A few weeks ago, as I was accelerating through a holeshot, I felt something give in the big motor. There was a loud, clanking sound and then it shut down. I knew what it was right away. While the motor was being repaired, I did a little homework on causes and trends with hopes of finding something, anything, I could use as preventive measures. I learned a few things to add to my outboard awareness.
Outboard Awareness – Temperature Surge
We all know the effects of temperature on outboard motors. We all know the scenario: a tournament angler blasts off and runs wide-open-throttle (WOT) to his special spot, then powers down a couple cast lengths away. The big motor goes from WOT to zero RPMs in a matter of seconds. What I didn’t know until I my research; the temperature of the motor continues to climb several minutes after shutting down. This rise in temperature happens at the same time water is draining from the cooling ports. Fast-rising temperatures + absence of coolant = a formula for disaster.
Outboard Awareness – The Experiment
As I was going through the break-in process, I made it a point to monitor motor temperature after I came off plane. Sure enough, within about 30 seconds the temperature would rise by as much as 16 degrees. This occurred while coolant was still being pumped throughout the motor. Now, think about this occurring after shutting down at the end of a 20-mile run at WOT. The motor temp could rise by more than 100 degrees in less than a minute and there’s no coolant circulating. From what I’ve gathered, there’s nothing firm in scientific or engineering terms, but the anecdotal evidence strongly suggests a correlation between repeated rapid temperature surges, absence of coolant, and mechanical failure.
Outboard Awareness – The Fix
Boaters can easily mitigate the effects of temperature surge – let the motor stabilize. During my little experiment, I learned the temperature on my outboard would begin surging about 15 seconds after coming off plane. The temperature peaks at about 30-40 seconds and holds steady for about another 10 seconds. Then it starts falling. The entire process takes about a minute. Once I saw the temp start to fall, I shut down. Taking a minute to idle could be a major contributor to outboard motor longevity and performance.
Outboard Awareness – The Kit
In retrospect, the smartest add-on I put on my boat was the SmartCraft digital gauge. Among other things, it gives me real time temperature readings. I have it placed close to my water pressure gauge and voltage indicator. Together these tools give me a snapshot of my outboard’s health at any given time. I know the normal idle temperature (114-118 degrees F), normal running temperature (123-125 degrees F), and surge temperature (134-140 degrees F). I had no idea how valuable this little gizmo was until I learned about temperature surge. Turns out to be the smartest $145 I’ve ever spent.
Putting it into practice – I’m just as eager to get to my favorite spot as any angler, but I won’t do so at the potential expense of my outboard. By taking a minute to allow the big motor to stabilize, I may be eliminating a major contributor to component failure. Again, the evidence is anecdotal, but it’s only a minute. For me, it’s worth the wait to make the first cast.
B. Lindamood
