Re: 3hp Johnson/Evinrude '60's twins.
On the '62, start by makeing sure you have adequate flow from the fuel tank to the carb. There is originally a fuel filter up inside the tank which will clog on you. Remove the large brass nut just above the fuel petcock to reveal it.<br />To test for overheating, put a drop of water on the cylinder head. If it sizzles you have an overheat problem. We can diagnose from there.<br /><br />Ignition coils are a common source of problems on these engines as the original ones' insulation would crack. That would cause the ignition to fail either by arcing over as the RPMS picked up or by getting water into them, which would kill spark altogether. You can buff out the points yourself and save the cost of them. Condensors from this period only rarely had problems so you can pretty well assume they're all right. New spark plug wires might be a good idea if your old ones are cracked. Use metal core plug wire only!<br /><br />Since the ignition coils were so frequently a problem, new ones are easily and cheaply available. The factory one sells here for about $25 CAD each, while the aftermarket (Sierra 18-5181) sells for about ~$20 each. I personally think the aftermarket one is superior to the factory coil, but both are much better than the originals. Lark2004 may know where to find these parts local to you.<br /><br />The initial setting for the carbs is, take the knobs off and screw both controls all the way in until they seat (gently!). Then unscrew the low speed ones 1 and 1/2 turns, and the high speed 3/4 turn. This will be rich, so you'll have to turn them in.<br /><br />The 3hp engines are really great running engines. There's tonnes of good information on them over at Tom Travis' site, including a '52 3hp owners manual:
http://www.outboard-boat-motor-repair.com/ <br /><br />Oh, and last, there is no tell-tale on these engines. Just feel for a mist coming from the holes on the midsection where the idle exhaust comes out. If your hand doesn't get wet, shut it down. If the water pump impeller hasn't been changed in a few years, it's due. Especially if they're used in salt water because the bolts will seize. Fortunately, changing them on that engine is dead easy, so long as you do not pull up on the driveshaft when the water pump housing is off.