Cool air for carb under dog house

[1977 SILVERLINE]

I have been toying around with the idea of adding a fresh air fan to feed my carb on my 470. Should make it run stronger and hopefully help with warm weather vapor locking. Any opinions on this. Thanks

 

[alldodge]

I have been toying around with the idea of adding a fresh air fan to feed my carb on my 470. Should make it run stronger and hopefully help with warm weather vapor locking. Any opinions on this. Thanks

A fan can move enough air for the engines at idle and slightly above, but after that the engines will pull more air then the fan can supply. This is not an issue because of the open vents on the boat. The fan can help reduce vapor lock (if your experiencing this issue) by reducing some of the heat in the engine compartment. Vapor lock is caused by the fuel system components soaking up heat from the engine after shutting down. To reduce vapor lock you would need to slow to idle speed and let the engines cool, then keep the fan running for some time after shutting down the engines.

 

[floater212]

I have a 2005 rinker with a 350 mpi and I had A LOT of heat coming out from the motor compartment when I would get in there for skiing vests, so I added a 4" round vent from home depot to a side open locker in the walk through at the rear, then ran a 4" flex vent to the front engine area now when I open up the engine compartment for a ski vest change nowhere as hot as before, more like warm... I was going to add a 4" fan but to turn it on automatically would have been a pia looking for a pop thermostat at what temps on and what temp off, drove me crazy ( short trip ) this way was all free air movement and it works, noise is not any different, being it's in a cubby not like doing a vent right up front of doghouse, maybe if you keep it as low as possible it wouldn't be as loud...... hope that helps!

 

[JustJason]

You would not add a fan but instead add another blower motor. What you would do is have 1 blower motor installed so the flex tube is down in the bilge, and that motor would be orientated to suck any fumes out. And then the other blower motor would be orientated so that the flex tube points at the carb/manifold. And that one is set to blow. When you shut the engine down, turn on both blowers and let them run.

 

[Tail_Gunner]

http://www.iboats.com/Venturi-Vent-...06612048--session_id.220238402--view_id.38742

 

[thumpar]

Use the blower that you already have. I have learned to turn the blowers on when I start to slow down and keep them on for about 10 minutes after shutting the engine off. If it is a really hot day I will open up the hatch for a few. Mine will vapor lock too because of the VST but those methods solve the problem. A fan is not going to help with performance.