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exhaust manifold and Riser and spacers

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3-legged-dog

Contributing Member
03, 350 Mag. Merc. 0m366996, Bravo III, running in bracklish water,

When should manifold, riser, 3" spacer or gaskets be replace?

Should all 3 on both sides be replaced together?

Replace parts should i go with Merc., Sierra or Barr?
 
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do i have a dry joint system? replace all pieces?
 
The more I look at this and compare parts on the web. i think i have a wet joint but my engine serial numbers says different, says i have a dry joint. If system is dry, can i just replace gaskets?
thanks
 
You have wet joints , it is NOT dry joint system. Manifolds about 6-10 years depending, same for the extentions. If your risers are the SS ones, they will outlast the boat.

Consider getting rid of that "quick-crack" drain system too
 
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I have just removed manifold and riser, inside thickness look really good. can they be cleaned up and reused or buy new?

and just replace the gaskets and new thru bolts? looking like my main gasket from manifold to block was in bad shape and 4 bolts were not snug. really loose.

what kind of sealant for the pipe fitting?
 
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3-legged-dog said:
I have just removed manifold and riser, inside thickness look really good. can they be cleaned up and reused? or buy new?

If the wall thickness is good (at the seawater transfer ports), a machinist can dress up the mating surfaces on a surface sanding machine.
If should not require more than a few minutes per surface!

If each component is clean and dry, he can also perform a Magnaflux check on each one.

I prefer to use the automotive Anti-Sieze or Never-Seez product for the manifold to cylinder head bolts. (for above water line apps only)



Lower exhaust unit = manifold
center exhaust unit = spacer/riser (not used in all applications)
upper exhaust unit = elbow
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Rick, if I could find a machinist in Wash. DC., his labor would be more than the parts. as I am considering just buying new rather than scrapping and dealing with heavily rusted parts. do you have a preference on aftermarket vendors?

the fitting on the manifold, plugs and pipes etc. has a red color adhesive on he the thread. what product is that?
 
Let me clear it up a bit, the single point drain works in theory but not in real world corrosion. Get aggressive with the blue drain plug in the plastic housing and it will crack the housing. There is nothing inside that plastic ball so copper or brass fitting can replace it. The reason the system fails is because the block drain fittings get clogged with rust and scale and do not drain. There 3/8 id hose compared to the 1/2 inch manifold drains. Failure to remove the quick connect hose at the engine and probe the opening to insure drainage is the only option. Failure to drain results in a cracked block.
The other killer is the so called engine flush systems. They do not allow the engine block to drain.
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DSCN4140%20-%20Copy_zpspmudx8r9.jpg
 
i just bought aluminum manifold, spacer and risers non-dry. new spark plugs as well. not sure if it the right purchase, cast iron parts look good, fitting thread all rusted tight. labor to clean up plus misc. parts on separate orders.

Spark plugs shown in the picture above all broke off inside the block, lower threaded case still inside. has that happened to you, what should i be looking for.
thanks
 
i dont drain the block, when i winterize i drain thru my 4 ports on my drainage system, then start engine for 2 mins. to push any excess water out. i will run Marine green thru a recycle system, 5 gallon bucket and bilge pump into the muffs for 15 mins or so. coolant will be hot 150 or so, if alarm comes on i shut down wait and restart. if water remains it is diluted. i did open that fitting after i drained my system using the 4 ports. no water was behind the open fitting.
 
3-legged-dog said:
i dont drain the block, when i winterize i drain thru my 4 ports on my drainage system, then start engine for 2 mins. to push any excess water out. i will run Marine green thru a recycle system, 5 gallon bucket and bilge pump into the muffs for 15 mins or so. coolant will be hot 150 or so, if alarm comes on i shut down wait and restart. if water remains it is diluted. i did open that fitting after i drained my system using the 4 ports. no water was behind the open fitting.
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1...... none of the above is advisable! https://www.amazon.com/review/R3BD7X6QC3KCFR/ref=cm_cr_pr_viewpnt
2...... the single point drain systems should undergo a campaigned re-call.


Do as any Non-Single-Point-Drain-System OEM service manual suggests...... Drain all seawater from the system!!!!!
And keep in mind that just plain ole Air will NOT freeze expand and damage our expensive cast iron components!

Add E/G (or the Pink RV stuff) if you need that "feel good" feeling...... but drain it again afterwords!






.
 
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i dont drain the block, when i winterize i drain thru my 4 ports on my drainage system, then start engine for 2 mins. to push any excess water out

A quick way to destroy the impeller

i did open that fitting after i drained my system using the 4 ports. no water was behind the open fitting.

If you didnt probe the opening it was corroded closed
 
He more I look at the pics its almost as if the motor went under water , way too much rust all over.
Are you sure your method didnt crack the manifold and the leaking caused the plugs to rust into the head?

You will have to remove the heads for them to be fixed
 
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Bt Doctur said:
i dont drain the block, when i winterize i drain thru my 4 ports on my drainage system, then start engine for 2 mins. to push any excess water out
Click to expand...
A quick way to destroy the impeller

Yes..... I certainly agree!

i did open that fitting after i drained my system using the 4 ports. no water was behind the open fitting.
Click to expand...
If you didnt probe the opening it was corroded closed

I fully agree....... All ports should be probed as to ensure complete draining!
Click to expand...
 
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