blower or blow up?

[dalt1]

Where does this said fuel vapor come from?

Leaky fuel line fitting, cracked fuel line, leak in fuel tank. Unless you know exactly when you may get a leak, I would use blower EFI or not.

[Faceplant409]

There was a picture of Jill's (skibabe? from Aus.) boat that burned to the water line on MBO years ago. Scary stuff.

[MadDogMike]

My old '97 VLX had an automatic blower that turned on below a certain RPM. Interesting that they went away from that.

[nuttyskier2002]

Many years ago I had an old '59 Chris Craft woody. I bought the boat when it was in pieces and was someone else’s project. I worked on it for several years refinishing the wood, getting the upholstery re-done and rebuilding the engine. When all was done I launched it in Fish River near Fairhope Alabama. I kept it at the little Marina there called Aney's. One evening me and a friend were taking a ride when all of a sudden the boat just died. It had never done that before running at cruising speed. I almost reached down to the key to give it a try at restarting. Something told me,....WAIT! Better check things out. I opened the engine hatch and was nearly knocked on my @ss from the smell of gas fumes. My bilge had about 2 inches of gas and it was still leaking. It didn't take long to find the problem. My fuel line (flexible steel braided) had come loose from the suction side of the fuel pump. There was a hose clamp there that I had failed to tighten when putting things together on the engine. I reattached the line and tighten. I then pulled the drain plug and allowed fresh water to flood the bilge while running the bilge pump (yes I know,... bad for the environment,....don't tell the EPA). I did this until I new it was safe to restart the boat. Needless to say,... we could have blown ourselves sky high that day. So what am I getting at? I don't take any of my safety gear for granted. USE THE BLOWER! Carry a fire extinguisher and everything else you are required to have.

[UWSkier]

I always run it for the first start of the day or anytime the boat has been sitting for more than 20 minutes or so. If taking a slow speed cruise, I'll cycle the blower on and off every few minutes. It's true that fuel vapors are heavier than air and will settle down into the bilge. This is why the blower intake should be mounted low in the engine compartment.

[SacRiverRat]

Where does this said fuel vapor come from?

Leaky fuel line fitting, cracked fuel line, leak in fuel tank. Unless you know exactly when you may get a leak, I would use blower EFI or not.

I'm just asking because logically, I can't figure out what it really does.. If you have a pool of fuel in your bilge, then running the blower isn't going to fix that.. or make any real impact?

I know this is one of those things, and real easy to say "just do it to be safe".. yea yea... I get that, I'm just trying to figure out what is really going on, and what happens when we run the blower.

I see no reason to run the blower after towing the boat to the lake - everything should be more than sufficiently blown out. I could see if the boat has been sitting for a long while, and some vabors have accumulated.. but if run, or towed recently.. should be pretty blown out. no?

[dihrdskir]

Where does this said fuel vapor come from?

Leaky fuel line fitting, cracked fuel line, leak in fuel tank. Unless you know exactly when you may get a leak, I would use blower EFI or not.

I'm just asking because logically, I can't figure out what it really does.. If you have a pool of fuel in your bilge, then running the blower isn't going to fix that.. or make any real impact?

I know this is one of those things, and real easy to say "just do it to be safe".. yea yea... I get that, I'm just trying to figure out what is really going on, and what happens when we run the blower.

I see no reason to run the blower after towing the boat to the lake - everything should be more than sufficiently blown out. I could see if the boat has been sitting for a long while, and some vabors have accumulated.. but if run, or towed recently.. should be pretty blown out. no?

It's about minimising the risk. In the circumstances you describe, the liklihood of vapour in the bilge is reduced, but not impossible. Even in the event of having run the boat you'd have to assume nothing in the fuel system has failed in the interim. The fuel vapour is heavier than the air and can gather in pockets in the right mixture. All you need is an ignition source and with an inboard there are many. Never assume that nothing can/should go wrong and that's what happened to me. For the time being the bilge blower is the best solution as it draws air from the point where fuel vapour is most likely to accumulate and removes it from the bilge.

[fijidaniel]

Ever since I read this thread, I run it every time I put the boat in the water. I don't run it any other time though. I tow my boat a few miles at 55 mph, so that probably minimizes the risk more than anything.

[Faceplant409]

Here's a picture of Jill's (Skibabe) "play station" after an incident... (originally posted on MBO) Not sure if this was a blower related thing, but a fire none the less...

[Baddog]

Here's a picture of Jill's (Skibabe) "play station" after an incident... (originally posted on MBO) Not sure if this was a blower related thing, but a fire none the less...

Bummer. Um, good looking engine??

[geogilbert]

When i was about 15 I was behind a 28 Bertram. The guy filled went to crank the boat and blew the engine cover about 30 feet in the air. I remember his wife standing on the dock about to step on the boat and the look on her face. She was about 4 steps from dead.

Ya I run my blower, and most of the time I find it still on when I hit the "All Off" switch. Leave it on if you burn it out it is a cheep replacement.

[MalibuTime]

I've been told that gas fumes are heavier than air and therefore SINK through the air. Thus opening your back hatches isn't going to do anything but allow the air/fuel vapor mixture reach the magic percentages for boom boom. Maybe someone can clarify that for me but the blower is there to suck out the fumes from the bottom of the compartments.

Yes, I believe they are heavier, yes, the tube should blow/suck then from the lower part of the engine compartment. I still believe that if you do a sniff test, heavier than air or not, if there is enought fume build up to worry about you will be catching a wiff of it during a sniff test. I always sniff test first start of the day regardless of where, when and what I was doing right before that. Basically, if the sniff test passes, I am good to go, but the blower will be on at all times anyhow unless we are up to speed.

For those that don't run your blower between stops, how are you going to know when you spring a gas leak to make sure you don't then turn over the ignition? (this is kind of like the tie down thread, don't need 'em until you really need 'em)

[jetskipro550]

I always run the blower for about 30 seconds before starting the boat and usually open the engine compartment too. If we are idling or just putting around we leave it on. Sometimes it runs all day as we forget that it's going. If it goes out it's cheap AND easy to replace.

[Baddog]

Lately I have been smelling a bit of gas when I remove the cover. i run the blower and haven't blown it up yet, but . . . . what are all the sources of a random gas smell when there are no visible leaks anywhere?

[jetskipro550]

Lately I have been smelling a bit of gas when I remove the cover. i run the blower and haven't blown it up yet, but . . . . what are all the sources of a random gas smell when there are no visible leaks anywhere?

Usually around here, the source is Mexican food

[Baddog]

Lately I have been smelling a bit of gas when I remove the cover. i run the blower and haven't blown it up yet, but . . . . what are all the sources of a random gas smell when there are no visible leaks anywhere?

Usually around here, the source is Mexican food

Apparently you haven't been eating much chinese JSP. That'll do it too.

[smeagol]

I struggle with this notion of having to turn on my blower in case I've developed a fuel leak. If I've developed a fuel leak, the blower doesn't fix that problem and I'm going to have to be 100% accurate in remembering to turn on the blower in time to clear the vapors until I independently find and fix the leak.

I know that boat engines are enclosed, and that makes them susceptible to vapor build-up, but are they at any more risk (or maybe even less risk) for developing a fuel leak than a car?

I'm not suggesting that the "better safe than sorry" approach should be ignored in this case (clearly - since I have no idea what I'm talking about), but I'm wondering if this is a real risk, or if it is just a perceived risk. Pictures of blown-up boats don't confirm the risk, they just build the perceived risk. I'd like to see data, or even an anecdote where someone in a newer boat says "I always hit my blower, but I forgot this one time, and boom".

It seems that if fuel leaks/vapors are a real substantial risk, then there should be a "vapor sensor" in the engine compartment that alarms to tell us to fix the problem. If fuel vapors are are a real risk, why do boat builders not install a sensor like this? They have them on hot water heaters.

[MalibuTime]

I struggle with this notion of having to turn on my blower in case I've developed a fuel leak. If I've developed a fuel leak, the blower doesn't fix that problem and I'm going to have to be 100% accurate in remembering to turn on the blower in time to clear the vapors until I independently find and fix the leak.

I know that boat engines are enclosed, and that makes them susceptible to vapor build-up, but are they at any more risk (or maybe even less risk) for developing a fuel leak than a car?

I'm not suggesting that the "better safe than sorry" approach should be ignored in this case (clearly - since I have no idea what I'm talking about), but I'm wondering if this is a real risk, or if it is just a perceived risk. Pictures of blown-up boats don't confirm the risk, they just build the perceived risk. I'd like to see data, or even an anecdote where someone in a newer boat says "I always hit my blower, but I forgot this one time, and boom".

It seems that if fuel leaks/vapors are a real substantial risk, then there should be a "vapor sensor" in the engine compartment that alarms to tell us to fix the problem. If fuel vapors are are a real risk, why do boat builders not install a sensor like this? They have them on hot water heaters.

The blower isn't in case you've developed a leak, it is for the case where you have not detected there is a leak, so I don't quite get your statement?

That is a dang good question, for the same reason RV makers put carbon dioxide detectors inside the RV, enclosed engines you would think would get vapor detection.

[JeffS]

Gasoline vapor detectors ARE installed on many, many boats. The question then I guess - why not Malibu?

Back when carbs were the norm, this was a much more significant issue. Don't get me wrong - it's not NOT an issue now...but when carbs were on all boats, there was a bowl full of fuel inside the engine compartment that was ready to evaporate as it sat.

Now, with EFI being the norm, it's a leak that is the primary culprit I guess.

I can't understand why anyone would NOT run the blower. Regardless how well written or established the argument (why should I have to, shouldn't boat makers do more, I don't believe it, whatever...) - the penalty for having vapor in the bilge and spark in the engine is boom. I never, ever want boom, so I always run the blower. More than that, I almost always lift the engine hatch and stick my nose down there at the beginning of the day.

A Fireboy vapor detection system is less than $200 if I remember right. I can't imagine why they are not standard equipment. But they're not. So I either buy one, or sniff and run the blower. Super-simple, one-button, not-a-big-deal, protects-my-family, zero-effort activity at the beginning of the day.

[smeagol]

I struggle with this notion of having to turn on my blower in case I've developed a fuel leak. If I've developed a fuel leak, the blower doesn't fix that problem and I'm going to have to be 100% accurate in remembering to turn on the blower in time to clear the vapors until I independently find and fix the leak.

I know that boat engines are enclosed, and that makes them susceptible to vapor build-up, but are they at any more risk (or maybe even less risk) for developing a fuel leak than a car?

I'm not suggesting that the "better safe than sorry" approach should be ignored in this case (clearly - since I have no idea what I'm talking about), but I'm wondering if this is a real risk, or if it is just a perceived risk. Pictures of blown-up boats don't confirm the risk, they just build the perceived risk. I'd like to see data, or even an anecdote where someone in a newer boat says "I always hit my blower, but I forgot this one time, and boom".

It seems that if fuel leaks/vapors are a real substantial risk, then there should be a "vapor sensor" in the engine compartment that alarms to tell us to fix the problem. If fuel vapors are are a real risk, why do boat builders not install a sensor like this? They have them on hot water heaters.

The blower isn't in case you've developed a leak, it is for the case where you have not detected there is a leak, so I don't quite get your statement?

That is a dang good question, for the same reason RV makers put carbon dioxide detectors inside the RV, enclosed engines you would think would get vapor detection.

Yeah, I didn't word that too well. If you have vapors, you have a leak, right. So, my point is that if you have a leak, you have an underlying problem that needs to be fixed. Running the blower obviously doesn't fix the underlying problem.

Jeff, to your question re: why doesn't everyone go through these steps... why don't you raise the lid and stick your nose down there every time you start the engine instead of just every morning. Is there not a risk that you get a leak/vapors during the course of the day? Or is it just that you have decided that there is not enough of a risk to check each time?

[REW]

Lately I have been smelling a bit of gas when I remove the cover. i run the blower and haven't blown it up yet, but . . . . what are all the sources of a random gas smell when there are no visible leaks anywhere?

Usually around here, the source is Mexican food

That and/or the vent

Works for the boat too

REW

[JeffS]

Jeff, to your question re: why doesn't everyone go through these steps... why don't you raise the lid and stick your nose down there every time you start the engine instead of just every morning. Is there not a risk that you get a leak/vapors during the course of the day? Or is it just that you have decided that there is not enough of a risk to check each time?

When running the boat, there's constant airflow through the engine compartment. Fumes won't have a chance to accumulate when the boat is being used due to ventilation and exchange of combustion air into the doghouse. If I sit at a sandbar for several hours, I do run the blower again. But every time...no...because of the constant airflow. I'm no expert, and I don't do more than average I don't think. But I have been around boats a really long time, and have seen a boat that blew up because of fumes (it was a municipal boat too...uff...awkward and embarrassing for that patrol).

[EZSnow]

Opening the motor box does not provide an added effect to the blower, it diminishes the effect of the blower. the blower draws air out of the bilge, creating an area of negative pressure that is (primarily) replaced by fresh air that is drawn through the front vents. When the motor box is opened, the flow of air through the bilge is broken and the effect of the blower exchanging the air in the bottom of the bilge is lost.

Pop the box to sniff it? Sure, not a bad idea. Leave it open to "help the blower"? Might as well just turn the key.

[smeagol]

It seems that if fuel leaks/vapors are a real substantial risk, then there should be a "vapor sensor" in the engine compartment that alarms to tell us to fix the problem. If fuel vapors are are a real risk, why do boat builders not install a sensor like this? They have them on hot water heaters.

Sorry for quoting myself... I'd like to hear thoughts regarding whether or not exploding engines are a real risk that running the blower eliminates, or an old risk that we have made part of our habits? If they are a real risk, are there any ski boat manufacturers installing sensors?

[REW]

It seems that if fuel leaks/vapors are a real substantial risk, then there should be a "vapor sensor" in the engine compartment that alarms to tell us to fix the problem. If fuel vapors are are a real risk, why do boat builders not install a sensor like this? They have them on hot water heaters.

Sorry for quoting myself... I'd like to hear thoughts regarding whether or not exploding engines are a real risk that running the blower eliminates, or an old risk that we have made part of our habits? If they are a real risk, are there any ski boat manufacturers installing sensors?

Sensros.........What a concept, we have moniters for our ballest (newer boats) why not in the engine compartment?