Starter wiring problem or something else?

AntonNZ

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Jul 13, 2019
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7
Hi everyone!

Have got relatively new 40hp 2stroke outboard.

Took the boat out two weeks ago, everything was perfectly fine. Came back home, plugged the hose, washed the salt off and out. Disconnected the battery. Done.
Took it out yesterday, didn't start. The starter engaged the flywheel but cranked it extra slow with some squeaky sound. Tried the battery from the car - same.
Returned. Checked the voltage with multimeter - 12,6v. Disconnected the starter wire. Turned the key on - solenoid clicked. Checked the voltage at the solenoid - 12,6v. Checked the voltage at the starter wire - 10v when cranks.
Took the starter off for a bench test. Spins perfect, small gear rises up.


What do you think?
 

Chris1956

Supreme Mariner
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Mar 25, 2004
Messages
27,036
Well, your starter sounds fine, as your electrical tests seem to indicate it is good Can you pull the motor over with a rope or pull start? It sounds like the motor is binding or the gearcase is binding.
 

AntonNZ

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Jul 13, 2019
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7
Hi Chris,

Thanks for your response. Yes, I can turn the flywheel with my hand or rope. I'm concerned about low voltage output at the positive starter wire. Why does it drop to 10v?
I tested my battery for CCA and it showed 470 from 550. Can it be any other relay or ground connection or short circuit..?
​​​​​​ I will clean all contacts and try again. Also want to try to bypass the system and start the starter from the car with jump leads.
Any suggestions will be appreciated
 

AntonNZ

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Jul 13, 2019
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Cleaned the contacts. Installed the starter back. Tried to start it connecting straight to the battery, then to the car. Spins extra slow.
Started the outboard with the rope, everything works fine apart from the starter. Whant to try to disconnect the starter and crank it to see the speed. If slow with no load then it might be the starter. If spins fast then it can be some wiring/solenoid/relay issue.
what do you think?
 

Chris1956

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Mar 25, 2004
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27,036
Normally a starter cranking a motor will have a voltage of not less than 8.5VDC, if everything is good.

Since you are getting slow cranking, and the motor is not binding, maybe your starter windings are partially open? It's a guess.
 

AntonNZ

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Jul 13, 2019
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Yeah, may be. I noticed some smoke from the starter when under the flywheel's load. Not much.
when did the bench test - Bendix went up, spined and then went down. Not sure if this is normal.
Do you think it can be fixed or better to get another starter?
 

Chris1956

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I do not know how your starter is wound, so I cannot advise on how to test it. You could disassemble it and take it to a automotive starter/alternator shop (if they still exist), and see if they will test it for you.

I would price an aftermarket starter from ARCO or Sierra and see if it is worth the time and effort to get yours tested. The starter shop will want to fix it as well, which may not be cost effective.
 

AntonNZ

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Jul 13, 2019
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Took the starter out and apart. Black inside, smelled burned, couldn't see any copper parts at all. Cleaned everything, sanded the commutator. There was something like a gasket between the brushes and the bottom lid of the starter body. Brush' wires welded to that lid, maybe that caused the short circuit, I'm not sure. Anyway, I cut the gasket from plastic dense film and inserted between that lid and brushes.
Installed the starter back, started cranking the engine!!!

After 5 continues times (5-6 second each) engine didn't start, but was cranking. Then starter started to do exactly the same thing as before cleaning (slow cranking, over heat, light smoke).

Took it out and apart again. Looks like it overheats for some reason and burn the brushes. It's all black inside again.

Any ideas?
Thank you
 

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Chris1956

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The windings are usually coated with a varnish, to insulate them. Solvents and heat can destroy the varnish coating causing internal shorts. I expect that is what you are seeing. Time for a replacement.
 

AntonNZ

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Jul 13, 2019
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Yeah, probably...

I wonder what was the reason though. Don't want to install a new starter and have same problem again.
Can solenoid or bad battery or poor connection make the starter burnt? Or was it just me and previous owner who cranked it too long and overheated it multiple times?
 

Grub54891

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Jun 17, 2012
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5,908
Cranking to long can do it, also poor connections undersized wiring, or weak battery's can make them overheat. The starters WANT all the amps they can get, and rather quickly.
 

cptbill

Senior Chief Petty Officer
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Oct 6, 2012
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732
Don't forget to check the ground side of the main engine circuit
 

dingbat

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Nov 20, 2001
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15,417
Discolored areas on the armature is damaged/ burnt winding(s).

An under voltage condition (as voltage drops, amperage goes up) is the most likely culprit.

Excessive cranking
bad brush(es)
loose wire
old age, contamination and moisture. Breakdown of insulation properties of varnish.
 

AntonNZ

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Jul 13, 2019
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Took the starter motor to the starter repair service. They checked and said they weak springs caused poor brush connection. They made the brushes to fit, installed new springs. Works like a rocket now)))
PS: used the "Start ya bastard" spray for the cold start (spary inside the air intake) . Amazing stuff, engine starts in a second.
 

Silvertip

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Sep 22, 2003
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28,758
Keep using the starting fluid on a two stroke and your next post will be "why is my engine seized"?
 
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