shop tach hookup89 70 johnson

[denny]

Just rebuilt my 89 johnson 70 model J70ILCEM<br />and want to know if I can use my handheld shop tach. It is 0-6000rpm hi-low and has two leads. One is supposed to hook to ground, the other to<br />the negative side of the coil. Also it it only has two settings 6 or 8 cyl. Since I only have three, was wondering if it could be used and where to hook up. The engine ran fine on inital start up on muffs but ready for fine tuning on the water. It did feel real warm at the thermostat but tattle tale water just warm.

 

[petryshyn]

Re: shop tach hookup89 70 johnson

sorry, can't use it. The tach will load down the primary voltage, possibly damaging pack, and the rpm will be out. In 6cyl. range, the tach counts 3 hits per revolution. In the 8cyl. position, the tach counts 4 hits per revolution. The outboard will have one hit per revolution.........