What it is?

[erniex]

On the top rear of the block of my '73 Merc850 IL4 there is a quarter size flat disk loosly but securely mounted in a horizontal position and held by a side bolt. It's behind the flywheel and right above #1 cyl. Is this a water pressure relief valve or what? Can't find it referenced in my manual.<br /><br />Thanks

 

[KCLOST]

Re: What it is?

Is it kind of like this? <br />The silver disk fixed in the recess?<br /><br />

 

[erniex]

Re: What it is?

Hi KC, no it is raised like it is inserted in the block with maybe a stem on it. Has engraved concentric circles on slightly rounded top. Your picture looks like a freeze plug and is fixed solid. This piece is raised slightly above the block surface, wiggles when moved by finger, and appears to be held in with a side pinch bolt.???<br /><br />Maybe I can post a pict. later if can't id.<br /><br />Thanks<br /><br />Thanks

 

[Laddies]

Re: What it is?

Its the serial number soft plug nothing more

 

[Laddies]

Re: What it is?

sorry I looked at the wrong picture

 

[Chris1956]

Re: What it is?

Ernie, There is a rubber motor mount in that general area. They are attached to the block with a horizontal bolt, and have a 1/4-20 fine thread screw attached to the top part of the rubber disk, which bolts to the top inner cowl. Sometimes the bolts seperate from the rubber mount. There is no water relief valve or thermostat on those motors!