40hp johnson no tach

[fred b.]

Hey guys I bought this boat a few months go. had some issues with motor so eliminated the VRO as part of the diagnostic of possible issues. Tach was not working right before this but new tach won't work at all. Did eliminating the Vro also take out the tach. Wire colors are same on the connector I unplugged from VRO. Is there a way to rewire. The female end of connection is still there. Motor is 1996 Johnson 40hp. Any help greatly appreciated.

 

[VicS]

Check that the tach has power ( check the ground too)
I believe on this engine the tach takes its signal from one of the stator AC outputs to the rectifier. Check that out.

Confirm that the engine is charging the battery

I suggest you post your question on the Johnson / Evinrude board of either the iBoats forms and/or the Marine Engine forums

Johnson & Evinrude Outboards
Johnson Evinrude Outboard Forum

If you go to either of these quote the full engine details including the model number

There is a small section on testing tachometers in the CDI Electronics Troubleshooting Guide ( page 8) but you will need a meter with a DVA adapter ( also explained in the CDI guide)
https://www.cdielectronics.com/wp-content/uploads/2013/02/CDI Troubleshooting Guide - 2012.pdf

 

[Stemar]

If you can't get it working, a useful "cheat" might be a Tiny Tach that picks up pulses from a plug wire

 

[fred b.]

Check that the tach has power ( check the ground too)
I believe on this engine the tach takes its signal from one of the stator AC outputs to the rectifier. Check that out.

Confirm that the engine is charging the battery

I suggest you post your question on the Johnson / Evinrude board of either the iBoats forms and/or the Marine Engine forums

Johnson & Evinrude Outboards
Johnson Evinrude Outboard Forum

If you go to either of these quote the full engine details including the model number

There is a small section on testing tachometers in the CDI Electronics Troubleshooting Guide ( page 8) but you will need a meter with a DVA adapter ( also explained in the CDI guide)
https://www.cdielectronics.com/wp-content/uploads/2013/02/CDI Troubleshooting Guide - 2012.pdf

Check that the tach has power ( check the ground too)
I believe on this engine the tach takes its signal from one of the stator AC outputs to the rectifier. Check that out.

Confirm that the engine is charging the battery

I suggest you post your question on the Johnson / Evinrude board of either the iBoats forms and/or the Marine Engine forums

Johnson & Evinrude Outboards
Johnson Evinrude Outboard Forum

If you go to either of these quote the full engine details including the model number

There is a small section on testing tachometers in the CDI Electronics Troubleshooting Guide ( page 8) but you will need a meter with a DVA adapter ( also explained in the CDI guide)
https://www.cdielectronics.com/wp-content/uploads/2013/02/CDI Troubleshooting Guide - 2012.pdf

Thanks for all the great info. I never checked if battery is getting a charge. That would tell me a lot. Tack has power. Lights up and ratio settings come up and are changeable so I think I'm not getting pulse from engine. The boat is new to me and I have never had a boat this big or a tach, or VRO etc. so this has been challenging figuring these things out. Boat came with 2 repair manuals, and a few spare parts. I had also done a lot of work on an old 1979 35 hp I found laying in a guys back yard, and bought. It's always amazing to me how well you can get old gas engines to run most of the time. Problems usually fuel or spark, but owners gave up on them. Then the years go by and they never run again. Or someone finds them and brings them back to life. I'll take a look at sites you mentioned. Thanks for the input.