Sealing new gaskets on 9.8 merc

[britabroad]

I'm replacing the water jacket gasket, and exhaust plate gaskets on my 1985ish Merc 9.8.

Can I use Ultra-black RTV to seal the gaskets? The mating surfaces are a little rough from corrosion.

Thanks.

 

[dajohnson53]

Re: Sealing new gaskets on 9.8 merc

I'm replacing the water jacket gasket, and exhaust plate gaskets on my 1985ish Merc 9.8.

Can I use Ultra-black RTV to seal the gaskets? The mating surfaces are a little rough from corrosion.

Thanks.

I had the same question about my 1974 9.8 last year: http://forums.iboats.com/showthread.php?t=222937&highlight=gasket

I made the surfaces as smooth as possible, but it still leaked with the new gasket. It was recommended in that thread that I use #2 gasket sealer - which doesn't harden fully. I did, and have used it this summer without any leaking or problems. I used:
http://www.permatex.com/products/Au.../auto_Permatex_Form-A-Gasket_No_2_Sealant.htm

 

[britabroad]

Re: Sealing new gaskets on 9.8 merc

Thanks for getting back so quick - could you possibly let me know what the correct bolt tightening sequence is? (I don't have access to a manual)

Thanks.

 

[dajohnson53]

Re: Sealing new gaskets on 9.8 merc

Thanks for getting back so quick - could you possibly let me know what the correct bolt tightening sequence is? (I don't have access to a manual)

Thanks.

I'll try to get back to you. In general though, you need to tighten in several steps, and for each step, do a star or "every other" type pattern - like when you tighten lug nuts on a wheel. But I'll try to get at that manual in the next day or so.

 

[britabroad]

Re: Sealing new gaskets on 9.8 merc

Nudge - any chance you managed to take a peek at the manual?

 

[dajohnson53]

Re: Sealing new gaskets on 9.8 merc

Nudge - any chance you managed to take a peek at the manual?

Sorry - I'll dig out the shop manual and try to post before tomorrow - I just forgot!

 

[britabroad]

Re: Sealing new gaskets on 9.8 merc

No worries now - I tightened in a star pattern and seems to be holding nicely.

 

[dajohnson53]

Re: Sealing new gaskets on 9.8 merc

No worries now - I tightened in a star pattern and seems to be holding nicely.

I'm so sorry I didn't get to this. I am looking at my repair manual now and just for future inquiries, here is the tightening pattern and torque.

This is for a 1974 9.8 hp, so it may or may not apply to any other engine.


Here's the general tightening sequences for covers with bolts on each side:

left - right (as you're facing the cover)
8 - 7
4 - 3
2 - 1 - these are the bolts at horizontal centerline .
6 - 5
10 - 9

Note, some may only have 6 bolts.

One of my covers has an odd number of bolts with one in the center of the bottom edge of the cover:

left - right (as you're facing the cover)
4 - 3
2 - 1 - these are the bolts at horizontal centerline .
6 - 7 - 5

I hesitate to post torque specs because I think they are quite varied by year and also by specific model. Mine are all 88 or 99 INCH pounds. It is standard though to tighten in at least 3 steps in these patterns.