Crusader manifold help

[Carver286677]

We have a carver 2866. Twin 305s quick question for some of you crusader experts on here these 3 newer pics are both raw water cooled motors without heat exchangers!! Why would they run the hose from the same exact thermostat housing on both 2 different places on the manifold on both of these engines both engines only have one hose going to them what is the purpose of going 2 different places with the same hose. First pic is are our motor style now wanting to up grade to new style

[km1125]

Not sure I understand your question.

Are you just talking about the bottom two pictures, and why one manifold is fed from the front and one fed from the back with the cooling water??

If so, that's probably a casting issue. They can make one casting that fits either side of the engine, so with the cooling port on one end, it ends up on the front on one side and the rear on the other side.

On the top picture, you need a distinctly different casting for each side of the engine.

[Oldie]

I too am a bit confused by the question, but will take a shot at it.

Photo 1 and 3 are the conventional ways of hooking up the manifold hoses. In photo 2 the fitting closest to thermostat could have damaged or stripped threads, and the owner plugged it and opted to use the other fitting. Also, in photo 2, using that fitting might make winterizing easier, depending on what equipment lives close to it it's installed.

My guess is that something happened that forced them to use that method, instead of going the conventional route.

[Viper]

I think I know what you're asking but in short, there is no simple answer. Where the hoses hook up depends on several variables such as the type of engine, cooling system design, water flow pressures, the angle of the engine, manifold design, whether the system is incorporating a cold or warm manifold cooling system, etc. While not always the case with older log type manifolds, the general rule was that water should enter the manifold at it's lowest point. Depending on the application, ensuring the entire manifold got sufficient water flow was a challenge at times and sometimes controlled with restricting gaskets, additional hoses, internal hardware or casting design, etc. This was common with log manifolds on older applications where the engines were mounted at an angle to achieve the proper angle of the prop shaft. Now that more and more engines are typically mounted level and the prop shaft angle is achieved at the transmission or V-drive, installing the input hose at the lowest point doesn't always apply, and the advent of the center riser design helped alleviate some technical cooling issues. Having said that, the application's use must be taken into consideration if the type of boating often puts the level manifold's attitude on an angle during use.

As long as the cooling system is keeping the engines and manifolds at proper operating temps, then I wouldn't worry so much about where the hoses are hooked up though you should confirm their location with a service manual. You don't want a cool running engine or manifolds. For proper efficiency, the engine needs to run at a certain temperature, and so do exhaust manifolds to ensure you don't accumulate condensation in the exhaust system.