starter motor

[alan54j]

My outboard wont start on its electric starter !
I managed to start it by jump start from my running car battery !
I replaced the old battery, starter solenoid and had the starter motor rebuilt. All cabling and earth points fully checked and..
same problem slow slow starter not enough to fire it up.
I assume there is a resistence somewhere. I bench tested the starter and it spun normally. Someone told me the coil in the starter could be faulty and would only show under load. Does anybody know if you can test the starter ciol with a normal multimeter ? or do I need a complete new starter.
regards alan

 

[Mal113]

Bench testing a starter without load tells you very little other than it spins. Take the starter back and have the company test it under load. Check the volt drop at the starter and note the volt while trying to start, then check the volt at the battery again while starting, they should be very nearly the same. If the battery voltage is high or does not drop much below the battery open circuit value then you have a high resistance between battery and starter.

 

[RONM]

Hi Alan,
You appear to have covered most of the bases, however in answer to your query, no you cannot test the field coils effectivly useing a multi meter. Does your starter have field coils? most modern starters have permanent magnet fields nowardays.
You need to establish is your starter drawing too much or too little current. Assuming your battery is fully charged, connect a voltmeter across the battery and crank the engine. voltage dropping below 9v with sluggish cranking would indicate high current, suspect short circuit armature, field coils(if Fitted) or worn armature end bush. Conversly if the voltage remains high then current is low, suspect high resistance wiring, solenoid contacts or poor commutation i.e. brushes.
Very basic but effective test, hope it helps.

Regards Ron

 

[pampas]

Engine tight to turn by hand? Squirt some engine oil down Plug hole then turn over a couple of strokes,put plug back and wait for 1/2hr then try starting again and see if its made any difference.

 

[William_H]

One mode of failure for an armature is shorted turns of the coils. This results in high current drain and very little torque. It is tested by a competent shop using a growler. Here an 50 hertz AC field comes out to pole pieces about 30cms apart. The armature is rotated in this field so that the various coils can be excited by the AC field.

A coil with shorted turns growls, vibrates and generally carries on as the field is subject to a load. You might have 4 to 8 individual coils each connected to a pair of brush segments.
A top of the range multimeter might have an inductance readout which will also show bad coils by checking from the comutator segments opposite one another.

Simplest perhaps to get a competent shop to test it under load. Assuming all the above tests ie voltage to the starter and engine friction are OK. good luck olewill