mercruiser 470 riser gasket

[jabfd]

hello
Iam having problems getting my riser gasket to seal up right i put a new gasket and it still leaks i even tried two gasket
has anybody ever tried rtv sealant or any other kind ? And had good luck. I know merc says dry but thats not working for me thanks in advance

 

[Bondo]

Re: mercruiser 470 riser gasket

hello
Iam having problems getting my riser gasket to seal up right i put a new gasket and it still leaks i even tried two gasket
has anybody ever tried rtv sealant or any other kind ? And had good luck. I know merc says dry but thats not working for me thanks in advance

Ayuh,.... How bad is the gasket surface of the manifold,..?? the riser,..?? post pictures,....

Did ya Clean 'em to clean metal,..??
Are they Flat,..??

 

[jabfd]

Re: mercruiser 470 riser gasket

cleaned them everytime suface doesnt look bad also if i torque it to spec leaks bad if i crank it down it gets better but still leaks i will try to take pics

 

[Bondo]

Re: mercruiser 470 riser gasket

cleaned them everytime suface doesnt look bad also if i torque it to spec leaks bad if i crank it down it gets better but still leaks i will try to take pics

Ayuh,... My guess is, the gasket surfaces of the manifold, 'n riser ain't as good as ya think they are,...

They Must be clean, flat, 'n smooth,...

 

[fishrdan]

Re: mercruiser 470 riser gasket

^^^ Yup, I'm with Bondo...

Also, what type of gasket are you using, green/white paper gasket or grey/silvery metalized gasket?

 

[jabfd]

Re: mercruiser 470 riser gasket

^^^ Yup, I'm with Bondo...

Also, what type of gasket are you using, green/white paper gasket or grey/silvery metalized gasket?

iam using genuine mecruiser part its gray

 

[jabfd]

Re: mercruiser 470 riser gasket

i read that people use perfect seal or rtv black or avaition sealant has anybody ever use these ?

 

[Capt. Click]

Re: mercruiser 470 riser gasket

Hey, my exhaust manifold does not have a baby but slick surface. I used some high heat silicone on mine to help with the unevenness of the EM. The riser was brand new. I did not use a lot , used something flat and scraped off the excess leaving only some in the low spots on the EM. I have not had problems at all with mine. Be sure the ridges between the water jackets and the exhaust chamber are not corroded to where there is not enough surface left on the EM for the riser to seal. I had one that leaked and one of the ridges was leaking due to small thin area for the riser and EM to seal. Water will run on to the exhaust valves if it leaks into the exhaust chamber. Water can also go across the piston and into the intake manifold while running. I thought I had a bad head or intake manifold. Nope it was the EM and riser not sealing due to a corroded EM.

"GET'EM OFF THE BOTTOM"

 

[fishrdan]

Re: mercruiser 470 riser gasket

The residue of the silver metallic mercruiser gaskets can get burnished into the casting while you're trying to scrape it off, and kind of appear like "metal", but it's the remnants of the gasket. Using a straight edge should reveal where the residual gasket is still stuck, (if it is) or look for a highly polished section that looks different than the rest of the casting's machined surface.

The Mercruiser riser gaskets are supposed to go on dry (but I use Permatex aviation sealant anyway).

Is there any pitting on the machined gasket surfaces, pitting that leads from the water jacket to the exhaust passage?

 

[jabfd]

Re: mercruiser 470 riser gasket

thanks to everbody you responded i was able to use a file to clean up a few area and also use aviation sealer light coat on each side of gasket pressure tested and is holding. Now before i put e/m back on the engine i pressure tested the engine and was losing pressure but i will post that on a new thread thanks again

 

[blkzoe]

Re: mercruiser 470 riser gasket

Has anyone tried Permatex Hi-temp Copper based RTV for this application (problem). Temperature range -75F to 700F intermittent
Suggested Applications: Exhaust manifolds/headers, valve covers, oil pans, timing covers, water pumps, thermostat housings


Permatex 81878 Ultra Copper Maximum Temperature RTV Silicone Gasket Maker, 3 oz. Tube : Amazon.com : Automotive