1974 Mercruiser Manifold & elbow

[ibboater]

I have traced my overheating problem to plugged up manifold and elbow with rust and deposits,I have soaked both in muratic acid and the maintance book says to rod out the manifold, but dosen't tell how to do it. Can anyone tell me how this is done and is this the best way to clean them out to insure max.water flow?
Also, instead of using the stern drive water pump, could I use a water pump like a bait pump and run a hose to the intake side of the engine water pump??

 

[ziggy]

Re: 1974 Mercruiser Manifold & elbow

the way i understand it. once a manifold and riser are done, there done and ya need a new set.
as for the seawater pump. i can't imagine a baitwell pump having enough gumption to cool your engine. why do you want to do that?
might be nice to know what your working on too. engine and drive wise...

 

[Surfdancer]

Re: 1974 Mercruiser Manifold & elbow

I've rodded out manifolds before by poking out the loose crud with a coat hanger (heavy steel wire), then looping up a coat hanger and chucking it in a variable speed drill and spinning the loop in the water passages.

On mine it was an old log style manifold and I could only do this with the end caps removed.

Once the crud is removed, you can clean out the rest with a pressure washer. It's messy but effective.

Once clean, you can see if there is enough iron left to reuse the manifold for a little while.