Yamaha C115 Ignition coil resistance

[Thbnf376]

I have a used 4-cyl 2-stroke C115TLRX outboard 1999. The ignition coil resistance, plug wire to ground, is about 9100 ohms on two ignition coils and 4400 ohms on the other two.

The suggested replacement coil for this engine is 6R3-85570-01-00. Can anyone tell me what the resistance should be?

[madharchod]

the resistance should be the same for all the coils ie 9100ohms

[rodbolt17]

what is the year model and does it have resistor type plug caps?

[Thbnf376]

Model year is 1999. The installed plugs are NGK BR8HS. They measure 5100 ohms on my meter.

[Thbnf376]

I know they should be the same, but should they be 9000 or 4000 ohms? I have a chance to select different coils from the rebuilder and want to know which ones to use.

[99yam40]

according to this CDI Electronics Practical Outboard Ignition Troubleshooting

1995 - 2000 115 2 stroke
coil primary .5 ohms
coil secondary 2.5K ohms
Plug cap 4-5 K

[rodbolt17]

and thats why we asked if you have resistor caps or not.
if so unscrew them and test them seperatly.
not all V4 motors used resistor caps.

[Thbnf376]

There are no removable resistor caps on the ignition leads. The coil, lead, and spark plug cap are one assembly.

[rodbolt17]

either way, the plug caps can be removed.
on the non resistor type cap you will typically destroy the cap spring.
however new coils dont come with the boot and spring.
secondary resistance should be 2.5K on the C115 from 84-2000.

[Thbnf376]

Thanks, I didn't know that the plug cap had its own resistor.

One more question. If the cap has a resistor, should I be using resistor-type spark plugs (BR8HS) or the non-resistor type (B8HS)?

[rodbolt17]

the BR is an acceptable subsitute for any engine calling for a B.
the B is NOT an acceptable substitute for a motor calling for a BR.