One side of the diaphram on the fuel pump is exposed to fuel and the other side to atmosphere. This allows a pressure differential to develop as the dia phragm oscillates and results in fuel movement or pumping. Without the vent, the pressure differential would be much lower (due to the added resistance) and the pump would be less effective. The vent is located on the top side of the diphragm housing, which is the wide round part of the fuel pump assembly. On my unit there was a slotted, threaded, aluminum plug with a hole drilled in the middle. This made it easy to pull the plug and put a hose fitting there instead. Drill and tap the carb to add a similar fitting near the top of the carb and connect the two with fuel line tubing. When the diaphragm eventually ruptures and leaks fuel onto the vent side, the fuel will dump harmlessly into the carb instead of the bildge (obviously the boat won't run too well with a failed fuel pump so dumping the excess fuel into the carb doesn't hurt). I sent some pics the list previously; will try to forward to you separately.
----- Original Message -----
From: "jd" <jdood@...>
To: "Evinrude & Johnson Boats of the 1960's and 70's" <omc-boats@...mate.com>
Sent: Sunday, November 1, 2009 10:56:45 PM GMT -05:00 US/Canada Eastern
Subject: Re: [OMC-Boats] engine wierdness
what is it, where is it, and how do i do it?
On Nov 1, 2009, at 7:04 PM, ANDY PERAKES wrote:
> Good news to hear its working. If you haven't already plumbed the
> vent on your fuel pump to the carb, I highly recommend you do so.
> Without it, the pump dumps fuel right into the bildge if the
> diaphram ruptures. Unfortunately I know this from experience, but
> we were very, very lucky no one got hurt and the boat suffered only
> minor damage. Please, everyone, don't take the risk.
>
>
> ----- Original Message -----
> From: "jd" <jdood@...>
> To: "Evinrude & Johnson Boats of the 1960's and 70's" <omc-boats@...timate.com
> >
> Sent: Sunday, November 1, 2009 1:39:34 PM GMT -05:00 US/Canada Eastern
> Subject: Re: [OMC-Boats] engine wierdness
>
> nope, got the stock mechanical FP that's bolted on the side of the
> engine. which seems to be having no probs since it squirted fuel
> with the same force and my bilge pump when i disconnected and tested
> it.
>
>
>
> On Oct 31, 2009, at 9:16 PM, ANDY PERAKES wrote:
>
> > Do you have an electric or mechanical fuel pump? What you describes
> > sounds like an electric. If so, disconnect the fuel line ahead of
> > the fuel/water separator and pump some into a glass jar. Do it a
> > couple of times and it will be obvious if you have any water in the
> > tank. Doesn't comepletely eliminate the possiblility, but knocks
> > once more thing off the list. The fact you have a fue/water
> > separator makes it even more unlikely this is your problem, but its
> > still possible. My system runs from the tank to the fuel/water
> > separator/filter to the mechanical pump mounted on the lower port
> > side to the carb. I replaced my pump a few years ago, but I kept
> > the glass bowl and "bundt cake" filter since it provides a
> > convenient sight glass into the fuel system.
> >
> >
> > ----- Original Message -----
> > From: "jd" <jdood@...>
> > To: "Evinrude & Johnson Boats of the 1960's and 70's" <omc-boats@...ultimate.com
> > >
> > Sent: Saturday, October 31, 2009 4:02:41 PM GMT -05:00 US/Canada
> > Eastern
> > Subject: Re: [OMC-Boats] engine wierdness
> >
> > from my tank the fuel goes to a clear plastic inline filter thing,
> > then a couple feet on to the fuel water separator, then to the
> > carb. the blob of water sorta makes sense. so i guess it the
> water
> > blob would mix with the air vapor and a mixture of ONLY air and
> water
> > (zero gas) would shoot equally into all 6 cylinders and potentially
> > kill the whole engine instantly. still seems like it would have
> > to be a big blob of water - like maybe a teaspoon or something -
> to do
> > that though. but like you say, anything is possible.
> >
> >
> >
> >
> > On Oct 30, 2009, at 3:28 PM, ANDY PERAKES wrote:
> >
> > > Water in fuel is kinda like an oil & vinegar salad dressing -- you
> > > can shake it all you want, but it doesn't mix well and it doesn't
> > > stay mixed for long. It is possible to get a sudden "blob" of
> water
> > > that can suddenly kill the engine and that could be why it takes
> > > awhile to restart. It wouldn't be the first suspect on my list
> > > either, but anything is possible! Do you have the glass bowl on
> > > your fuel pump? That'd be one easy check you can make, but as
> > > stressed by others, meticulous attention to detail is the only way
> > > to nail down a problem like this.
> > >
> > >
> > > ----- Original Message -----
> > > From: "jd" <jdood@...>
> > > To: "Evinrude & Johnson Boats of the 1960's and 70's" <omc-boats@...s.ultimate.com
> > > >
> > > Sent: Friday, October 30, 2009 1:41:15 PM GMT -05:00 US/Canada
> > Eastern
> > > Subject: Re: [OMC-Boats] engine wierdness
> > >
> > >
> > > On Oct 29, 2009, at 5:48 PM, ANDY PERAKES wrote:
> > >
> > > > I once had a crack in the rotor that would cause it to lose
> > contact
> > > > at different speed ranges so it can be almost anything.
> Sometimes
> > > > failures can be induced by vibration, sometimes by heat,
> sometimes
> > > > both or something completely different. As metal things like
> > coils
> > > > and wires expand and contract as they heat and cool, it can
> cause
> > > > them to make intermittent contact that can be maddening to
> > > > diagnose. Fuel could very well be a possibility too, things
> would
> > > > indeed stop quick if you suddenly injected an air/water mix
> > instead
> > > > of an air/fuel mix.
> > >
> > > ok so this is something i've wondered about........still learning
> > how
> > > engines actually work i guess..........if you have some water in
> > your
> > > line somehow and it makes it's way to the carb bowl, isn't it
> going
> > > to get diluted a bit by the fuel already in the bowl? And once
> past
> > > that point, wouldn't it go into one of the 6 cylinders OR if
> all 6
> > > equally, isn't it further dilluted at that point being spread out
> > > among 6 places? And if that's all true, then it seems the
> engine
> > > would just cough a bit, then pick right back up a second later
> when
> > > it got fed clean gas again? Seems like it would take a lot of
> > > water in the line to completely and suddenly kill the engine, but
> > im
> > > not sure how it all works.
> > >
> > >
> > >
> > > > Best way to check that would probably be connecting to a remote
> > > > tank, but remember you'll still need to purge everything in the
> > > > lines and bowl. It helps a lot that it starts back up for you.
> > > > Good luck!
> > >
> > > yeah, i'm glad about that too. although, it does take a while
> > to
> > > get it started again. not the greatest feeling when you are
> > out on
> > > the columbia alone in 50 degree weather and there aren't any other
> > > boats around.
> > > >
> > > >
> > > > ----- Original Message -----
> > > > From: "Scott Veazie" <scottveazie@...>
> > > > To: omc-boats@...
> > > > Sent: Thursday, October 29, 2009 4:05:40 PM GMT -05:00 US/Canada
> > > > Eastern
> > > > Subject: Re: [OMC-Boats] engine wierdness
> > > >
> > > > Yup...no spark for the plugs. Also don't discount a bad
> > condenser,
> > > > I had one leave me stranded.
> > > >
> > > > > From: jdood@...
> > > > > To: omc-boats@...
> > > > > Date: Thu, 29 Oct 2009 12:45:06 -0700
> > > > > Subject: Re: [OMC-Boats] engine wierdness
> > > > >
> > > > > yeah, maybe the coil - hope its something that easy. i guess
> > that
> > > > > would do it wouldn't it? if i understand it all correctly, if
> > the
> > > > > coil shuts down then no spark is being send to ANY of the
> plugs,
> > > > > right? which would make the engine completely die instantly.
> > > > >
> > > > >
> > > > > On Oct 29, 2009, at 10:41 AM, Scott Veazie wrote:
> > > > >
> > > > > > JD-
> > > > > >
> > > > > > >From my past experience, I would start with a new coil,
> then
> > > get
> > > > > > new points, condenser, cap, rotor, check all spark plugs and
> > > > wires.
> > > > > > Get all that ignition nonsense eliminated as a potential
> > > problem,
> > > > > > and then go from there. You probably won't have to replace
> > your
> > > > > > dist. cap though.
> > > > > >
> > > > > > ~Scott
> > > > > >
> > > > > > > From: jdood@...
> > > > > > > To: omc-boats@...
> > > > > > > Date: Thu, 29 Oct 2009 10:00:31 -0700
> > > > > > > Subject: Re: [OMC-Boats] engine wierdness
> > > > > > >
> > > > > > >
> > > > > > > i just don't see how it can be any kind of electrical
> system
> > > > thing,
> > > > > > > esp since i re-did most of the wiring this summer and it's
> > now
> > > > very
> > > > > > > solid. but who knows. and what "electrical" stuff is
> > happening
> > > > > > > with the engine while its running anyway?
> > > > > > >
> > > > > > > - one wire sends power to the starter when the key is
> > turned -
> > > > > > that is
> > > > > > > working fine
> > > > > > >
> > > > > > > - there's a purple wire that runs to the electric choke (i
> > > > guess) on
> > > > > > > the carb - perhaps that?
> > > > > > >
> > > > > > > - there's theres a wire going to the coil and stuff -
> > perhaps
> > > > that?
> > > > > > >
> > > > > > > - then there's the alternator - perhaps that?
> > > > > > >
> > > > > > >
> > > > > > > The last 3 on this list i don't really understand at all,
> > esp
> > > > what
> > > > > > > their function is AFTER the engine is up and running. If
> > > > > > > electrical, it has to be something that functions not just
> > to
> > > > start
> > > > > > > the engine, but to keep the engine running. Doesn't that
> > just
> > > > > > > narrow it down to the alternator? Or is there other
> > electrical
> > > > stuff
> > > > > > > that has to do with the engine staying running?
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > On Oct 29, 2009, at 9:02 AM, ANDY PERAKES wrote:
> > > > > > >
> > > > > > > > I tend to agree with the electrical suspect. Fuel/air
> > > problems
> > > > > > > > generally linger a bit and don't result in an immediate
> > > drop-
> > > > out
> > > > > > > > like you describe. Anything is possible though. I like
> the
> > > > > > > > guidance Lee sent out awhile back where he said to
> > > > eleiminate the
> > > > > > > > possibility of electrical problems first since that's
> > > usually
> > > > > > > > quicker and easier to do. Trouble is, intermittent
> > > electrical
> > > > > > > > problems can be a nightmare to trace. Is there any
> > > > possibility of
> > > > > > > > hooking up some basic instrumentation to see if there is
> > any
> > > > > > > > electrical effect when it happens? If you see a sudden
> > > voltage
> > > > > > > > change or current drop out, that would be a clear
> > indicator.
> > > > Good
> > > > > > > > luck!
> > > > > > > >
> > > > > > > > Andy
> > > > > > > > '67 Reveler
> > > > > > > >
> > > > > > > >
> > > > > > > > ----- Original Message -----
> > > > > > > > From: "jd" <jdood@...>
> > > > > > > > To: "Evinrude & Johnson Boats of the 1960's and 70's" <omc-boats@...
> > > > > > > > >
> > > > > > > > Sent: Thursday, October 29, 2009 11:44:16 AM GMT -05:00
> > US/
> > > > Canada
> > > > > > > > Eastern
> > > > > > > > Subject: [OMC-Boats] engine wierdness
> > > > > > > >
> > > > > > > > took my boat out for the last of possible testing this
> > > season
> > > > > > before
> > > > > > > > things get too cold and rainy. didn't go as i hoped.
> i'll
> > > > > > > > try and condense this down to it's simplest form:
> > > > > > > >
> > > > > > > > BEFORE (about a month ago):
> > > > > > > >
> > > > > > > > except for some slightly fast idling, engine ran well.
> > > Then I
> > > > > > > > noticed it starting to do this weird intermittent thing
> > > where
> > > > > > all the
> > > > > > > > power (throttle) would just drop down to zero. It seemed
> > to
> > > > happen
> > > > > > > > mainly during acceleration up to plane. This all was
> > > > happening at
> > > > > > > > the end of the season, so I have pretty much had the
> boat
> > > > > > sitting for
> > > > > > > > the past month waiting for parts and time. But I was
> > > > thinking it
> > > > > > was
> > > > > > > > related to my falling apart carb and / or and electrical
> > > thing
> > > > > > > > related to my rebuilt shifter switch. so......
> > > > > > > >
> > > > > > > > AFTER (yesterday):
> > > > > > > >
> > > > > > > > - I installed my nice practically new carb (rebuilt by
> > > flying
> > > > > > fish).
> > > > > > > > keep in mind, it was the exact same carb i have always
> had
> > > > on the
> > > > > > > > boat, just completely rebuilt. I also changed my air
> water
> > > > > > separator
> > > > > > > > cartridge beforehand to avoid any chance of issues from
> > fuel
> > > > > > that had
> > > > > > > > sat for a month.
> > > > > > > >
> > > > > > > > - I installed a NOS shifter switch that I recently
> > acquired.
> > > > > > Tested
> > > > > > > > with light after install, everything checked out. And
> as I
> > > > said,
> > > > > > > > it's basically new.
> > > > > > > >
> > > > > > > >
> > > > > > > > So after those two major upgrades, the engine is doing
> the
> > > > same
> > > > > > dang
> > > > > > > > thing. Started up, let it warm up a bit, took it for a
> > spin.
> > > > > > > > About 5-10 seconds after getting up on that first plane
> > > > everything
> > > > > > > > just dropped down to zero and unlike the past times,
> this
> > > > time the
> > > > > > > > engine died at the same time. Had to crank it over
> several
> > > > times
> > > > > > > > for it to start back up, and when it did, with the red
> > lever
> > > > set
> > > > > > at
> > > > > > > > full throttle it took several seconds for the RPMS to
> > climb
> > > > up to
> > > > > > > > where they should be. I limped back to the dock.
> > > > > > > >
> > > > > > > > Then while at the dock idling for a few minutes, all of
> > the
> > > > sudden
> > > > > > > > it just died again. At idle this time, not while
> > > accelerating.
> > > > > > > > And every time it dies it is quick. It's not like it
> sits
> > > > there
> > > > > > and
> > > > > > > > slowly dies. It just cuts out suddenly. So I of course
> > tried
> > > > to
> > > > > > > > restart it. Nothing for several tries, then it acted
> > like it
> > > > was
> > > > > > > > going to start, then it finally starts, coughing and
> > > > sputtering a
> > > > > > > > bit, then very slowly climbs up to full throttle (in
> > > neutral).
> > > > > > > > I started thinking maybe a fuel pump issue. Disconnected
> > > fuel
> > > > > > > > line, cranked engine, plenty of pumping of fuel
> happening.
> > > > > > > >
> > > > > > > > It seems sort of electrical in the way it just all of
> the
> > > > sudden
> > > > > > dies
> > > > > > > > either at idle or accelerating. Yet when it finally
> starts
> > > > back
> > > > > > up it
> > > > > > > > coughs and sputters and smokes a bit. Which sounds like
> > bad
> > > > fuel,
> > > > > > > > yet I have a new water/fuel separator cartridge, the
> > carb is
> > > > new,
> > > > > > > > and nothing looks dirty with the inline regular fuel
> > filter.
> > > > > > > >
> > > > > > > >
> > > > > > > > Any ideas?
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > >
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Received on Monday, 2 November 2009
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