15-09-2020, 10:23 AM
You could by a tacho for a diesel engine with a sensor they are available on Ebay for about 21 GBP inc the sensor here is a link to one
https://www.ebay.com.au/itm/85mm-Marine-...0009.m1982
https://www.ebay.com.au/itm/85mm-Marine-...0009.m1982
Cheers
Mark
Mark