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56 Evinrude 30hp big twin single line conversion

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shelbygt

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Decided to start a new thread because other one I started is listed as carb question. Seems like most of the conversions talk about smaller motors and I want to make sure I get this right.

Is the existing pressure line coming out of the front (under/behind carb) pulsating, or is it only pressure? Has anyone here done this conversion with an old big twin?
 
It is a pulsating pressure, NOT an alternating pressure/vacuum. An alternating pressure/vacuum is what is required to operate a pump. If you want to go in there and modify it go ahead, but in my opinion it is kind of dumb---or at the least, a lot of un-necessary work. Simply tap a line into one of the bypass covers on the side of the cylinder.
 
You may find a bypass cover from other models will fit the 56 -30 HP and ready to mount the pump.----Look for the same part # of the cover gasket.---The pressure tanks are very well built and very reliable !
 
Well, pressure issue was stuck float not allowing needle to seat. Holding off on conversion for now, but will replace hoses and clamps. Thanks guys!

Worked on plenty of engines, just not boat engines. New territory.
 
All the lines seem to be sealed. Trouble was float rubbing against gasket and not allowing needle to seat so it couldn't build pressure. Crazy, huh?
 
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