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Old 06-11-2010, 08:51 PM   #33
Dave R
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Quote:
Originally Posted by Rattlesnake Guy View Post
Question about blowers. (Proof it's never too late to be a newbie)

When the engine is running, is the air being consumed and exhausted by the engine generally taken from the engine compartment? Does this consumption act to keep the engine compartment LEL (Lower explosive level) in check as the blower would do if on?

Gasoline needs to reach a concentration by volume of between 1.4% and a max of 7.4% to be explosive.
Gasoline powered inboard or I/O boats are supposed to be designed so that incoming air comes solely through the air inlet hose that ends in the bilge. On-plane, the engine moves more than enough air to keep the potential fumes from getting concentrated enough to be a problem. Off-plane, there's not enough air moving through the engine to safely evacuate fumes, so it's considered good practice to run the blower when not on-plane. Almost no one I know does this though.
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