Fresh Water Cooling/Gasket placement

kellydee · Mar 17, 2007

Just got my BRAND NEW Merc 5.7.I'm installing a FWC system (Full kit,block & manifolds). My risers have the 1.7" spacer blocks on them and I need to know if I should put the "block off" gaskets on top the spacer blocks so they are basicly fresh water cooled or should theese "block off" gaskets be placed under the spacer blocks making them raw water cooled which probably means replaceng the spacer blocks whenever risers are replaced?.)

Don S · Mar 17, 2007

Re: Fresh Water Cooling/Gasket placement

BRAND NEW Merc 5.7 could mean different things to different people. Is this a brand new bobtail engine, or a new long block. Is it carbed or EFI, does it have standard exhaust or the new Dry Joint exhaust manifolds and risers? Is your FWC kit and OEM or an aftermarket kit.

Thought this would be an easy question didn't you?

kellydee · Mar 17, 2007

Re: Fresh Water Cooling/Gasket placement

Hey Don,I spoke with you about 3 weeks ago and put my motor on hold.Rember?Anyways,Just got my bobtail,carborated,dry joint,after-market(San-Juan)cooling.

kellydee · Mar 17, 2007

Re: Fresh Water Cooling/Gasket placement

Sorry I wasn't here when you responded.I thought I was done working on the boat for the night but,found myself back in the shop for another hour.Been waiting awhile and now that I've got her I'm ready to get on with the project so I'm ready for halibut in May.

kellydee · Mar 18, 2007

Re: Fresh Water Cooling/Gasket placement

I'm back this morning still looking for answers.Anyone?

Don S · Mar 18, 2007

Re: Fresh Water Cooling/Gasket placement

kellydee · Mar 18, 2007

Re: Fresh Water Cooling/Gasket placement

Sorry again for the slow response.got hung up on phone..I'm gonna go look at mine again.I think mine may look a little different from the pic you provided.The hoses look like they are in different locations.CRAP,I need to learn to type with more than 2 fingers for this.Takes me way to long to get it out.

Don S · Mar 18, 2007

Re: Fresh Water Cooling/Gasket placement

Just follow the instructions for the gaskets. Your hoses will be different as you don't have a Merc FWC kit.

kellydee · Mar 18, 2007

Re: Fresh Water Cooling/Gasket placement

OK,mine only looks different because I have 1.7" spacer blocks instead of the 6" shown in the pic.In my instructions,it says to remove the plug (E) from the exhaust man. and put nipple there for exhaust man. outlet.My instructions do not include spacer blocks.I can see from the pic that the exhaust man. outlet is actually comeing out of the spacer block instead.I think this is what I need to do and just leave the plug in the exhaust man.. Right? Also,can these gaskets be re-used,or one time shot ? These are the $ 80 gaskets I spoke of a couple weeks ago (pair).

kellydee · Mar 18, 2007

Re: Fresh Water Cooling/Gasket placement

Don said:
Just follow the instructions for the gaskets. Your hoses will be different as you don't have a Merc FWC kit.

There were no instructions for the gaskets as they only provided the block-off gaskets.I had to purchase the full-flow ones seperately.There just wasn't any mention of spacer blocks,full-flow gaskets or putting the exhaust man. outlet hoses on the spacer blocks instead of on the exhaust man. if spacer blocks were used. As I said NO mention of spacer blocks.So,should I change this and put the exh. man. outlet hoses on the spacer blocks instead as shown in the pic you sent ? Even though I don't have a Merc brand kit,the hoses should still run to/from the same place,correct?

kellydee · Mar 18, 2007

Re: Fresh Water Cooling/Gasket placement

Another thing,the hoses provide are not pre-formed so,it's not like they wont fit if I put the outlets on the spacer blocks instead of on the exhaust man..Kind of makes more sense that they would be on the spacer blocks so as to let the coolant flow a little more through the spacer blocks rather than exiting just below them from the exh. man..

kellydee · Mar 18, 2007

Re: Fresh Water Cooling/Gasket placement

I have been using Oatley brand " pipe joint coumpound" with teflon on my fittings. Is this OK ? It is for plumbing fittings and rated for liquid temps to 500degrees.Also used for steam and nat gas pipes.

kellydee · Mar 18, 2007

Re: Fresh Water Cooling/Gasket placement

Still waiting for answers on gasket re-use(this is new motor) and thread sealant.hose location.Please tell.Also,the FWC kit from San Juan Engineering eliminates the lifting eye one the thermostat housing . Where will I lift (front & center) for alignment?

Don S · Mar 18, 2007

Re: Fresh Water Cooling/Gasket placement

First of all, what is this 1.7" spacer. Mercruiser has a 3" or 6" extension that I know of, and assumed you was meaning the 3" extension. Shame on me for assuming. Got any pictures of these spacer blocks
If this 1.7" extension/spacer block is a San Juan Eng. part, then I don't have any idea what it is.
The gaskets, like any gasket shouldn't be reused,

kellydee · Mar 18, 2007

Re: Fresh Water Cooling/Gasket placement

These are 1.7" spacers.The new elbows on this motor are a little taller than the ones on my 96 5.7.I think 4.3" of rise. + 1.7" spacer = 6" total rise.My old were 3" rise + 3" spacer blocks.They also exhaust at a steeper a steeper angle than the old.If you go to the Merc Parts Express and put in my serial # you will find these.I think even the exhaust elbows are a different part # as well(to match the different angle of the risers).

kellydee · Mar 18, 2007

Re: Fresh Water Cooling/Gasket placement

kellydee said:
These are 1.7" spacers.The new elbows on this motor are a little taller than the ones on my 96 5.7.I think 4.3" of rise. + 1.7" spacer = 6" total rise.My old were 3" rise + 3" spacer blocks.They also exhaust at a steeper a steeper angle than the old.If you go to the Merc Parts Express and put in my serial # you will find these.I think even the exhaust elbows are a different part # as well(to match the different angle of the risers).

Oh yeah,This is all Merc Factory.motor.

kellydee · Mar 18, 2007

Re: Fresh Water Cooling/Gasket placement

Don, Do you know where I can find a diagram like the one you sent but with these 1.7" spacers instead?

kellydee · Mar 18, 2007

Re: Fresh Water Cooling/Gasket placement

kellydee said:
kellydee said:

These are 1.7" spacers.The new elbows on this motor are a little taller than the ones on my 96 5.7.I think 4.3" of rise. + 1.7" spacer = 6" total rise.My old were 3" rise + 3" spacer blocks.They also exhaust at a steeper a steeper angle than the old.If you go to the Merc Parts Express and put in my serial # you will find these.I think even the exhaust elbows are a different part # as well(to match the different angle of the risers).

Click to expand...

Oh yeah,This is all Merc Factory.motor.

What a dumbass,here's the # OW689856

kellydee · Mar 18, 2007

Re: Fresh Water Cooling/Gasket placement

How do I add pics?

Don S · Mar 18, 2007

Re: Fresh Water Cooling/Gasket placement

The 1.7" extensions must be new this year. I have the service manual for the Dry Joint exhast system and there is nothing in it about the 1.7" extension.
Just pretend that the picture I showed you is drawn out of proportion and the extension is only 1.7". The gaskets all go the same, and the plumbing should be the same.
The Antifreeze side goes into the manifold from the bottom and comes out the extension outlet. Sea/raw water goes into the riser above the extension and out the exhaust where it mixes with the exhaust.
The gaskets will still fit as shown in the picture above.

Fresh Water Cooling/Gasket placement

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