Hey guys, working on a 1992 baja outlaw 24 with a mercruiser 7.4 454. The heat exchanger was removed and a GLM thermostat housing with the two check balls at the T was installed in place of the previous housing.




The cooling lines were re routed eliminating the use of the (top) manifold hoses ( capped off) , while utilizing the bottom of the manifold hoses and the top riser hoses. from my understanding the thermostat cover ports should run to the bottom of the manifolds, and the T with the "check balls" should run to the top of the risers, is this correct? it does have the raw sea water pump. if this system was changed from a closed cooling setup by removing the heat exchanger, does that require me to use a different style of gasket between the riser and manifold with (open) holes? i wont be able to pull the risers until tomorrow but i have a suspicion that they will be blocked off gaskets from the previous cooling setup. (stock merc manifolds)

any help is appreciated, i don't know a alot about boats just trying to learn along the way, if i didn't explain things properly i can try and go further in depth. thanks in advance!

i wasn't able to post any pictures due to not having 10 posts.

Do you have spacers between manifolds and risers ?

no spacers between the riser/manifold.

Here, if like your tstat hoousing, this should help:
Check balls go to risers

riser gaskets should look like this. Not the type with 4 equal slots.

i actually have a different type of housing, similar to that but wonky looking compared to the one you posted (brass cup seat type). confirming the check balls go to the risers is a huge plus, thanks. ill see tomorrow which gaskets are currently installed and buy new gaskets of the appropriate type. this all stemmed from chasing an overheat in the left manifold/riser while running on muffs, it seemed like the water had nowhere to go due to things being routed incorrectly after the exchanger was removed. water did pump out of both exhaust tips though ( with thermostat removed)

You’ll have to replace riser gaskets anyway, when you remove.

This what you have ?

1. 

1. 

yes this is what i have

Mercs supplier of old style check ball, diag i showed, above post#4 supposedly stopped, supplying those. Merc’s new replacement housings look like the GLM above. And the real old merc stuyle

This is diag :