How long to run blower?

BF

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Apr 8, 2003
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1,489
So, in the real world, how long do you run the blower before firing up the engine of your I/O? A boating safety instructor recently told us it should be "at least 5 minutes", but that seems like overkill to me. For us, it's usually ~30 seconds (and I do mean 30 seconds, not 10 seconds that feels like 30 seconds). The blower does draw from down below the motor and works well... Blower is left on as long as the engine is running.<br /><br />What's considered acceptable/normal operating procedure? Has anyone actually had or seen an explosion from not using the blower properly?<br /><br />Brent
 

liquidasset

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Joined
Aug 23, 2003
Messages
21
Re: How long to run blower?

The manual on my boat(1987 Four Winns Liberator) says 4 minutes and whenever your below cruise. I try to stick to that for the first start of the day but after that maybe 30 seconds. Ive never heard of anyone getting blown up or anything. But I guess it depends on if your engine compartment accumulates a lot of fumes.
 

The Marine Doctor

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Jul 25, 2003
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Re: How long to run blower?

On really hot days it would be best to keep it on all the time as the engine compartment gets really hot. This will limit the chance of vapour lock.<br /><br />TMD
 

CharlesW

Petty Officer 1st Class
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Jul 8, 2003
Messages
335
Re: How long to run blower?

On our Chris Craft with a 5.0 Ford, I run it a couple of minutes, but....before I start the engine after the boat has been parked, I open the engine compartment, check the oil, look for any water or oil in the bilge and glance at the hoses and belts. That also vents the engine compartment of any gas fumes. When skiing or tubing the blower is left on all the time. That way I don't have to remember to turn it on before starting the engine after picking up people.<br /><br />Charles
 

MrBill

Senior Chief Petty Officer
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Aug 4, 2002
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Re: How long to run blower?

Today's newer fuel injected engines probably emit a lot less fumes than the older carb'd models, but why take a chance over a few minutes. Running the blower is critical for that seldom incident when fuel has leaked, more so than the routine fumes that occur from storage. I routinely run the blower 3-4 minutes while taking off the mooring cover, etc. And yes...sometimes I forget to run the blower when the boat has been on the dock for 20 to 30 minutes and I start up.<br /><br />Marine Doctor brings up a good issue...run the blower during engine use, particularly on hot days. I started this practice last year after severe vapor lock and have not had trouble since.<br /><br />Also...I have witnessed a flare up from starting an engine without running the blower...most importantly!!! Don't open the engine compartment under these conditions!!!
 

DBenja4148

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Aug 13, 2003
Messages
24
Re: How long to run blower?

Personally, I think 5 minutes is overkill. I usually open the hatch to check the usual items and if I don't smell gas I'll run the blower about a minute. When I get gas is to me the most important time to be careful. I'll run the blower from the time I dock until I leave after filling up.
 

crazy charlie

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May 22, 2003
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5,433
Re: How long to run blower?

I usually turn the blower on the moment I set foot on the boat.That gives me plenty of time to open up canvas and cabin and get things in order.Before you know it at least 5 minutes has gone by and the blower has been running ample time to start the boat.And YES I have heard of more than 1 case where an explosion has occured from fumes in the bilge. Charlie
 

popazog

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Joined
May 26, 2002
Messages
18
Re: How long to run blower?

I do run the blower for about 3 to 4 minutes before starting the engine for the first time in a given day... about a minute or two therafter during the stops and starts throughout the rest of my trip. I also don't turn it off while the engine is running and I keep it on while re-fueling. And although I did not witness this personaly I have seen video that a friend took of a boat on fire at a fuel dock... so it does happen.
 

Ralph 123

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Jun 24, 2003
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Re: How long to run blower?

From "Nautical Know How" Boat safety Certification training (www.boatsafe.com):<br /><br />Boats built after July 31, 1980 which contain power exhaust blowers in gasoline engine compartments must have the following warning sticker near the instrument panel:<br /><br />WARNING<br />GASOLINE VAPORS CAN EXPLODE.<br />BEFORE STARTING ENGINE OPERATE BLOWER<br />FOR 4 MINUTES AND CHECK ENGINE<br />COMPARTMENT FOR GASOLINE VAPORS<br /><br />Fueling<br />Proper fueling procedures are very important in preventing onboard fires. Gasoline vapors are heavier than air and can spread rapidly into enclosed spaces. You should check the bilges and all closed compartments for gasoline vapors. The sniff test is the most effective method for detecting fuel leaks.<br /><br />Fueling Precautions<br /><br />1. Secure boat to the dock.<br />2. Switch off engine(s). <br />3. Extinguish all open flames. <br />4. Do not use electrical switches. <br />5. No smoking. <br />6. Ports, hatches, and doors closed. <br />7. Portable tanks should be refueled ashore. <br />8. Make certain all passengers are ashore. <br />9. Determine quantity of fuel required. <br />10. Hold hose nozzle firmly against fill pipe opening. <br />11. Do not overfill. <br />12. Wipe up all spillage. <br />13. Open ports, hatches, and doors to ventilate. <br />14. Turn blower on for four minutes minimum. <br />15. Do the sniff test. <br />16. Start engines(s). <br />17. Re-board Passengers. <br />18. Untie from dock and cast off.
 

Lou C

Supreme Mariner
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Nov 10, 2002
Messages
12,193
Re: How long to run blower?

From what I have heard you should keep the blower OFF when fueling so it does not pull in vapors from the fuel dock. After you are done, open the engine hatch and run the blower for 4 min then start.
 

MFG197

Petty Officer 1st Class
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Aug 26, 2002
Messages
236
Re: How long to run blower?

BF, not to sound like a preacher or anything but it's people who get complacent and don't think warnings/rules/laws apply to them that end up in trouble. Take the guy who thinks that he is immune from the laws of static electricity and fills up his portable gas can in the bed of his pick up. We've all seen the results on the news.
 

lorax

Petty Officer 2nd Class
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Nov 3, 2002
Messages
134
Re: How long to run blower?

This falls under the catagory of "I know somebody who saw...."<br />I friend of mine who is really not prone to exageration, told be that he witnessed a, fuel in the bilge, related explosion. He said a woman was sitting on the cowling just after refueling the boat. They went to move it away from the dock and the cowling blew straight up. He said the woman landed in the water about 25 feet from the boat. She was relatively unharmed but a guy sitting in the seat next to the cowling had some pretty severe burns. He said the boat burned to the water line.
 

BF

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Apr 8, 2003
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1,489
Re: How long to run blower?

Thanks for the responses... <br /><br />One of the boats in our family is my Dad's I/O (I own OB's), and I was just curious whether we're fairly typical, or whether 5 min's before every start was S.O.P. It sounds like we're pretty typical. We don't refuel at a dock, but we are aware of the dangers associated with fuel vapours, particularly during fueling. We do have the engine compartment open prior to the first start (put in plug, check over everything) etc, then run the blower. We don't run the blower for 5 minutes if we've just shut down for a minute to help the kids into the boat after tubing etc... but we do run it for ~30 sec before restarting (usually blower is just left running)<br /><br />Turning on the blower while undoing the trailer tiedowns, or removing the cover etc is a good idea... easy enough to do, and it doesn't mean sitting at the dock for 5 minutes while there's a lineup at the launch.<br /><br />Anyway, thanks for the input(s)! We will continue to strive to keep all combustion within the engine!!<br /><br />Brent
 

cbjones10

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Aug 27, 2003
Messages
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Re: How long to run blower?

Has anyone seen an explosion from not blowing out the bilge. My brother-in-law, an avid speedboater for around 50 years has had his boat blow twice. Once was on starting. He apparently didn't blow long enough and suppects he had a loose wire on his starter that may have sparked. The second time, he had refueled and was just pulling away from the dock and had gone about 50 ft when it blew. No one was seriously injured either time but the first time blew him overboard. Both times he had scorched hair. I turn on my blower as soon as I reach the launching ramp and, if I have sat between runs for more than a minute, I blow out my bilge for a length of time depending on how long I have sat without running. My first start each time is in accordance with my warning label, 4 minutes.
 
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