I hate to ask this and I know it sound stupid, but I'm pretty newat this boat stuff, what is the difference between a four stroke and a two stroke motor, be gentle with me.

simplest explination,
2 stroke you have to mix the gas and oil
4 stroke no mixing

EX:
Weedeater -2 stoke
riding lawnmower - 4 stroke

also i have heard the 4 stroke are better on gas. and are quieter.

AND.........4 strokes cost a little bit more...weigh a little bit more.......and have less low end "jump out of the water" power than 2 cycles. (a prop change can correct some of the low end power loss).

four phases of internal combustion in a piston engine: intake, compression, ignition, exhaust - a 4-stroke takes four strokes of the piston to accomplish each cycle (out, in, out, in), each spark plug firing on every other rotation of the crankshaft. A 2-stroke takes two strokes to accomplish the same: intake underneath the piston during the compression stroke, and exhaust on the back half of the power stroke - each spark plug fires on every rotation of the crankshaft. Four-stroke has a valve train (intake and exhaust valves, cam, push-rods in some engines, timing belt or chain) lubricated by an oil pump. Two-stroke accomplishes intake and exhaust via ports in the cylinder walls eliminating the need for the valve train. Result is a significantly better power-to-weight ratio but generally a less efficient fuel burn.

SOME 4 strokes get better gas mileage in some applications but the 2 stroke is as good in bass boat applications from the reviews I have read.

Most of the new 4 strokes have superior emissions to most of the current 2 stroke motors.

The 4 strokes can save in other ways such as much less oil usage. You change the motor oil I think at something like 10 hours and then not again till 100 hours. In a 2 stroke you will burn at least 5 times the oil in that time period.

As far as reliability, its not yet clear but the 4 strokes may turn out to be more reliable than a 2 stroke. They haven't been out too long.

On the cost thingy, it really pays to shop around.
I now have 110 hours on my 150 Yamaha, I have spent a total of $60 for oil and filters.
The hole shot is not close to a 2 stroke, the top end is lower, the "cruise" economy is better in my opinion.


George