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Starter motor amps

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    Posted: 16 May 2020 at 5:00pm
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Anybody know how many amps are drawn by starter motor on a 115hp Johnson Ocean Pro
Cheers
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Post Options Post Options   Likes (0) Likes(0)   Quote Steps Quote  Post ReplyReply Direct Link To This Post Posted: 17 May 2020 at 9:12am
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Titanium
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On a 500cca 60ahr  battery
No load 30amps max 
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Post Options Post Options   Likes (0) Likes(0)   Quote Ad Astra Quote  Post ReplyReply Direct Link To This Post Posted: 17 May 2020 at 12:29pm
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Hi Steps. Hi guess that means its higher on a 680cca/78ah?
But what I'm looking for is ball park eg above ***amps & below***amps when starting boat sitting in the water.
Any clues?
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Post Options Post Options   Likes (0) Likes(0)   Quote Motorhead Quote  Post ReplyReply Direct Link To This Post Posted: 17 May 2020 at 1:51pm
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Originally posted by Ad Astra Ad Astra wrote:

Hi Steps. Hi guess that means its higher on a 680cca/78ah?
But what I'm looking for is ball park eg above ***amps & below***amps when starting boat sitting in the water.
Any clues?


Starter draw while winding your motor over will be around 100-120amps provided minimum resistance is maintained in connections.
Initial inrush current will be about 250amps.

Are you replacing the battery?
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Post Options Post Options   Likes (0) Likes(0)   Quote Ad Astra Quote  Post ReplyReply Direct Link To This Post Posted: 17 May 2020 at 2:00pm
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Thank you Motorhead.
Just what I wanted to hear
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Post Options Post Options   Likes (0) Likes(0)   Quote Steps Quote  Post ReplyReply Direct Link To This Post Posted: 18 May 2020 at 9:08am
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Titanium
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Hi Steps. Hi guess that means its higher on a 680cca/78ah?

 
No.. the current draw comes from the load .. the starter motor requirement. ie total power.. watts needed to turn.
If battery is too small the voltage will drop to maintain the required watts...   V X A = W
So lets say u draw 30Amps @ 12V = 360W  but battery bit small to draw that much, volts will drop excessive, say 10V, still need 360W so amp drawn will be higher @36 amps.
Larger battery no change in volts so no change anywhere..

What will change if larger than 500cca 60ahr  battery, is the voltage drop at the battery by only 1 or 2 points smaller.. which is insignificant.

Starter draw while winding your motor over will be around 100-120amps provided minimum resistance is maintained in connections.
Initial inrush current will be about 250amps.

 
That will be loaded...not mentioned in the service/ repair manual...
 Bench testing .. or as per  service repair manual with plugs out.
 As post above.
most ammeters only read 10 amps, higher end read up around 50/80 amps

 And initial "rush".. if have a ammeter able to measure fast enough will be far higher..ie a SB chevy will hit around 1100 amps for the 1st few milli seconds... under load

 For general home workshop where dont have high load ammeters.
 Bench test .. floor is better.
Connect battery and by pass the solenoid connection.. the motor should spin up clean, no vibrations (ie worn bearings etc)
Then connect to the solenoid only and that should throw out good and solid.
 Then the 2 together , solid smooth spin
99 times out of a 100 it will be good.

Only things that go wrong.
 1/ bearings.. armature not running centered, is weak excessive vibration, but not always
2. brushes worn out
3/ the area the brushes run on need a good clean.. and so will everything else.
4/ The main solenoid copper contacts have eventually burnt away inside.. some solenoids these can be turned 90 degs and good to go again.
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Post Options Post Options   Likes (0) Likes(0)   Quote Ad Astra Quote  Post ReplyReply Direct Link To This Post Posted: 18 May 2020 at 10:18am
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Thanks again Steps. You are a mind of information
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