Thermostat Housing

[billwright43]

I have a 1985 Mercruiser 4.3 that has the type II thermostat housing. This housing is no longer available. My type II has six hoses with the poppets straight across. It can easily be replaced with the type I housing, but these have poppets also. I've read the type III housings are superior...presumably because of no poppets? Should I AND Can I swap to the type III housing that has 4 hoses? If so, is there info on conversion from type II to type III, specifically hose arrangement?

 

[Bondo]

Re: Thermostat Housing

Nope,....

Withoutthe poppets,...

Your motor will Overheat at idle....

 

[Gary H NC]

Re: Thermostat Housing

This is a case where Ebay is your friend...

http://motors.shop.ebay.com/_Boat-P...stat-housing_W0QQ_fxdZ1QQ_ptasZ1QQ_trksidZm39

 

[billwright43]

Re: Thermostat Housing

Thanks Guys,
I been watching eBay-but I have another related question. I've seen thermostat gaskets for the type I housing that allow varying amounts of water to bypass. Why iz dat? And which is recommended.
I also just thought about taking the thermostat out and leaving it out like I used to do with cars in the early 70's but was unsure about a marine engine.

 

[Maclin]

Re: Thermostat Housing

I can speak to the running without a thermostat. Don't! That housing controls how much water is avaiable to the engine's circulating pump as well as how much it will allow to bypass when the engine is not warm yet. The thermostat is an active player in this mechanically controlled system. The engine will not be cooled evenly in a raw water cooled setup without the thermostat, and the flow to the manifolds could be out of balance as well.

Even in automotive systems the water needs to be restricted in order for the coolant to have time to draw heat from the block and heads. Rarely is it a good thing to run without one.