I have a 1993 Johnson 40hp. The tach was disconnected when I bought the boat. I hard wired the tach plug and ran it to the tach. It ran backwards for some reason. I got my multi meter and checked the wires. Purple is 12v. Ground is good. Grey is 11ish v when running. I thought the tach may be bad. I just installed a new tach with pointer on 6p and I have the same symptoms. I have driven the boat for hours since the purchase and the charging system seems to be functioning. I've always had I/O and inboards so please pardon my ignorance.
Here's a video of the tach.
Tachometer running backwards. 1993 Johnson 40hp - YouTube
Thanks in advance!
Here's a video of the tach.
Tachometer running backwards. 1993 Johnson 40hp - YouTube
Thanks in advance!