Correct Riser Gaskets???

[whs28175]

Hi...

Have a Mercruiser 2004, 350 MAG MPI. Raw water cooled. Overheating issue.
Replaced water pump, all is good.

1) A mechanic did some work, and replaced the starboard side riser gasket.
I believe he *MAY* have installed the wrong one. There are two gaskets,
one between the manifold and the spacer. Both 'ports' on the gasket are full open. These ports are holes which allow water from the manifold to pass up into the riser. The second gasket, between the spacer and the riser is the issue.
Cannot get a straight answer. Is it the same as the first gasket, with holes
wide open? Or does it use the gasket with the 'reduced' hole? And if it uses the
reduced hole, does that hole go toward the front of the boat, or the back???

2) Does anyone know if there are 'baffles' in either the power steering fluid cooler or the fuel cooler that could hang up debris? Are these built like heat
exchangers with places that stuff could get caught? Or are they straight thru
tubes...

Any experience out there please pass it along..


Bill

 

[Bondo]

Re: Correct Riser Gaskets???

2) Does anyone know if there are 'baffles' in either the power steering fluid cooler or the fuel cooler that could hang up debris? Are these built like heat
exchangers with places that stuff could get caught? Or are they straight thru
tubes...

Ayuh,... They're Sorta straight thru, but Stuff still can Hang Up in 'em...

 

[achris]

Re: Correct Riser Gaskets???

...1) A mechanic did some work, and replaced the starboard side riser gasket.
I believe he *MAY* have installed the wrong one. There are two gaskets,
one between the manifold and the spacer. Both 'ports' on the gasket are full open. These ports are holes which allow water from the manifold to pass up into the riser. The second gasket, between the spacer and the riser is the issue.
Cannot get a straight answer. Is it the same as the first gasket, with holes
wide open? Or does it use the gasket with the 'reduced' hole? And if it uses the
reduced hole, does that hole go toward the front of the boat, or the back???...

Bill,

If the port side is undisturbed you can work out which gasket should be where by identifying them. Then check the starboard side to see it it matches... Use this drawing...

 

[Don S]

Re: Correct Riser Gaskets???

Have a look at this service bulletin.
http://www.boatfix.com/merc/Bullet/99/99_10.pdf

 

[whs28175]

Re: Correct Riser Gaskets???

Here's the latest..

Went to another dealer, who just finished a v6 with the same issue.

Merc is puzzled according to him. He did install new risers on the boat, as the claim is the new dry risers last only 5 years.

He did install the 'open' gasket on the bottom between manifold and spacer, and the restricted manifold between the spacer and the riser.

I guess I am lost as to why the need for the ristrictor....why limit the water going out the manifold, to the riser and out of the boat?

Don thanks for the info on gaskets, but that document does not apply to my boat. That is a wet riser document, mine has the new fangeled 'dry' manifolds.

So still looking for some answers as to my overheating issue.

Do have a new riser on order, and will install to see if it fixes the problem.
Will have to install new gaskets with it, just still wondering which to use.

Any ideas? Don't want to pull off the other riser, as that will also cost me $90 in gaskets to just look....

Bill

 

[whs28175]

Re: Correct Riser Gaskets???

Hold the phone...

After re-reading the gasket information provided, looks like I may be able to identify the gaskets by looking at the installed port side....will let all know what i found later today when i look at the boat, which is slowly rotting at the dock behind my house....errrrr


Bill

 

[whs28175]

Re: Correct Riser Gaskets???

The port side, still original, has the restrictor gasket between the riser and the spacer. The spacer has the full flow gasket.

Now the next issue. The starboard side had the restrictor hole towards the stern, the port has the restrictor hole towards the bow. WHich is correct?

Bill

 

[Don S]

Re: Correct Riser Gaskets???

I'm assuming from your posts, that you have the Dry Joint exhaust sytem, not the older style. If so, here is how they go together.

 

[whs28175]

Re: Correct Riser Gaskets???

Excellent! Thanks you have answered my issue. When parts arrive we will see if it gets fixed.

Thanks again.

Bill