New Mercruiser OEM Manifold and riser. Painted?

[Jiminthekeys]

I just got my new mercruiser brand manifold and riser in for my 3.0L. I was a bit impressed they came with all the gaskets, new fuel pipe, manifold fittings etc. Could have save 25 buck or so if I new that! guess I have some spare parts to slap some new gaskets on it next year anyway...

My quest is the new manifold and risers came painted. I know this is supposedly some kind of special corrosion protective coating that mercury put on but it looks like the mating surfaces on both the manifold and riser are painted. THey are black anyway... If it is a paint coating on the mating surfaces it is probably very thin because it looks like it would not inhibit a good seal with the gaskets at all. Should I sand the mating surfaces regardless to make them shine? Or would i be find just re-assembling them with the new gaskets and hardware since they are brand spanking new and super smooth?

Also the brass plug fittings for the maifold have a red thread coating on them. Is this already pre coated with the perfect seal? Or do I need to still apply perfect seal? (not sure if the red i'm looking at on the threads is already perfect seal or if it's lock tite or something).

And I also plan on doubling the manifold to head gasket up as stated in my previous thread because of the little bit of corossion pitting I had going on there before. I assume that may not be neccessary but I guess it couldn't hurt either?

Thanks!

 

[tpenfield]

Re: New Mercruiser OEM Manifold and riser. Painted?

don't kid yourself about the paint . . . it is nothing special.

The red sealant should do the trick and as long as the paint is even, the gaskets should have no problem mating.

 

[NHGuy]

Re: New Mercruiser OEM Manifold and riser. Painted?

I just did my manifolds a couple of weeks ago, elbows were OK. I left the finish on the mating surface and torqued the bolts per my manual. It did not leak at all. I did use some perfect seal, right over the red stuff. It's probably not essential but I really like the way perfect seal works.

I do not recommend using extra gaskets. They are not designed to be used that way so you are chancing problems. But that's your choice.
I do recommend milling your mating surface or it will corrode through quicker. The gasket can't conform and properly clamp to the uneven opening.

 

[Jiminthekeys]

Re: New Mercruiser OEM Manifold and riser. Painted?

ok thanks, I will just leave the paint on the surfaces then since they are new and smooth. Also will just use a single gasket from the head to manifold part. I have some perfect seal on order so I'm going to wait till that gets here before I install it all. ...Not looking to pull the head off and have it milled or re-surfaced right now though. I figure when I inspect next year if it looks worse or I have exhaust gas leakage in the interim I will then have it re-surfaced or replace it.... Strapped for cash now after dropping it on the new manifold and riser and I figure it will be sealed good for water intrusion which is most important.

 

[Jiminthekeys]

Re: New Mercruiser OEM Manifold and riser. Painted?

Has anyone used the fuel line that comes with the new manifold?? My existing fuel line is fine and the new one is a little different. My old one goes from a rubber fuel hose to a short stainless fuel tube to hook into the carb. The new one is a long single piece stainless tube.

I guess if I don't use that I can ebay it or something.

 

[muc]

Re: New Mercruiser OEM Manifold and riser. Painted?

I have always removed the paint -- seem to remember the instructor at Merc School recommending it.
I also use perfect seal over the red coating. The important part is to not over tighten them. It’s much easier to tighten them a little more if they leak than it is to buy a new manifold if it cracks --- and yes they can crack much easier than I would have thought.
I also recommend against 2 gaskets – double gaskets cause way more problems than they cure.
I think you should use the new fuel line. While (correctly rated) rubber fuel line isn’t bad the problem is that in that application it is usually installed over a non-barbed steel line and that is bad. My guess is that your engine originally came with a one piece fuel line because MerCruiser thinks that is safer.

 

[Jiminthekeys]

Re: New Mercruiser OEM Manifold and riser. Painted?

Thanks for the tips. The fuel line that is in there now is what it came with from the factory. rubber fuel line crimped to a metal tube about 6 inched or so in length with the fittings. The one that just came with my replacement merc manifold is all metal about 2.5-3ft in total length with fittings on each end. Maybe mercrury changed this somewhere down the line? My engine is a 2007 3.0L.

I have always removed the paint -- seem to remember the instructor at Merc School recommending it.
I also use perfect seal over the red coating. The important part is to not over tighten them. It’s much easier to tighten them a little more if they leak than it is to buy a new manifold if it cracks --- and yes they can crack much easier than I would have thought.
I also recommend against 2 gaskets – double gaskets cause way more problems than they cure.
I think you should use the new fuel line. While (correctly rated) rubber fuel line isn’t bad the problem is that in that application it is usually installed over a non-barbed steel line and that is bad. My guess is that your engine originally came with a one piece fuel line because MerCruiser thinks that is safer.