Testing a Mychron 4

Buying used Mychron 4 2t tomorrow. Is there a way to test the unit for rpm without an engine being hooked up to it?

Nothing comes to mind. If you’re purchasing the gauge in person, a lawn mower, snow blower or weed wacker might work. I’d be more concerned that the display was in good condition and didn’t have any burnt out areas. Another concern would be that it would communicate with a DataKey. If the seller agrees, use PayPal so you will have some recourse if the gauge has a problem.

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I’ve tested them with a lawn mower for the spark, and then running a fridge magnet under the mag pick up randomly to see if that works. You could put the unit near the plug lead on any running engine really.

However, I’ve been through quite a few Mychron 4 units, the rpm never failed on me once.

What does fail:

  1. Micro switches for the buttons
  2. Water seals fail and cause mayhem inside
  3. All the sockets can fail at the joins, can be very difficult to repair with solder
  4. Screens give up occasionally

No problems so far with the Mychron 5 though.

Thank you gentlemen, I’ve never had one fail BUT you never know and neither of us (buyer or seller) will have a kart there.
The price is right and he is a Karter getting out (that’s just crazy) of racing.

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Talk him back into karting after you get the mychron :smiley:

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On anything electronic check the battery compartment to see is it if had batteries leak in the past. If it is corroded I’d pass on it.

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Guys I got the Mychron 4 2t I asked about yesterday, everything works great. Something someone said caught my eye about the unit not being water proof.
Being the master techs we are…has anyone tried using dielectric grease on the buttons, sockets on the back and even around the edge of the screen? ???

they make simple over-covers which makes them pretty rain resistant. I’ve even seen ziploc bags used with decent success.

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Some of them are water-proof, just the few I had weren’t :smiley:

I suspect if yours is trouble free it is one of the good ones

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I hope so, here in Florida we run in the rain a lot and you need to be ready.
I ran the unit on the kart last night and it’s working great.

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