Mercruiser 454 Mag Carb Rebuild: DIY

OffshoreDrilling

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Cleaning and rebuilding the carb from my boat has been on the short list of projects to get done this pre-season. After all the misc. mechanical issues I had last year and going over all the other basic maintenance items on the boat, this was the last thing to knock out.

I have almost zero knowledge about carbs other than a very basic understanding of how they work and being able to point my finger at a couple of the components and name them. This is my first time working on an automotive carb.

The process:

Pre tear down. I snapped pictures of all sides of the carb so I could put it back together with linkages and such in the same locations without fiddling around.


Screws removed from the bowl cover and the top half pulled off. Initial impression wasn't terrible, just a bit of schmoo in the bottom of one bowl.



I took off the floats and yanked out the needle and seat assemblies. One of the screens was jammed up with a good amount of junk


Disassembled the rest of the carb and kitted it into plastic bins for organization


Washed everything in an ultrasonic bath of hot water and simple green. These are an amazing tool, they get absolutely everything off of internal passages with zero scrubbing. Gave all the parts a hose down of carb cleaner to remove any residue left from the bath or oils.



New parts kit



Re assembled the same way it came apart and started making adjustments to what was necessary. Free hanging float to bowl cover spec 15/16", actual 2" + :bowrofl:


All better.


The other float setting needed to be made is float position with the needles seated. Spec is 5/16"....



Adjusted.



All back together!


All in all it wasn't terribly dirty or trashed but I should definitely see some improvements. Not a very difficult project per se. I learned a lot about how the carb works which is always a plus. This is why I like to do things myself even if I have no experience. So many of the things I've become an knowledgeable on have been from jumping into it and learning as I go. Watching a video or reading a piece of text only goes so far.
 

OffshoreDrilling

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Trash find at work too :bowrofl:


Tried to get them to buy me a big one I could put some decent size parts in
 

bikrboy128

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nice work! :fy:
you have an ultrasonic cleaner at your disposal? my magna carbs are in need of a good deep cleaning.
 

RICH17

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Fuck you and these trash finds....
 

bikrboy128

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Lemme know, I'll give them a dunk
:fy: i'll hit you up if i ever feel motivated enough to take apart 4 carbs (again) :rofl:

that harbor freight cleaner is enticing though. do you use a detergent? im sure i could find a million uses for one of these.
 

OffshoreDrilling

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:fy: i'll hit you up if i ever feel motivated enough to take apart 4 carbs (again) :rofl:

that harbor freight cleaner is enticing though. do you use a detergent? im sure i could find a million uses for one of these.
I just use some simple green
 

OffshoreDrilling

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I had the parts in there less than 5min. The heavier the deposits the longer you need to let it sit
 

Chester Copperpot

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I've got an ultrasonic cleaner for my brass for reloading. The thing is awesome.

Maybe I should use it for small shit like that, I didn't even think about that.
 

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