Coil OHM Reading Help

[johninmo]

I have a 99 V MAX 150 and I am having problems with my boat getting on plane as I have explained in a previous post. I tested the coils by using my multimeter and putting the red lead in the end of the plug wire and the black lead on the black wire that has the bullet connecter. My readings was 9.3, 9.6, 9.8, 10.1, 10.1 and 65.5 when I finally got it to kinda stabilize. They all have fire when I stick a screwdriver in the end and arch it to the block while cranking even the one that reads 65.5. So could the one that reads high be messing up once I put it under load and accelerate? Why is the reading so out of line with all the other ones? And is this coil OK?

Thanks

 

[JoLin]

I'm not sure about the right answer, but I don't think you've completely tracd the high ohms problem. If I read you right, your test is reading both the coil and spark plug cable at the same time. I had a high ohms reading on one coil/cable (14 ohms vs 5 in the spec) on my 85 hp Yamaha, and traced it to the plug cable. I don't have the manual in front of me and don't recall exactly how I did that.

Not wanting to buy a complete coil and cable assembly ($90.), I cut the cable back 1/2 inch, installed a new connector and boot ($6.00 from Yamaha), and the reading fell into line with the factory spec and the other 2 coils/cables.

My .02