Re: Installing tell-tales really necessary?
I don't think I would bother with an old, pin drive motor. Those engnes have "mid-leg" exhaust and you can see whether you are pumping water upon startup. Further, the small ones that tend to be tiller steered lend themselves to frequent checking, just because you can look back to the exhaust point easily.
I installed a telltale in my '72 Johnson 65hp and don't regret it. I look back at my motor frequently and don't feel like doing so is all that big a deal. On one occassion that I can think of, I noticed the water "sputtering" and, sure enough, I had some duckweed around the upper/mid part of the gearcase.
Another thing that I use mine for, is to check water circulation while backing away from the bank of a bayou. I shoot a lot of photographs out of my boat and that means nosing ino a bank or drifting just off of one quite a bit. Our bayous get very shallow along the banks, with a soft mud bottom in most places. Sometimes the skeg and a bit of the prop will dig in and when its time to move, I don't like to power out in forward. What I do, instead, is to move away in reverse and use throttle to get the motor to "kick up" (I don't have T&T) out of the mud. I can control the angle of the motor with throttle and the tell tale lets me know that I am still deep enough for good water flow, because I can see it coming out of the engine.
Whether or not to install a telltale is a personal choice and certainly doesn't hurt, if you do it properly. I agree with those here who have said to mount it high in your cooling system. I did that and every time I start it up, it blows air out of the upper water passages.
All of this said, I also agree with those that suggest that a telltale is not the only thing that you should rely on. Others have mentioned some of the choices and I would add that simply listening to your motor can tell you quite a bit. Get used to what your motor sounds like under various conditions and more importantly, listen for changes in sound at times that you haven't done anything to cause that. If you do hear such a change, its time to start finding out why, and weeds around the gearcase is often the culprit.
Another sound/sight issue relates to water depth. One thing that I have found by having to deal so much with shallow bayous, is that a planing hull will squeeze water as it moves through a shallow area. This is kind of hard to explain, but it has to do with the fact, that as the bottom rises and the distance between it and the bottom of the boat becomes very small, the water will compress and come off of the transom differently. There is a resulting difference in the sound of the boat moving through the water and if you happen to look back, the boat will appear to be riding higher in the water. I think this phenominon is less noticeable at higher speeds, but I don't tend to run very fast and have been able to predict when I might bottom out before I actually do, by paying attention to this.
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