Took boat/15 hp evenrude to lake for !st time since bringing it to NY for summer. Installed new water pump/impellar last fall and winterized it. Would not start at lake. New gas, bulb hard even used a little carb cleaner, got spark etc etc, finally gave up went home. Put things away and went to get tools, gave it one little pull and it fired right up. Put water in barrell and started it 4-5 times the rest of the day, one pull each time. What causes this? Sometimes I think it takes a little while for gas to get all the way thru the system, other times I think the fuel lines get kinked when I lift motor to trailer or back in water.