Mercarb Power Jet Function?

[akbpilot]

Let me try this one more time, not sure where my first post went.

2000 Mercruiser 3.0L s/n OL650064. Am cleaning and re-building carb due to a fuel contamination problem. Does anyone know the function (how it works) of the power jet in the bottom of the bowl, and the associated plunger above it? Am cleaning and replacing all parts contained in repair kit, and can't quite figure out how the power jet works. It's not a big deal, but it bugs me when I can't figure out how something works. Thanks

 

[rodbolt]

Re: Mercarb Power Jet Function?

it works well.

 

[rodbolt]

Re: Mercarb Power Jet Function?

actually, the little needle valve looking thing the plunger from the airhorn sits on is the power valve.
while the engine is idling or operting at a low throttle angle opening intake vacum is high, the high vacum is ported to that airhorn plunger causing it to retract allowing the power valve needle to close forcing all the fuel to pass the main jets.
in the event of high angle opening or sudden opening ,intake vacum drops allowing the plunger to drop allowing a certain amount of fuel to bypass the main jets and enter the venturi cluster for additional power while allowing smaller main jetting for more efficient midrange and low speeds.
hope that helped a bit

 

[akbpilot]

Re: Mercarb Power Jet Function?

Thanks Rodbolt, sounds like I might have discovered the source of the problems I was having which led to my opening the carb in the first place.