Bilge blowers not required on jet skies?

[rekit]

Anyone know why bilge blowers are not required on jet skis? All inboard and I/O boats have 'em, even if they are fuel injected. I went to charge my two Honda's today. They are stored out in the shade. When I removed the seats to get to the batteries, the gas fumes were strong. Hell, on a boat you may be a little ways from the explosion instead of straddling it like we do! On my Mercruiser you run the blower for 4-5 minutes before you start it.

I posted this in the jet ski forum, but might get the answer here.

 

[sw33ttooth]

Re: Bilge blowers not required on jet skies?

not 100% sure never been on a jet skii and i have no notion of starting any time soon. however it must be due to how the air intake is put togather. the main reason why blowers are required on i/o's is the fact that the engine gets all its air from the bilge and if it backfires, like they often do when the carb is mis-adjusted, it could blow up.

thats all the input i can give ya.

 

[raven7]

Re: Bilge blowers not required on jet skies?

I always removed my seats before unhooking the tie down straps and getting ready to launch. Gives it time to air out prior to starting the engine.

 

[relocyo]

Re: Bilge blowers not required on jet skies?

Well to be a grouch, I guess ill let you know that posting multiple threads about the same thing tends to anger the powers that be, just a heads up... Although smallboatlover got away with it time and time again.... Lol

Just a little humor, I mean nothing by it.... Just trying to help :redface:

 

[ziggy]

Re: Bilge blowers not required on jet skies?

I always removed my seats before unhooking the tie down straps and getting ready to launch. Gives it time to air out prior to starting the engine.

i've had two jet skis. well, one jet ski, one waverunner. both had the same statment in there owners manuals. remove seat and let it air out prior to starting. why this is 'good enough', i don't know. but that was the sop for pre start on the ones i had.

 

[mr.jones]

Re: Bilge blowers not required on jet skies?

I am by no stretch of the imagination an expert, but if I had to venture a guess I would say that the difference is in ease of access and size of area to be vented. With a jet ski it is still expected that you air out the bilge, but because the seat is so easily removed and the engine compartment fairly small (airs out quickly) they likely bypassed the extra weight and space needed for a blower. In the case of a full sized I/O the engine compartment is much larger and thus a little extra help is needed to force the fumes out of the bilge/engine compartment. Just my guess, I could be dead wrong.

 

[zagger]

Re: Bilge blowers not required on jet skies?

Not sure about the new models but all older models had a venting cap that vented to the outside so theoretically there should be no fumes inside the hull.

 

[sasto]

Re: Bilge blowers not required on jet skies?

External fuel tank!?

 

[Fireman431]

Re: Bilge blowers not required on jet skies?

Fuel tanks are contained within the hulls and the skis get their air from an airbox mounted on the carbs (or FI), same as every other engine. Most have some sort of fresh air induction, but that is really only (truly) useful when under way. In lieu of a blower, the manuals tell you to remove the seat as part of the pre-ride checklist which gives you the opportunity to visually examine the engine, pump, shaft, etc as well as ventilate the engine compartment. In my personal opinion, they should have blowers as well as bilge pumps.

 

[H20Rat]

Re: Bilge blowers not required on jet skies?

Not sure about the new models but all older models had a venting cap that vented to the outside so theoretically there should be no fumes inside the hull.

Gas fumes sink...

They are coast guard exempt from that regulation, otherwise they fit the bill for needing ventilation. The reason they don't is that there isn't the risk that a big I/O has. There is no alternator, and the ignition and starter are better protected/sealed than a typical I/O. Worst case, there isn't nearly as much volume, and a spark/explosion will usually just pop the seat off without actually hurting anything. (yes, I've seen it first hand)

 

[DBreskin]

Re: Bilge blowers not required on jet skies?

Just guessing, But perhaps jet skis don't have a blower because the hull is sealed to prevent them from sinking. If there was a vent hole for blower exhaust, water could get in during operation and sink the ski.

 

[Brewman61]

Re: Bilge blowers not required on jet skies?

I hear occasionally about an I/O or inboard blowing up. Never hear anything like that about PWC's. You can bet the personal injury vultures (aka lawyers) would be all over this if it was a problem. Whatever they have seems to work.

 

['78 Crusader]

Re: Bilge blowers not required on jet skies?

Solution = sell the jetskis and buy a real boat with a blower.

Glad I could help.

 

[25thmustang]

Re: Bilge blowers not required on jet skies?

Not sure, as I personally have been using both a carbed and a FI ski this summer and never thought about a bilge blower. Never smelled any gas fumes though until shes running.

Maybe has something to so with the mixed fuel/oil? Mine are both two strokes, would a 2 stroke be any less prone to an explosion?

 

[slag]

Re: Bilge blowers not required on jet skies?

Just guessing, But perhaps jet skis don't have a blower because the hull is sealed to prevent them from sinking. If there was a vent hole for blower exhaust, water could get in during operation and sink the ski.

No jetski has a sealed hull to prevent them from sinking. They all have to get fresh air from somewhere.

 

[slag]

Re: Bilge blowers not required on jet skies?

Read the owner's manual of your jetski and just use common sense. You should always perform a pre-ride check at any rate which includes a visual inspection of the bilge. I typically remove the seat from the jetski when I get to the lake (park in a parking spot because I still have to remove the transom straps, put in the plugs if so equipped, check to make sure they will start out of the water (safe to do with a jetski for short periods of time), get the lanyards out, grab the lifevests, etc. By that time, the hull has had time for fresh air to get in. Put the seat back on, put it in the water, and go.

I was at Clinton lake a few years ago when a jetski did blow up due to gas being put in the air intake instead of fuel fill area. The seat blew off as did the rider and he only had scrapes and cuts, no broken bones. My X2 had removable body panels that would blow off if there was a small explosion as well.

 

[H20Rat]

Re: Bilge blowers not required on jet skies?

No jetski has a sealed hull to prevent them from sinking. They all have to get fresh air from somewhere.

On most seadoos', at least the 2 strokes, the air intake is part of the seat. The actual inlet is right by the drivers knees, and it then travels through the length of the seat to a splash tube that dumps directly above the bilge pump/drive shaft. (since that area is going to be wet from the carbon seal, and has the bilge pump right there, its the best location to dry out the air coming in)

yep, far from sealed. Its just really good ad separating out water and air before it makes it to the engine.

 

[H20Rat]

Re: Bilge blowers not required on jet skies?

Not sure, as I personally have been using both a carbed and a FI ski this summer and never thought about a bilge blower. Never smelled any gas fumes though until shes running.

Maybe has something to so with the mixed fuel/oil? Mine are both two strokes, would a 2 stroke be any less prone to an explosion?

Most 2 stroke pwc's aren't premix. They are injected 2 stroke, so you have a gas tank and an oil tank.

 

[haulnazz15]

Re: Bilge blowers not required on jet skies?

Most jet ski air intakes are located right behind the forward storage compartment. The one thing I will say is that even on carbed models, the actual air manifold is a great flame arrestor because it is normally a large inverted chamber. The chamber serves the purpose of flame arrestor AND as a protection against water instrusion when the jet ski rolls over after a fall. You'd be a lot harder pressed to get a backfire to come out of the jetski intake than you would the simple baffle on a normal I/O. You should vent the engine compartment after having sat a while, though.

 

[robert graham]

Re: Bilge blowers not required on jet skies?

They're waiting for some senator or congressman's son or daughter to get blown up on their jet ski, then we'll see legislation requiring bilge blowers!