Mercruiser 454 Mag Carb Rebuild: DIY

OffshoreDrilling

This is my safe space
TCG Sponsor
TCG Premium
HVAC Guy
Aug 28, 2007
39,147
50,295
Homer Glen
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.
iOhP6j4.jpg


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.
H1yHKLA.jpg

gJak7KQ.jpg


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
UsvE7sl.jpg


Disassembled the rest of the carb and kitted it into plastic bins for organization
4HjH8bg.jpg


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.

JcPFeOB.jpg


New parts kit

zSqgNvj.jpg


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:
esyAPwM.jpg


All better.
IpOBFcM.jpg


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

CbYUK9Y.jpg


Adjusted.

24giR8i.jpg


All back together!
zJr9Wuo.jpg


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.
 
Old Thread: Hello . There have been no replies in this thread for 90 days.
Content in this thread may no longer be relevant. Consider starting a new thread to get fresh replies.

Thread Info