Re: tachometer (accessory) question

[David Stanton]

There are a lot of differences in tachometers. OMC used Airguide tachometers for many years. Here’s a link to airguide marine tach models and what they fit. Note the model 653 is shown for private label OMC tachs with magnetos, model 654 is not:
Dave

http://www.classicboatwork.com/classicp … 0Guide.pdf