MyChron 4 CHT Sensor Replacement

[Shane_B]

All- I had my MyChron 4 CHT Sensor break (ridgid lead off the plug ring broke) and tried an alternate cheaper solution instead of getting another $45 MyChron CHT and possibly breaking that too.

I found a CHT Thermocoupler sensor (14mm) with K-type plug on eBay for under $19 (to include shipping) - it has a braided stainless cable covering that is pliable vice ridgid like MyChron's (cable lead is 1 meter long). Initially it was giving false readings (-50 C) but found it was just that the leads were reversed... a jeweler's screwdriver and one minute later, CHT worked great.

The product is listed at: http://www.ebay.ca/itm/121081321413

Just wanted to put this out there for everyone as a cheaper CHT replacement option - I'm also going to contact the maker to see it the lead can be trimmed down from 1 meter without any calibration issues (don't see why not but will ask just the same).

[TAndersonV11]

You can trim any thermocouple sensor to any length you want. There is no calibration to be worried about. On K-type thermocouples, yellow wire is positive, red is negative.

Because an outboard engine turns, it is best to zip-tie the wire to the engine close to the spark plug.

[Shane_B]

My MyChron CHT probably broke because I did not zip tie it close to the plug - undoubtedly the lead was repeatedly hit by spray from my and other boats which also led to breaking of the MyChron's stiff lead (in addition to turning).

Thanks for the answer on trimming the sensor length!

UPDATE: Supplier responded re: lead length - as is as V11 states - no issue trimming lenth of lead as long as it is from the connector end... no calibration issues - those would only arise if you messed with the ring that goes under the sparkplug.

[Dave_E71]

I've bought from these folks. One warning though, I provided one of the EGT probes to Rossi to try and he said it failed almost immediately. Not sure how the under sparkplug thermocouples will last... They also sell the ends that plug into the Mychron harness

18mm http://www.ebay.com/itm/Thermocouple...item3aac5b1410

14mm http://www.ebay.com/itm/Thermocouple...item3aac4cdd47