Bilge Blower install help

Rscottdds · #1 10-29-2013, 01:37 PM

My son just picked up a 88 I/o V20. The engine is pulled and being rebuilt. There isn't a blower in there at the present. I don't see a place for the exhaust hose either. Where is the blower normally placed and is the hose just routed up to the port or starboard vents? Thanks for any help.
-Robert

Destroyer · #2 10-29-2013, 02:19 PM

IF there is a bilge blower (lots of IO's don't have them) the placement of the hoses is really up to you. Normally you would see two vents on your gunnels, one on the port and one on the starboard side, towards the stern, just before the transom. One will have the vent vanes facing forward, the other will have the vent vanes facing rearward. The idea being that as you move through the water the air will enter through the forward facing vent and exit through the rearward facing ones, thereby venting your bilge automatically. Most powered bilge blowers exhaust through the rearward facing vents. But the decision as to where to place them is entirely up to you. The idea of course it to make sure that your bilge is vented of any explosive vapors before you start your engine. Since most modern engines have fuel injection now, the chances of a harmful build up of gas vapor are slim at best. Baring leaks in your fuel system, (at which point you should NEVER take your boat out on the water) there's really no place for the vapor to come from. I know that a lot of people will disagree with me, but when I had an I/O powered boat I never bothered with a bilge blower. All I did was lift the engine hatch before trailering the boat to the launch ramp. I figured that any vapor that might have accumulated would be long gone by the time I got to the ramp. Since there was never an explosion, I'm guessing it was a good decision. Understand, I'm not saying bilge blowers don't have their place, I'm just saying that with normal, prudent, safety precautions I think their usage is minimal at best.

Rscottdds · #3 10-29-2013, 02:48 PM

Both of the vents on this boat face backwards. My bass boat has one forward and one backward. The v20 will be an ocean boat though and I think I'd rather keep them facing the way they do so salt water spray doesn't get channeled into the engine compartment.

The way this boat will be used it will be started multiple times a day and the thought of lifting the engine hatch each and every time just doesn't appeal to me. I've seen a few pictures of what can happen when there is an explosion. Not a pretty site. If we are going to put one in now is the time as I can't use the boat anyway.

Of course the first I/O my family had when I was young didn't have a blower (not sure any boats did back then) and it didn't blow up. Easily could have though as I did have an uncle pump 30 gallons into the bilge through a rod holder once.

-Robert

macojoe · #4 10-29-2013, 03:49 PM

,my 75 had them on top of the gunnels, one backward one forward, but no worry about water that far up!

phatdaddy · #5 10-29-2013, 04:02 PM

i was at the marina one day waiting to get gas, holding on the sea wall. there was a sea ray i/o tied up at the pumps. guy comes running down to move it, jumps in, hits the key, boom. his buddy was sitting on the hatch cover. threw him about 15 feet in the air and in the water. nobody hurt, mostly flash & noise, but it made an impression on me.

cfelton · #6 10-29-2013, 08:07 PM

My 77 has three vents, one in the center facing forward and two facing to the rear. My blower is mounted below the one facing to the rear on the starboard side. I usually open the engine cover before starting and run the blower in extremely hot weather. It seems to keep the engine cooler. In N.C. its a law, you gotta have a working blower on a I/O boat. My vents have large hoses that go down into the bilge.