Fuel Bladder in carb

[caulkerguy]

I have a 1980 4.5 2 stroke Johnson outboard with a built in gas tank. I just rebuilt the carb and it has a fuel bladder...part 28 in attachment. Can anyone tell me the purpose of this part and how it works......Thanks, Mike

 

[racerone]

It is a simple " fuel pump " operated by crankcase positive and negative pressure pulses.

 

[caulkerguy]

Thanks...I sort of thought that's the way it worked with the vacuum line running to it from the crankcase . It was just for my knowledge ....didn't want to be just a parts changer. Thanks again, Mike

 

[racerone]

That very same little bladder was first seen in tecumseh engine outboards ( eska ),---Remember replacing one some 30 years ago.