I agree that the chances of there being an explosion are low. I have smelled gas in the cabin before I made the modification on my boat. Gave me a headache which was why I went after the source. In the end, all it takes is just the right amount of fumes and a spark for the big boom to happen. I sleep better knowing my aft locker is safe ( better stated 'safer' as there are no guarantees). :: Dave Scobie jerry montgomery <jerry@jerrymontgomery.org> wrote:
I'll agree with Tom here- unless you stood the boat on it's head the only gas that could get in the cabin area would be fumes, and I think they would be so diluted that they wouldn't be a problem.
jerry ----- Original Message ----- From: "Tom Smith" <openboatt@gmail.com> To: "For and about Montgomery Sailboats" <montgomery_boats@mailman.xmission.com> Sent: Monday, January 13, 2014 6:51 PM Subject: Re: M_Boats: outboard motors
Yup, you're right Dave, there's a gap there--along the aft side of the top of the locker. Yet that locker was obviously specifically designed to house an outboard motor fuel tank, so go figure.
Because my locker is probably 12 inches deep with what appears to be very good ventilation, and because gasoline fumes are much heavier than air, I remain convinced that gasoline fumes from a marine grade fuel tank in good working order pose no hazard (at least on my boat--if you sail with me, you're rolling the dice fireball-wise). I'll go out on a limb here, but I suspect you're running a far greater fire risk when you pull in to fuel up your car than by keeping an OB fuel tank in the aft locker.
I would be interested to hear from an M sailor (or their caregiver) who has had an explosive experience.
Thanks for the heads-up on the gap though. That may come in handy when I lose the standard motor mount... t
t _/\_
On Mon, Jan 13, 2014 at 5:14 PM, W David Scobie <wdscobie@yahoo.com> wrote:
Tom:
just to confirm -
when looking into the locker, without looking up, the locker does seem to be 'sealed'. it is the 'upper/top' locations outlined below that are the concern.
be sure to feel along the top of the aft end of the locker. this is likely open to the space between the aft cockpit wall and the transom. if this gap isn't filled gas can get into the cabin.
also look along the aft-top of the locker port and starboard. the locker walls, or the 'pan that makes up the locker' are not likely full height, are not taped/glassed to the 'top' of the aft locker, and open to the aft ends of the port and starboard lockers. i was able to reach over this partial wall and unbolt my M17's motor mount.
there is also a gap between the locker's wall and curved space where the locker lid sets. this area is very small, but not sealed. i filled this area with thickened epoxy and then covered with mat & glass.
see pictures -
http://m17-375.webs.com/apps/blog/show/prev?from_id=6848827
(look at photos following the heading 'Pictures of the completed fiberglass work:' (about 1/2 through the post).
i believe i have more pictures of the project that show the locations i sealed.
again, the bottom of the locker is sealed (it must be or when water enters the locker the water drains into the cabin). the _top_ of the locker isn't sealed.
this isn't to say your boat's locker isn't sealed .. but the Jerry's SOP didn't include making the aft locker 'gas tight' to the cabin.
:: Dave Scobie
-------------------------------------------- On Mon, 1/13/14, Tom Smith <openboatt@gmail.com> wrote:
I had to walk out to my shop to look at my M17 after reading your caution, Dave, because I was nearly positive there is no vapor access from the aft locker to the interior of the boat. There is not, plus there are two large access holes from the locker through the transom--probably 2"-- either side of the rudder, so there's pretty good circulation. I can't speak for other late model jerry-built boats, nor can I speak for those Bob is building.
So at least for my '92 M17, I have no qualms about keeping an outboard fuel supply there, though I'd certainly hesitate to store propane anywhere.
Regarding OB info, Thomas, search the msog archives--I'd bet there are hundreds, perhaps thousands, of posts on motors there. t
t _/\_
On Mon, Jan 13, 2014 at 3:56 PM, W David Scobie <wdscobie@yahoo.com> wrote:
i view gasoline to be as dangerous as propane (or any heavier than air gas/fuel).
remember folks - a stock 1983 or newer M17's aft locker has no vapor
barrier to the cabin ... don't store your fuel (gas, propane, butane, etc)
in the aft locker unless you modify the boat (i sealed off my M17's locker and installed proper airflow vents).
:: Dave Scobie
--------------------------------------------
On Mon, 1/13/14, Thomas Buzzi <thomaspbuzzi@gmail.com> wrote:
Following along, was interested to hear about the 3.5 on the Precision 18. I am leaning in that direction. Tohatsu's (being the first outboards ever produced) have a pretty good reputation for reliability. I have always been concerned about propane in a boat since it is heavier than air the fumes could find their way below and then with a little spark.......... This has been a
great string for information.
Thanks to all who have contributed. Tom B
On Mon, Jan 13, 2014 at 3:40 PM, W David Scobie <wdscobie@yahoo.com> wrote:
Tom (and others following along):
yeah, the issue is when the motor is cold she will not idle
... you need
to advance the throttle a good amount ... and she sputters and gasps, to keep her running until warmed up. barely wants to run if in gear.
for the pulls it seems that you need have the motor turning over a bunch
to get the gas to travel from bottle through the fuel lines. once motor has started she will fire up in one or two pulls after stopping IF you
don't unscrew the fuel bottle.
now ... the instructions for the motor say to unscrew the fuel bottle if
you are not going to use the motor again in a 'short period of time'. i
take this to meaning, as there is no fuel off valve, that they don't trust
the motor not to leak gas (you kill the motor like all other outboards with a
red button by the throttle lever). again, there is no
'fuel valve' so
when the
throttle is in idle some gas will leak? there is no
'off'
throttle position. is there an 'interconnect' that only allows the fuel to
feed if the motor is turning (either running or when being bulled)?
that 'unscrew the bottle' thing i don't like. this means that if you sail all day you shouldn't keep the bottle in place. if you need to get the
motor running quickly you must screw the bottle into place and pull many
times to get fuel to the cylinder. i can fill a Honda 2HP gasoline motor and start it faster than the prior described process. or, just hope the
motor doesn't leak gas all day and you don't find you are without fuel when
wanting to start the motor.
:: Dave Scobie
--------------------------------------------
On Mon, 1/13/14, Tom Jenkins <tjenk@gte.net> wrote:
Dave,
I don't know why a choke would be
necessary, as their purpose is to enrich the fuel mixture until the engine is warm enough to vaporize all the fuel
droplets. Propane is of course already a vapor at boating
temperatures (unless you are boating on Mars, which has some
other negatives).
As
for
the 12-15 pulls, that is equally puzzling from a physics
perspective. I wonder if other folks have this problem.
Glad you brought it up for discussion.
Tom
M17 Scintilla
On
Jan 13, 2014, at 10:06 AM, W David Scobie wrote:
i don't recommend a
the LEHR 2.5 is only available in a short shaft.
glad you like your
LEHR Steve. i'm not fully happy with the one Sage Marine purchased
short-shaft outboard on an M17 ... cavitation city! sadly, -
poor fit/finish, doesn't run correctly
(not running up to full RPM), difficult to start first time
(when cold or just after installing fuel bottle 12-15 pulls required), no choke (is needed for a cold start to keep motor running until warmed up), and no fuel cutoff.
:: Dave Scobie
--------------------------------------------
On Mon, 1/13/14, Steve Lindeman <lindeman.steven@gmail.com> wrote:
I
switched to the Lehr 2.5 propane
aux power for my M-15
last year. It
should have plenty
of power for the
M-17. I haven't used it much yet but
been happy so far. No hassle with winterizing or gas
spills. It only has F-N so it requires a 180 turn for
reverse. I was concerned about this but it hasn't been
a
problem.
Steve Lindeman
M-15 Sadie
Lee
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