Marinette Boat Forum

Ok here we go trying to help a fellow M owner and rebuilt his water pump and helped put his motor back in. He can not remember how all the lines ran. IT is a 67 house boat. My boat does not have the three lines coming off the sea rooster and I really don't understand the one going to the second thermostat on the side of the thermostat housing other than it would be a pressure release system??? also we both have the same water pump so why do they run two inlets to the bottom of his pump and only one on mine 73 is the year of mine and both are singles. Anyone know of a simple cooling system diagram ??
Thanks

The more I read and find info on this I think my boat has been wrong the last two years. Does every one have two inlets to the bottom on the pump from fresh water??

The single inlet water pump should be an engine with a closed (fresh water) cooling system. The dual pocket pumps are used on open (raw water) cooling systems. There was two versions of the raw water system, one with a mixing tee on the inlet side that hooks to the t-stat bypass, and the later one has no mixing tee and bypasses into the exhaust manifold. The later one does not use water outlet tube in the exhaust manifolds. The early one does. The early engines used a (now obsolete) screw in t-stat. Chrysler plumbing diagrams suck. They don't distinguish between outlets on the t-stat housing. Pictures might be good to determine what you have.
Do you have a water line that connects to the end of your exhaust manifold? Do you have one or two water lines connecting to the bottom of your manifolds?

Ok I have this from Marysville marine and its a little better than the manual ive seen. My big question is the main line coming into the back port as shown. I took photos but they did not come out good enough will be working on it again this weekend.

Here is the other boat I'm helping with and the only thing odd about this is the make shift hose reducer in the return line from the thermostat housing to water pickup. The slug of metal inside this has about a .250 hole.

Your friends boat sounds like it was overheating, so they put a restrictor in the bypass line. I have never seen it done there but chrysler had a TSB showing the use of restricting washers between the manifolds and risers/outlets. He probably has another issue that is being masked.

Which hose are you questioning on yours?

It is interesting that the factory diagrams you posted show the water tube in the manifolds only on the non mixing tee system. If you look at the papers supplied with the new barr manifolds, they show the opposite. I have only had good luck doing it the way barr recomends. If I follow what the chrysler manual says, they run hot.

Okay; I give up. What's a 'sea rooster'? (Was hoping someone else would ask, but...)

Jeff

The forum won't let you use the four letter word starting with c, but if he wrote it, seacock, he would have been fine.

Don't feel bad. I scratched a hole into my brain before I figured it out.