Another Javelin question: starter motor

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This topic contains 20 replies, has 9 voices, and was last updated by Avatar reivertom 8 months, 1 week ago.

Viewing 15 posts - 1 through 15 (of 21 total)
  • Avatar
    nj-boatbuilder57

    Replies: 253
    Topics: 37
    #8664

    The restoration continues!

    This is my first electric start engine, and I am genuinely stunned to measure the starting current at 225A. Measured with a Fluke clamp-on meter and a known-good, strong battery (from my truck; my boat battery won’t turn the engine at all), the data is right there on the meter: 225A.

    This is MUCH higher than a typical car starter, so I have to ask: is this correct? Or is this starter in need of rebuilding / replacing?

    I’ve googled but can’t seem to find a definitive answer. Anyone know for sure?

    Thanks!

    frankr
    frankr
    US Member - 1 Year
    Replies: 4385
    Topics: 43
    #67383

    I don’t know which specific starter you have, but looking at one in random, I see 170 Amps at stall test.

    Avatar
    jeff-register
    US Member - 1 Year
    Replies: 1121
    Topics: 47
    #67384

    I’m with Frank,
    Bad fields or shot bushings. Chevy used paper to insulate the fields, 1 rain & they are wet & decomposing, heavy draw, no magnitisun & less force, Yea I can’t spell. We are talking starters, right

    Avatar
    nj-boatbuilder57

    Replies: 253
    Topics: 37
    #67390

    if LRA = 170A for this size starter, then FLA = 225A seems way wrong.

    Are these specs published somewhere?

    Avatar
    jeff-register
    US Member - 1 Year
    Replies: 1121
    Topics: 47
    #67391

    Na,
    R.L.A.= running amp draw
    F.L.A.=full load amperes & next is locked rotor amps & higher,
    Friction is evident :mrgreen:

    Avatar
    nj-boatbuilder57

    Replies: 253
    Topics: 37
    #67395

    So what’s an appropriate replacement? The OMC part number from ’57 seems to be 376850, which (according to marineengine.com) rolls into several newer numbers, which fan out to dozens of different manufacturers’ offerings, ranging in price from $50 to $200. Sure seems easy to make a purchasing error.

    Any suggestions?

    Avatar
    jerry-ahrens
    US Member - 1 Year
    Replies: 1016
    Topics: 70
    #67397

    The Arco 5376 would be a good choice. I’ve put on a gazillion Arco starters, aternators and power trim motors, etc. never had a bad one. I often turn to them vs. OEM to keep the price down.
    If I remember right, the Arco starter is physically shorter than some of the original OMC starters, but will work fine.

    frankr
    frankr
    US Member - 1 Year
    Replies: 4385
    Topics: 43
    #67399

    As you have discovered, there was a lot of evolution down through the years, and many newer starters will fit older motors. So, we don’t even know if your starter is original to the motor. 1957 was the first year for 12V starters, and the truth is they weren’t all that great. They were just adequate, and were easily damaged by stalling them or cranking for extended time.

    I am presuming you may have the MDO which is where I got the 170 figure. But look at the difference between MCO and MDW specs. The MDW draws fewer amps but has considerably more ft/lbs of torque. Sorry, I don’t have a chart for newer models.

    frankr
    frankr
    US Member - 1 Year
    Replies: 4385
    Topics: 43
    #67400

    BTW, note that the specs are for 10 running Volts at the starter (4 V stall). In theory, at least, if you are supplying more voltage, like 11 V or more, the Amperage would go higher.

    Mumbles
    Mumbles
    Canada Member - 2 Years
    Replies: 4183
    Topics: 424
    #67407

    Before shelling out for a new starter, why not remove the lower end cap and check the condition of the lower thrust washer? If it is badly worn or missing, it will allow the armature to drop causing the commutator segments to short out to the end cap. Symptoms of this are a dragging starter and high current draw.

    Avatar
    nj-boatbuilder57

    Replies: 253
    Topics: 37
    #67409

    Great info!

    This page is not in my service manual…..I’m sure glad to have it. Thanks!

    Avatar
    billy-j

    Replies: 88
    Topics: 8
    #67419

    Mumbles said. Before shelling out for a new starter, why not remove the lower end cap and check the condition of the lower thrust washer? If it is badly worn or missing, it will allow the armature to drop causing the commutator segments to short out to the end cap. Symptoms of this are a dragging starter and high current draw. I agree with Mumbles you can not expect a 60 year old starter to work as new. A 1956 starter is very simple to take apart. Make some match marks on the housing and end cap and take it apart. It might just need to be cleaned up and the bearings lubricated and brushes cleaned up or replaced.

    Avatar
    billy-j

    Replies: 88
    Topics: 8
    #67420

    Mumbles said. Before shelling out for a new starter, why not remove the lower end cap and check the condition of the lower thrust washer? If it is badly worn or missing, it will allow the armature to drop causing the commutator segments to short out to the end cap. Symptoms of this are a dragging starter and high current draw. I agree with Mumbles you can not expect a 60 year old starter to work as new. A 1956 starter is very simple to take apart. Make some match marks on the housing and end cap and take it apart. It might just need to be cleaned up and the bearings lubricated and brushes cleaned up or replaced. regards Bill,

    Avatar
    nj-boatbuilder57

    Replies: 253
    Topics: 37
    #68700

    Hey guys,

    Just thought I’d circle back on this with an update.

    I disassembled the old starter, and while nothing looked "wrong", everything looked old & dirty & worn. I took the armature to work and meggered the windings, and the results were "meh" at best.

    So I bought a new motor, and…SHAZAM!!…instant success! My clamp-on is at work, so I can’t tell you what the starting FLA is, but I can tell you that my boat battery (which I had suspected to be tired, as it wouldn’t turn over the engine with the old starter at all) has no trouble at all turning the motor over with ease. So I’m certain the FLA is *WAY* below that of the old motor. I’ll measure it next week when I can bring my meter home.

    Thanks for the help. Greatly appreciated.

    Avatar
    rjoynt
    US Member - 1 Year
    Replies: 138
    Topics: 25
    #68701

    What did you end up buying? Price?

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