 24V. I would suspect it would use two lawnmower type batteries, but I also would suspect the wire connecting the two batteries in series would be equal to the wires to the engine.
     
  9. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    we got 2 new batteries for it i put a chink of 10 AWG between the batteries. the saw mill has a 12v alternator on it there is a switch connected to the circuit. but it makes no sense because the switch is conected between +,- so when it is tuned on there is a dead short on the altornator. is there a reson it's like this?
    some where i think i r5ead once somthing about some generators, alternators needing load else they will fry or somthing like that is that true?
     
  10. SgtWookie

    Expert

    Jul 17, 2007
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    Alternators/generators need to have a battery connected at all times, otherwise the regulator will have the output overshooting and undershooting the target voltage. It could destroy the regulator itself, and/or any other electronics connected to it.

    When those kind of engines are used as an auxiliary engine, they usually don't have onboard generators/alternators or batteries; that's taken care of by the host vehicle. They frequently do have starter motors though.

    I don't know how your generator/alternator will be able to charge both batteries unless it's designed or re-designed to output 27v-28v. Usually, the frame of the alternator or generator is grounded to whatever it's connected to. The batteries would have to be wired in series for starting, then wired in parallel for charging.
     
  11. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    the alternator is 12V froma junk yard there it can only charge 1 battery at a time originaly they were in series using quick connects and 18 AWG wire. but i swaped it out when replaed the batterys with 1 piece of 10 AWG.
    to charge the one that had it's - to the positeve of the 2nd youdisconected the sires conected to a gnd wire conected an aligator clip to + and the other you just connected the aligator clip.
    i was thining some kind of 3 way switch here. or just get big quick conects or aligator clips.
    i was also just coneidering disconecting the drive belt to the alternator. then just charging them using a charger. there is no lad on these other than the starting system.
     
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