Twin 1998 Merc 350EFI - Riser temps

[Strecker25]

Hi all, first post here but I've lingered for some time for info..so thanks for all the reading up to this point

We have a 1998 290DA with twin 5.7EFI Mercs, alpha drives. I just purchased the boat early may so we immediately did risers/spacers/manifolds as a precautionary measure as the surveyor detected high temperatures on both stbd sides of the engines.

The old iron was pretty bad, so I'm glad we did it but I still have some pretty hot stbd risers when comparing to the port side. I just bought an IR gun, so I don't have any hard numbers yet but I will say after a run I can lay my hand indefinitely on the port elbows, but have to pull away after 3-5 seconds on the stbd sides.

Y pipe shutters looked fine when we had them open, and I have not smelled any melting rubber so my concern is really just the difference in temp.

Sorry for that long winded into..on to my main question. I followed the bulletin here : http://www.boatfix.com/merc/Bullet/99/99_10.pdf which led me to believe I should use OPEN gaskets (4 open slots) on both the manifold to 3" spacer connection as well as the spacer to elbow.

My engine SN are OL041938 and OL041969

Did I interpret that right in using all the open gaskets or should there be restricted gaskets between the spacers and elbows? Our motors have single water connection on the bottom of each manifold 90*.

 

[alldodge]

Hi all, first post here but I've lingered for some time for info..so thanks for all the reading up to this point

We have a 1998 290DA with twin 5.7EFI Mercs, alpha drives. I just purchased the boat early may so we immediately did risers/spacers/manifolds as a precautionary measure as the surveyor detected high temperatures on both stbd sides of the engines.

The old iron was pretty bad, so I'm glad we did it but I still have some pretty hot stbd risers when comparing to the port side. I just bought an IR gun, so I don't have any hard numbers yet but I will say after a run I can lay my hand indefinitely on the port elbows, but have to pull away after 3-5 seconds on the stbd sides.

This isn't an issue, one side will always be hotter then the other, its just the way water flows more easily to the port side over the starboard.

Y pipe shutters looked fine when we had them open, and I have not smelled any melting rubber so my concern is really just the difference in temp.

Sorry for that long winded into..on to my main question. I followed the bulletin here : http://www.boatfix.com/merc/Bullet/99/99_10.pdf which led me to believe I should use OPEN gaskets (4 open slots) on both the manifold to 3" spacer connection as well as the spacer to elbow.

My engine SN are OL041938 and OL041969

Did I interpret that right in using all the open gaskets or should there be restricted gaskets between the spacers and elbows? Our motors have single water connection on the bottom of each manifold 90*.

:welcome: to iboats

You should use open gaskets but yours don't look like what was in your bulletin they look like this one

 

[Strecker25]

Thanks! Yep, those are the ones. I used them in all places, so between the manifold and 3" spacer as well as between the spacer and elbow.

I'd hoped I interpreted it correctly, but I'm always paranoid when it comes to the exhaust system so I wanted to make sure it was right. I'll still monitor the temps periodically but I'm assuming if rubber isnt melting and I don't see any steam that things are generally ok.