Engine Compartment Cooling

[duckman]

Greetings, I have a Century 4500 LX with a Merc 7.4L and Bravo I... it has a VERY large engine compartment that seems to get Aweful hot... I was thinking I could increase performance by ducting air from outside directly to the flame arrester, and help keep the compartment cool with some duct hoods...

 

[f_inscreenname]

Re: Engine Compartment Cooling

Sounds like a plan. Just be sure you dont duct any water to your flame arrester. It is real easy to get water in the carb (not only wake,think about rain). Boats sit at weird angles. I am sure you can find posts here where water (some how)got into the motor and now they have problems.

 

[Walter]

Re: Engine Compartment Cooling

I rigged an auxillary blower to come on 20 seconds after I've started the engine. It runs full time and really helps keep the engine compartment flooded with fresh air...especially at slow speeds. This blower pulls fresh air from the "intake" louver...and blows across the engine. It's in addition to the primary blower which pulls air from the bottom of the bilge and pushes it outside.<br /><br />Walt

 

[duckman]

Re: Engine Compartment Cooling

I like the blower idea! I think I could do a "ram" air induction system... I've been thinking about the water issue... I'll have to do some testing and see what reduces engine compartment temp the best... but the blower sounds like a real workable idea...

 

[duckman]

Re: Engine Compartment Cooling

An old racer's rule of thumb says that every 10 degree F. increase in intake air temperature decreases horsepower by about 1 percent. If the air inside the engine compartment is 30 degrees hotter than outside air (a conservative estimate), you're already 3 percent down on power.

 

[Walter]

Re: Engine Compartment Cooling

It would be interesting to know the air temp inside your engine housing after running at operating temp for a while. Then, after you've made whatever changes you plan to do, I'd be curious to know how much the temp drops.<br /><br />Good luck...and keep us posted.<br /><br />Walt