I think your question is a super good one! One that I wish I coudl have had answered many years ago. I think the best thing for you would be a simple explanation of how an "old" 2 stroke carbureted engine works and I'll attempt to explain it so you can crank it if it gets "finicky".
Here goes:
A 2 stroke outboard gets fuel into the cylinders by sucking it around the side of the crankcase. To get to the side of the crankcase, the fuel has to pass through a tiny hole in the carburetor. By passing through the tiny hole the fuel/oil becomes an aerosol (tiny droplets) just like spray paint does in a spray can. Old two strokes use a choke ( a plate that cuts off air from the carb throat into the crankcase) to force the motor to suck harder on the carb's tiny hole that the fuel comes out of because it can't get air from the carb throat anymore since it's "choked" off. This causes more fuel than normal to pass out of the carb and into the crankcase, richening the mixture with more fuel for it to get started off of the first time. Once the engine gets started you can usually let off the choke, however, the engine may like to have a little choke for a few seconds while it's still warming up. If it gets too much choke it will suck in too much fuel and load the cylinders up and kill the spark by getting the plugs wet with fuel. Fuel/oil is nonconductive and acts as an insulator, keeping the spark from jumping and therefore stalling the motor. So, if it dies while your choking it, then STOP choking it and turn the motor over OFF choke so the compression of the pistons coming up to the top of the cylinder will produce enough pressure to blow out the fuel from the cylinder and hopefully dry out the spark plugs a little.
One more thing-- the carb float bowl needs to be full of fuel, so pump the primer bulb on the hose to fill the float bowl. If the carb float and needle valve are working properly, you should feel the primer bulb get firm and STOP priming it. If you keep priming, you could overcome the float and put too much fuel in the carb, flooding the engine. Just be gentle.
SOme 2-stroke carbed motors have a primer on the carb which squirts fuel into the crankcase to richen the fuel/air mixture with fuel for intitial cold starts, rather than have a choke.
If you prime the engine after it's warmed up, it will flood the cylinders with too much fuel and kill it, just like overchoking an engine that has a choke.
So, for my OMC motors, I pump the primer bulb on the hose and choke the engine before initially turning it over with the starter. Once it cranks, I let off the choke and it should smooth out and run perfectly. If it falters, I rechoke and try again, listening/feeling to tell if it wants more choke, judging so by how smooth it's running. Once it's running smoothly I let off the choke. If it dies you need more choke. If you keep the choke on too long and it dies, turn the choke OFF to clear the cylinders of excess fuel and turn the starter on with the fast idle lever in the up position until it cranks up.
If you post what engine you're talking about, we could be a lot more specific as to the start-up procedure.
BTW, this is just my feeble understanding of the motor (I'm not a mechanic) so hopefully some of the real experts will fix any of my current misconceptions, fixing me at the same time as you.:redface:
Hope this helps,
JBJ
