Check/Fix/Replace Starter Motor 1996 50hp

[Mc Tool]

Thanks everybody. I arrived back from holiday, went to the boat with a better understanding of voltage drop testing. I have found a voltage drop of 1.5 V from the engine's ground back to the -ve battery post. My first job is to sort this out with new cable and connectors. More testing to follow.

Yep , you may find few more like that too and whilst 1.5v seems small (its not ) they add up .
while doing the test the meter is telling you the difference in potential between the two probes, ideally there would be none .

 

[Crosbyman]

check the video ... you could even loose that voltage between a nut and post .. make certain you scratch the b- post clean and shiny..also make certain you see 0.00 V when probes are shorted together. Meters can be iffy sometimes.

Personnal I love my old telco analog Ks 14150 meter with a " x1" scale I can 0 out with probes shorted when measuring resistances

the 3 Volts scale is great to.

 

[saltchuckmatt]

check the video ... you could even loose that voltage between a nut and post .. make certain you scratch the b- post clean and shiny..also make certain you see 0.00 V when probes are shorted together. Meters can be iffy sometimes.

Personnal I love my old telco analog Ks 14150 meter with a " x1" scale I can 0 out with probes shorted when measuring resistances

the 3 Volts scale is great to.
View attachment 415040

Yes, and rumer has it 3 nine volt battery's in series makes it work!

 

[janul15]

Hello again. Been back top do some things advised in your replies. Flywheel off, checked for Woodruff key, it's in place and looks good. The ring magnet showed surface rust, so I lightly sanded it, a bit cleaner. Tested the ignition timing. It is well advanced. But, here's the odd thing; adjusting the spark control rod doesn't appear to change anything. I extended the rod all the way, and the timing is still well advanced. What could be wrong?

 

[janul15]

Success! Read on this forum about lapping the crankshaft and flywheel. So I removed the flywheel, cleaned the surface of the ring magnet, took out the key, lapped the flywheel/crankshaft, replaced the key, then replaced the flywheel. This now sits about 2mm lower on the crankshaft. Result; starter now spins the flywheel without previous issues, and timing is now near to perfect.