2002 f115 not charging

malibuguy

Cadet
Joined
Feb 25, 2002
Messages
16
I need a little direction here. Today after running about 1/2 hour, I stopped and shut off the engine and it wouldn.t restart. Pull off the cover and the flywheel nut had come off and the flywheel was loose. Limped into a marina on my kicker and a marine tech fixed it up-new flywheel key, reassembled and we were on our way. Noticed the voltage was low so we blasted home. Got back to the dock and after lifting the motor the battery was dead. came home and checked and there is no charging. Went through the diag in the clymer manual.There is power and ground at the red and black wires at the rectifier. They call for a harness to check the rectifier which i don't have. I assume the rectifier is a group of diodes to change AC output to DC to charge the battery. Pulled off the rectifier and checked it with an ohmeter. From the terminal that the red wire plugs into on the rectifier there is 305 Ohms on the to all three terminals on the rectifier that lead to the coil and when you switch the leads there is 285 Ohms from red terminal to all 3 terminals to the coil. According to the manual there should be 100-300 Ohms 1 direction and No Continuety the other direction. The results are similar when you test from the neg (black) to the 3 wires that lead to the coil. This would indicate to me that the diodes are shorted. Can anyone point me in the right direction here? By the way, The 3 wires through the coil all have 5 Ohms resistence through each other. This would be the same in a car alternator so I believe the stator coil is ok
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: 2002 f115 not charging

yes I do.
however your going about it wrong.
best way is stator volts into the regulator and DC volts out.
at 1500 RPM you should have about 37V unloaded and the regulator output should be about 13.5Vdc loaded. if the input is there and the output is battery voltage the only thing it can be is a bad regulator assy.
your test description is nasty as you dont test the stator coils with a diade check. no diodes in the stator assy.
did you test all stator leads for shorts to ground?
its a simple system,ac voltage into the regulator\rectifier and DC volts out.
but I am not there to test it and best you can do is buy the real service manual and leave the clymer in the outhouse for guest use.
 

malibuguy

Cadet
Joined
Feb 25, 2002
Messages
16
Re: 2002 f115 not charging

Thanks for your reply Rodbolt. I am away for a couple of days and then I will do the tests. I will let you know......
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: 2002 f115 not charging

the above linked test may or may not work with the F115 regulator\rectifier assy. Yamaha reccomends a similar test but using a meter with a diode test function that can fwd bias a diode and actually test it. not all meters supply enough voltage through the meter leads to fwd or reverse bias the diodes and can lead to inaccurate readings.
but voltage inputs and outputs with circuits loaded and unloaded as per the manual simply dont lie.
regulated systems simply have more internal circuitry and can lead to more confusion than the old simple 3 and 4 wire rectified unregulated charging systems.
 

malibuguy

Cadet
Joined
Feb 25, 2002
Messages
16
Re: 2002 f115 not charging

Rodbolt,
I tested the stator leads to ground and all three have less than 1 ohm to ground. I guess when the flywheel came loose, the stator was rubbed and shorted to ground. You can see that the flywheel had rubbed on the outer surface of the stator. The inside of the flywheel looks ok. Can you get the charge coil separate from the base? The manual shows it as a separate part.
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: 2002 f115 not charging

ill look.
what your looking for is the lighting coil.
the other two are pulser coils.
shorts to ground suck.
and it is possible to see correct resistance between the leads and still have one shorted to ground on a two or three wire coil.
its why BOTH tests are nessasary when testing a multiple wire coil.
 

malibuguy

Cadet
Joined
Feb 25, 2002
Messages
16
Re: 2002 f115 not charging

Thanks for your help guys. I replaced the stator and it is charging fine now. I guess when the flywheel came loose it rubbed the stator and shorted it out. I suspect the flywheel nut wasn't properly torqued so that was probably the cause. I have not had the flywheel off prior to this but this motor is new to me. It is now torqued to 140 ft/lbs. Thanks again for your help
 
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