Mercury 6hp 4 Stroke Fuel Flow Problem

[southplank]

I have a Mercury 6hp, 4 stroke. Fairly new, it is my second season. I'm having a problem that I have seen only twice. If it dries out of gas, it is hard to start. By 'dry out', I mean the carb is dry, fuel filter empty, and the fuel pump is likely dry also. It seems it takes way too many pulls (20?) to get gas moving again and visible in the fuel filter. This occurred once right after winter storage and again today after it sat for a over a week unused outdoors in hot weather. Today, it seemed like it would never pump gas. I finally opened the fuel line at the filter and squirted some gas toward the fuel pump and with one more pull, the gas began to flow. I suspect if I had an external fuel tank with squeeze ball, this would not be an issue. I only use the internal tank and it acts like the fuel pump is air locked or just somehow stuck. Tank is nearly full and vent was open. Any suggestions? I am considering not running it dry after use and leaving the fuel valve open even if I won't be using it for a few days just to keep the pump wet.

 

[southplank]

Just a follow up post is case somebody else has this issue...

After talking to old timers, doing some deeper googling and staring at my motor for awhile, I have to conclude this is normal behavior for a small, dry/un-primed diaphragm fuel pump and no external fuel tank on this motor. I found some others with the same issue. Looking at the motor, there is about 3 feet of fuel line tucked in this little motor between the tank and the fuel pump. Not much gravity flow with the small capacity tank and the fuel line looped back and forth to the shutoff valve. Its only a tiny diaphragm pump, I can't expect it to quickly and easily suck gas through 3 feet of line without some help to get it wet. That's why we have primer bulbs on external tanks. Next spring, I'll just open the line leading to the fuel pump to get the gas flowing and save myself some pulling. I won't let the motor sit for 2 weeks again without running during the season.