Replace tstat housing,hole inside

[crazy charlie]

Still troubleshooting rising temp at idle. 5.0xl mercr i/o 1988.I removed the large hose coming off the circulator pump to the tstat housing.Looking in the large inlet with the hose off of the housing, there is a small hole about the size of a small marble straight inside the inlet hole about 2-3 inches inside.I am not sure if it is a large hole closing due to rust and corrosion or a small hole occuring due to corrosion or galv/electrol etc..Anyone know if this sounds right or not.????Anyone???? Charlie

 

[chiefalen]

Re: Replace tstat housing,hole inside

You mean the bypass hole? Than when the t-stat opens the water goes down a large hole.

 

[crazy charlie]

Re: Replace tstat housing,hole inside

No,it is off to the side of where the tstat is.Is is a rather large housing and the circulator pump connects to the lower section.

 

[Don S]

Re: Replace tstat housing,hole inside

Mercuriser used 3 different looking thermostat housings in that era. Can you post a picture of the one you have, or CLICK HERE and download the OEM manual (about 500 MB, big file) and give a page number showing the one you have.

Or, click here and choose the one you have.

 

[crazy charlie]

Re: Replace tstat housing,hole inside

Thanks Don.It looks like the one on page 569 that states "redesigned".Looking in the stbd side where the circu pump hose goes.Small hole in bottom of what looks to be a wall.It has a pipe thread in the underside for sure and tballs.Charlie

 

[Don S]

Re: Replace tstat housing,hole inside

Look at page 577, I think it shows the hole you are referring to, if not, let me know.

 

[crazy charlie]

Re: Replace tstat housing,hole inside

thanks again Don.If you are referring to the cold water arrows running along the bottom ,right after the only arrow with the stright and upturned end.Then I think thats the hole.Is that the one you meant??charlie

 

[Don S]

Re: Replace tstat housing,hole inside

 

[crazy charlie]

Re: Replace tstat housing,hole inside

Yep,thats the one!! So now that I know it is supposed to be there,I will poke around and see if it has closed up some with rust.It DID look a little small for a water passage.Thanks again Don.