Re: 63 Evinrude Starflight 75 HP putting out alot of exuast
If this motor is new to you, and you are not used to the amount of smoke it puts out normally, there may not be anything wrong with it at all. The early 60s OMC do smoke quite a bit, especially if they are run at a 24:1 fuel/oil mix.
The difference in smoke that you are seeing on the water hose v. in the water, probably has to do with the back pressure that is created when the motor is at idle, and is in the water. I don't think there is really any more smoke, but when it is mostly forced out via the midsection exhaust relief outlet, it appears that there is. When on the hose, you are going to get exhaust exiting via the lower outlet for the most part, with some out of the midsection outlet. The warm exhaust will then mix with relatively warm air, and dissapate pretty effectively. When it is mostly coming out of the midpoint, with relatively cool water underneath, the warm exhaust and smoke is going to rise right into your face, if you are looking over the transom. You'll also get some warm exhaust bubbling straight up out of the water.
Be aware, also, that these motors waste a lot of fuel by dumping it overboard. That's why they are so terrible in terms of fuel consumption.
If you still think your motor is smoking excessively, I would make sure that the mixtures are adjusted properly, and that the carbs are synced with the spark advance. I think that the guys here that know the old V4s will tell you that either issue can cause excessive fuel use, which will result a rich, smokey mixture.
On the rebuild issue, check the compression values, if they are good, your engine is probably fine. Also keep in mind that smokey exhaust v. piston/ring condition is more of a 4-stoke engine issue. In those motors, when rings and/or valves are worn/burnt, crankcase oil is burned, causing a smokey exhaust. In a 2-stroke motor, there is no oil in a crankcase, and three are no valves. The lubricating oil is mixed in the fuel or injected, so the oil is burned by default. This is where the 24:1 mix v. the 50:1 mix in the older motors (non-injected) comes into play - the more oil in the mix, the smokier the exhaust is going to be.
