Merc 5.7LX Riser Extension Gaskets ... Which to use??

[LiquidC]

I just got my 3" riser extensions, and I'm a little confused as to which gaskets to use & where. The manual shows a restrictor gasket on top, but the actual riser extension kit comes with open gaskets. Take a look at the screen shots.

Originally I had open gaskets between my mainfold & my riser. I would assume that I should install open gaskets to keep the flow of water the same as before, but the manual is telling me otherwise.

 

[81 Checkmate]

Re: Merc 5.7LX Riser Extension Gaskets ... Which to use??

I had the same issue with a 1" spacer.....

I looked up the original spec on my motor and ended up using open holes under the spacer and restrictor between the spacer and riser.

It had shown using a restrictor gasket from the get go. 1986 merc

Id say your kit covers both.

 

[LiquidC]

Re: Merc 5.7LX Riser Extension Gaskets ... Which to use??

Thanks 81 ... I'll have to get a set of restrictor gaskets.

The 3" extenstion also has the port for the hose from the thermostat, I can't find any info on where that hose should go to. Leave it connected to the riser, or move it to the extension??

 

[81 Checkmate]

Re: Merc 5.7LX Riser Extension Gaskets ... Which to use??

Make sure you are suposed to have restrictor gaskets.......Year of motor and so on.....

Now the hose.......Could leave it on the riser.....but your extension might get hot.

I had seen it in the manual with or with-out riser extensions and it showed how to hook that hose up.

 

[81 Checkmate]

Re: Merc 5.7LX Riser Extension Gaskets ... Which to use??

Just looked in the manual i have 89 to 92 and it does not say where to hook it up..... riser or extension....just say's to take out plug on extension to drain water.

The extensions should be cooled by water coming from the manifold....then the riser water is coming from the T-Stat.

Id keep it the same as you have now....Dont Hold it to me

 

[LiquidC]

Re: Merc 5.7LX Riser Extension Gaskets ... Which to use??

Thanks ... I looked in the manual I have, and it doesn't say where to land the hose. But on the flow diagram is shows flow coming up from the bottom of the manifold into the extension. So keeping the hose on the riser makes sense.