Adding a Tach Gauge?

I see problems here. A charging indicator is likely to be more beneficial than a tach. The only way you will know it is not charging otherwise is when it fails to start. A tach might be nice as an addition, if there is an additional hole that is waiting to be filled. BUT, from what you typed, you don't need a tach to check it one time. There are even smartphone apps that are tachometers. They run off exhaust pulses. Also, have you done a cylinder balance test to see if both cylinders are firing equally? Felt the exhaust and cylinders to see if they are nearly the same temp? Checked compression on both cylinders? Adjusted the valves, replaced the plugs with known good ones directly from a known good supplier and not the online A store where there are a plethora of counterfeit plugs and substitutions in the fine print. You know the drill - photo is a sample of what you might get, brands subject to what you get... and then pray it isn't some unlabeled brand or Torch.
 
also - the tach you order has to be for the number of cylinders and the type of ignition system an engine has. The exception is one where a sensor is added to a flywheel or pulley and the tach reads off that. Some car tachs were even wired and calibrated to read off the alternator speed. Most 6o's and 70's tachs read the number of times the points opened and closed. Most of these engines do not have points. You will need a tach that reads plug wire pulses or a marker you attach to the flywheel or pulley. Never looked for one but that would be the way it would work unless you have an actual ignition module that can send a tach pulse, and it is unlikely you will find one on most of the engines in these motors. They work off one or two coils that rely on an airgap and a magnet that crosses the poles of the coil.
 
sgkent said:
I see problems here. A charging indicator is likely to be more beneficial than a tach. The only way you will know it is not charging otherwise is when it fails to start. A tach might be nice as an addition, if there is an additional hole that is waiting to be filled. BUT, from what you typed, you don't need a tach to check it one time. There are even smartphone apps that are tachometers. They run off exhaust pulses. Also, have you done a cylinder balance test to see if both cylinders are firing equally? Felt the exhaust and cylinders to see if they are nearly the same temp? Checked compression on both cylinders? Adjusted the valves, replaced the plugs with known good ones directly from a known good supplier and not the online A store where there are a plethora of counterfeit plugs and substitutions in the fine print. You know the drill - photo is a sample of what you might get, brands subject to what you get... and then pray it isn't some unlabeled brand or Torch.
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Yeah I'm not worried about taking it out because I have a separate battery indicator/charging plug that I installed in the dash. I will definitely be looking into the cylinder contribution more, but I did adjust the valves a few days ago and they were only very slightly out of spec.
 
sgkent said:
I see problems here. A charging indicator is likely to be more beneficial than a tach. The only way you will know it is not charging otherwise is when it fails to start. A tach might be nice as an addition, if there is an additional hole that is waiting to be filled. BUT, from what you typed, you don't need a tach to check it one time. There are even smartphone apps that are tachometers. They run off exhaust pulses. Also, have you done a cylinder balance test to see if both cylinders are firing equally? Felt the exhaust and cylinders to see if they are nearly the same temp? Checked compression on both cylinders? Adjusted the valves, replaced the plugs with known good ones directly from a known good supplier and not the online A store where there are a plethora of counterfeit plugs and substitutions in the fine print. You know the drill - photo is a sample of what you might get, brands subject to what you get... and then pray it isn't some unlabeled brand or Torch.
Click to expand...
well I just got around to checking some things out. I measured the exhaust temps and they stayed close to the same. Eventually found that a coil wasn't contributing at all, go try explain that 🤷‍♂️. I had one around that I pulled off a parts mower and it fired up and ran beautifully, like the other one. While I had the cover off, I did check the kill wire for any AC voltage and it was getting about 13vac. My multimeter is slow, so it didn't fluctuate much, but I'm thinking now that there's gotta be something a tach can use from that signal, right?
 
have to research it to see if someone has devised a tach or circuit. Seems like a lot of work with no gain. Not like a car where you are shifting gears at a set rpm. It may require a tach where you install some kind of sensor. You could look at the kill wire with an oscilloscope and see what kind of pulses you have there.
 
sgkent said:
have to research it to see if someone has devised a tach or circuit. Seems like a lot of work with no gain. Not like a car where you are shifting gears at a set rpm. It may require a tach where you install some kind of sensor. You could look at the kill wire with an oscilloscope and see what kind of pulses you have there.
Click to expand...
I found this related thread and it looks like the magnetos do generate some kind of pulse. I might just buy the tach and see if I can get it to do something.
 
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