Bad coil keeping genset from starting?

softdown
softdown Solar Expert Posts: 3,897 ✭✭✭✭
in Off Grid Solar & Battery Systems #1
Off grid gensets are constantly dying. Constantly. I usually have no less than two gensets at the repair guys place. I let him fix them at his leisure and he gives me a discount. Still....the expenses add up and hauling gensets around is not fun.

The Onan Homesite 3500 worked pretty good until the day that I found roof water dripping on it. Trying to maintain it, I immediately tried to start it. No life whatsoever.

Thought some dirt got in the switch. Tore it apart some. Switch is clean. Put a screwdriver in the coil output. Weak shock that I can feel but it is weak. The voltmeter in my body (developed after dozens of shocks) tells me the coil is putting out about 6 volts or so.

Starter fluid doesn't help at all. It is like the unit is just....dead.

Haven't really been a wrench monkey since the 70's but I seem to recall 10,000 volt Mallory coils. So "6 volts" seems pretty anemic.

It has delivered approx 55 volts a couple times. Wriggling the starter switch wires "fixed" the output. But the switch connections seem to be alright. I could very easily replace the switch at this time....if I could find the switch for sale.

Bad coil? Weak coil? Common problem? Am I stupid and better off taking it to the genset repair guy?

TL;Dr - coil spark hardly shocks me at all when pulling on starter rope. Bad coil?
First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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Comments

  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #2
    Re: Bad coil keeping genset from starting?

    Sure sounds like it...change the plug while you're at it.

    Drain fuel and replace, use some SeaFoam http://seafoamsales.com/sea-foam-motor-treatment/ stabilizer or equivalent...
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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  • softdown
    softdown Solar Expert Posts: 3,897 ✭✭✭✭
    #3
    Re: Bad coil keeping genset from starting?

    Thanks for the re-assurance. Sea-foam has such a cool name that I bought six bottles. PRI-G and PRI-D are very good gas stabilizers that I use. Now that we are sending troops to the Ukraine...I am back to prepping a bit. :roll: War with Russia will surely have a happy ending!
    westbranch wrote: »
    Sure sounds like it...change the plug while you're at it.

    Drain fuel and replace, use some SeaFoam http://seafoamsales.com/sea-foam-motor-treatment/ stabilizer or equivalent...
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #4
    Re: Bad coil keeping genset from starting?

    Are you 100% sure that the low oil pressure or level cutoff is not messing with the ignition system?
    SMA SB 3000, old BP panels.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #5
    Re: Bad coil keeping genset from starting?

    The coil assembly on EBay seems to be around $16:

    Attachment not found.

    This may be the manual?:

    http://www.cumminsonan.com/www/pdf/manuals/914-0500.pdf

    Do not see any points/CDI...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    #6
    Re: Bad coil keeping genset from starting?
    Are you 100% sure that the low oil pressure or level cutoff is not messing with the ignition system?

    I unpluged mine today for the very reason that it ran and then would not start again and the generator is full of oil.
    gww
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  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    #7
    Re: Bad coil keeping genset from starting?
    gww1 wrote: »
    I unpluged mine today for the very reason that it ran and then would not start again and the generator is full of oil.
    gww
    When you say that the generator is full of oil, do you mean the engine (good) or the generator head (very bad.) :D
    SMA SB 3000, old BP panels.
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #8
    Re: Bad coil keeping genset from starting?

    The oil sensor in my 3600rpm screamer never worked right, so I just unplugged it. it grounds the spark coil.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    #9
    Re: Bad coil keeping genset from starting?
    When you say that the generator is full of oil, do you mean the engine (good) or the generator head (very bad.)
    Luckly it was the "GOOD" situation. One point to this is the ease of checking. Unplug-starts-bad senser. Not a bad test to perform.
    gww
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  • softdown
    softdown Solar Expert Posts: 3,897 ✭✭✭✭
    #10
    Re: Bad coil keeping genset from starting?

    Checked the oil level a couple times. It is a little bit overfull from the last owner. Good suggestion though. Edit: Found a wire that is likely the low oil level cut off thingie. Disconnecting it did nothing.
    inetdog wrote: »
    Are you 100% sure that the low oil pressure or level cutoff is not messing with the ignition system?
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • softdown
    softdown Solar Expert Posts: 3,897 ✭✭✭✭
    #11
    Re: Bad coil keeping genset from starting?

    Ordered a coil. Looking at the Onan manual that BB was kind enough to dig up....looks like replacing the coil might become a can of worms.... p.31 of repair manual. I have never learned to do serious work on gensets since I have a repair guy that treats me fairly.

    Thinking it may be best to give the coil and genset to him. Things are 100 times easier when you have done it 100 times.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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