I was researching the possibility of adding a water temperature gauge for my 1957 Johnson 30hp and 18hp. I saw a video where they screwed a sensor into the waterjacket housing of a Johnson outboard that apparently had a "blind" threaded hole with the correct size for a sensor, but that was for a newer motor. I can't find any information for installing this on older outboards. Is there a way to do it on these older motors? Thank you in advance.
I bought a Heat Chek (kit like pictured) off eBay. My 1957 EV Lark had one on it & I wanted a kit to see what it was about. You can look on MarineEngine.com in the J/E Accessories Parts book section. Starting in 1972 they had one kind of sensor (still available) & by 1976 had changed to the other style which is kinda universal. Has a bracket that mounts the sensor up against the head/block depending on application. The problem comes with the gauges. They are too slow to react to save your motor in most cases. That & unless you drive with one eye on them all the time you don't notice it climbing. An overheat is usually a quick thing & can be catastrophic! That is why later model engines have gone to horns & speed limiting systems to get the operators attention. JMHO
Guess I've always had a little different view on the modern-day overheat horn/limiting systems. By the time those go off, your motor is already in overheat mode. I've always relied on a gauge to help monitor engine temp and on the few occasions I've come close to an overheat condition I saw the gauge suddenly start to climb and got it shut down before the horn went off. I usually take a glance every few minutes at both the water pressure and temp gauges which are side-by-side on my console. I've found the modern BRP temp gauges and sending units to be pretty accurate by verifying engine temperature with an infrared temp gun.
Bob AOMCI Member
1954 Johnson CD-11 1958 Johnson QD-19 1972 Evinrude 25202