Operating blower motor while engine running

In a current post about engine parts/function, Loren mentioned that he was advised by his mechanic to run his blower motor whenever the engine is operating. It had been my understanding that one should operate the blower motor before starting the engine (especially in a gas engine) to clear the engine compartment of any fumes, and perhaps occasionally underway to exhaust heat from the engine compartment.

I'm wondering why it would be necessary or adviseable to operate the blower motor all the time while running with the engine. Can someone clarify? What do you all do?

Thanks,
Frank

For a gasoline engine it should be obvious why you should run it. Gasoline fumes are extremely dangerous.

For a diesel, heat, blow-by, exhaust leaks are all things that can be vented out of the engine compartment with a blower. Your engine will run fine with or without it running. But if you have people in the cabin while motoring, an exhaust leaks could be dangerous.

It will also prevent engine smells in the cabin by creating a lower pressure environment in the engine compartment thus sucking in fresh air from other areas of the boat.

In a diesel class we learned that about 3 to 5% of the heat transfer from our sailboat diesel engines is calculated to be removed by direct radiation. And, on that note, keep the block clean of a buildup of dirt-encrusted oily material, as this acts as an insulator.
Advice was to always run the blower to remove heated air from the engine compartment.
:nerd:
Next, the engine compartment on most smaller sailboats is very confined and heat builds up in there quickly. This affects your alternator output and service life. Since we have no explosive gasoline vapors possible, our exhaust flex hose intake should be near the top and reasonably close to the alternator to suck out that rising heat.

Hope this helps,

Loren

Agree with the reasons given above. The continuous use of the blower makes a big difference when using the quarter berth. I rewired my engine panel to allow the use of the blower with the key switch OFF and I run the blower for at least 30 minutes after shut down.

One thing to consider is the type of blower you have. The small plastic axial flow fan that is usually installed is not intended for continuous operation. I replaced mine with the Jabsco "squirrel cage" blower.

Ray Rhode
S/V Journey
E35-III, #189

Thanks, guys, for that very helpful information.
Frank

Ray Rhode said:

Agree with the reasons given above. The continuous use of the blower makes a big difference when using the quarter berth. I rewired my engine panel to allow the use of the blower with the key switch OFF and I run the blower for at least 30 minutes after shut down.

One thing to consider is the type of blower you have. The small plastic axial flow fan that is usually installed is not intended for continuous operation. I replaced mine with the Jabsco "squirrel cage" blower.

Ray Rhode
S/V Journey
E35-III, #189

Click to expand...

I never thought of running the blower after I shut down the engine. I guess that is a difference of living in Maine as opposed to FL

Mid Engine Ventilation

I Run the Blower on the E35II Mid Engine continuously to get rid of heat from the engine. Have also added a 2"x 12" vent inlet in the front engine cover base to help with ventilation. The Mid Engine Design is isolated from the Hull ventilation and needs some help.
I also run the 12V Blower at 6V which provides plenty of exhaust out the stern vent and makes it a whole lot quieter.