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1. 09:16 PM - Re: Fuel Mixture (mike Pienaar)
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Subject: | Re: Fuel Mixture |
Thanks again for your help, got my engine started and will check oil level
in fuel pump again when I have run it again.
I cannot visualise what the oil does in the fuel pump. I have model 5151.03
and the manual mentions oil in through pressure reducing valve (29)
with the level controlled by a drain hole (31) and out to the scavenge
pump (32) You say "The pump is just sensing oil pressure"
May I ask you to explain again.
If it is not too much trouble is there a convenient time for us to chat on
the phone?
Thanks again and keep well
Mike
On Thu, Sep 10, 2020 at 1:19 PM sjbeaver <sjbeaver@gmail.com> wrote:
> The method to check ignition timing is pretty simple. Run the engine at
> maximum RPM and test each mag. You should see a drop of 25 RPM. If not,
> adjust the mags as necessary to get that. Advancing the timing will give
a
> smaller drop, retarding it a larger one (I think)
>
> There can be no "one-way valve" because no oil actually flows anywhere.
> The pump is just sensing oil pressure.
>
> Steve
> --
> Stephen Beaver
> Tel: 614-937 4189
>
>
> On Sep 7, 2020, at 6:00 PM, mike@vision499.com wrote:
>
> Thank you very much, I think it was flooded and then I took the spark
> plugs out and blew compressed air through the plug holes. When I tried
> again I might have been wary of flooding it again and did not prime enoug
h.
> Will try again to-morrow.
>
> Is there an easy way to check ignition timing?
>
> When I mentioned the "return oil line from the fuel pump" I was referring
> to the oil passages that I presume run through the mounting flange betwee
n
> the fuel pump and the cam shaft sump. One to supply oil and one to drain.
>
> Will let you know what happens to-morrow
>
> Thanks again
>
> Mike
>
> *From:* owner-lom-list-server@matronics.com <
> owner-lom-list-server@matronics.com> *On Behalf Of *sjbeaver
> *Sent:* September 7, 2020 12:39 PM
> *To:* lom-list@matronics.com
> *Subject:* Re: Lom-List: Fuel Mixture
>
> Mike,
>
> Those are interesting results! You appear to have the older style pump an
d
> you are correct that it should be serviced with engine oil up to the leve
l
> of the filler plugs.
>
> If there is a spark (at about the correct time) and the primer is
> delivering fuel then it is hard to understand why it didn't fire to some
> extent. Could it have been flooded? Inverted engines are rather prone to
> flooding. You can try clearing the engine out by propping it backwards, b
ut
> waiting for 20 minutes and trying again with the throttle about half way
> open is usually best.
>
> I am confused by your reference to the "return oil line from the fuel
> pump". There should be three connections to the pump: fuel inlet, fuel
> return and fuel pressure. Older pumps may also have a hose nipple on the
> side to vent the oil system. This is usually connected to small hose
> running upwards above the level of the and is open at the top.
>
> Steve
> --
> Stephen Beaver
> Tel: 614-937 4189
>
>
> On Sep 6, 2020, at 7:28 PM, mike@vision499.com wrote:
>
> Hello
>
> I have been away for a while but back now.
>
> I drained the sump on the Cam Cover and there was about a cup of oil.
>
> There is a large plug on the side of the fuel pump and I assumed that thi
s
> is the level the oil is supposed to be that is mentioned in the manual.
I
> filled the fuel pump to this level and it took about =C2=BC cup or +/- 60
ml
>
> When I tried to start the engine there is now nothing, not even a
=9Cpoof=9D
> or even one firing on the primer fuel. I tested for spark and that seems
> to be OK, and I can hear the Slickstart buzzing when I power it up
>
> I removed all the plugs and fuel injector nozzles, I fitted a nut to one
> of the nozzles and rotated the prop by hand, I got one squirt of gas out
of
> the nozzle but after that I only saw drops forming at the tip of the nozz
le.
>
> Is the return oil line that runs from the fuel pump to the sump equipped
> with a one way valve? I thought of running oil into the fuel pump and the
n
> checking if oil runs out of the sump plug cam case plug. Not sure if ther
e
> is a direct connection, but there must be something that stops the cam ca
se
> oil draining into the fuel pump.
>
> The deposits at the rear of the exhaust manifold is darkish gray
>
> Would appreciate you suggestions.
>
> Thanks
>
> Mike
>
> *From:* owner-lom-list-server@matronics.com <
> owner-lom-list-server@matronics.com> *On Behalf Of *sjbeaver
> *Sent:* August 24, 2020 5:08 AM
> *To:* lom-list@matronics.com
> *Subject:* Re: Lom-List: Fuel Mixture
>
> That is a surprising amount of oil. In a normally functioning, current
> revision engine I would expect to see perhaps a table spoon of oil. In th
e
> older style pump with a filler port on the side, perhaps a cup. Then agai
n
> I have never left the pump open overnight. There is a connection from the
> engine oil system to the pump in that one of the factors the pump uses to
> set the fuel mixture is oil pressure.
>
> I would suggest proceeding as follows:
>
> 1. Remove the drain plug/screen under the scavenge pump. How
> much oil do you see there? If you see a a cup or more then I would sugges
t
> all is well. If you see almost none then it would appear that the cam cas
e
> oil is somehow leaking into the injection pump. This seems unlikely thoug
h
>
> 2. Put everything back together and run the engine. Asses the
> performance per my previous email and then remove the oil drain plug in t
he
> pump again. How much oil this time? (Use something more scientific than t
he
> hangar floor to measure it :) )
>
> Steve
> --
> Stephen Beaver
> Tel: 614-937 4189
>
>
> On Aug 24, 2020, at 12:04 AM, <mike@vision499.com> <mike@vision499.com>
> wrote:
>
> Hello Steve
>
> I also thought it was impossible, I drained it from a small plug at the
> bottom of the fuel pump, the plug only needs a 12mm wrench so is small.
> Working forward from the rear of the pump there is a small slotted screw
> and then the plug. These are the only fittings on the bottom of the fuel
> pump. I can see a large nut on the camshaft cover that I assumed to be th
e
> drain under the scavenge pump, I did not open that. Could this oil have
> siphoned from somewhere?
>
> Thanks for you help
>
> Mike
>
>
> *From:* owner-lom-list-server@matronics.com <
> owner-lom-list-server@matronics.com> *On Behalf Of *sjbeaver
> *Sent:* August 23, 2020 7:57 PM
> *To:* lom-list@matronics.com
> *Subject:* Re: Lom-List: Fuel Mixture
>
> Three pints seems impossible. Did you drain that from the pump, or from
> the screen at the rear of the camshaft housing?
>
> Steve
> --
> Stephen Beaver
> Tel: 614-937 4189
>
>
> On Aug 23, 2020, at 10:33 PM, <mike@vision499.com> <mike@vision499.com>
> wrote:
>
> Hello Steve,
>
> I drained the oil from the fuel pump. I removed the plug and oil came out
> very slowly so I left it overnight. Fortunately I put a small container
> under the drain hole as this morning I found that about 3 pints had drain
ed
> out.
>
> I cannot imagine where there is room for that amount of oil. Could it be
> that my scavenge pump is not doing it=99s job?
>
> Have not tried to start it again but will let you know
>
> Thanks
>
> Mike
>
> *From:* owner-lom-list-server@matronics.com <
> owner-lom-list-server@matronics.com> *On Behalf Of *sjbeaver
> *Sent:* August 18, 2020 10:00 AM
> *To:* Lom-List Digest Server <lom-list@matronics.com>
> *Subject:* Re: Lom-List: Fuel Mixture
>
> Mike.
>
> There are no o-rings in the fuel inject system to be concerned about and
I
> would suggest that you do not disassemble it. It is a complex and very
> precise device! - What you might do, however, is remove the drain plug on
> the underside of the unit and allow any accumulated oil to drain out. If
> sitting for a long time excess oil can accumulate in the pump and interfe
re
> with the mixture.
>
> Let me run through some of the other items you might check. I am not
> implying that there is any part of the manual you have not digested. Just
> making sure I don't omit anything :)
>
> First and foremost (If I had a $ for every time I explain this . . . ) i
s
> the automatic mixture system. People used to operating American engines
> seem to think that the engine should always be operated at the most rich
> setting available. That is just not the case with the LOM and doing so so
> will have serval rather bad consequences.
>
> Look closely at the mixture control arm that extends from the side of the
> fuel injection pump. There is a slot in the arm, inside of which is a sma
ll
> pointer. Also on the side of the pump is a shiny metal plate shaped like
a
> pizza slice on which are marked the mixture settings. Something like +3,
> +2, +1, N, -1, -2 with the -2 being nearest the top. Adjust your mixture
> control mechanism so that the "normal" (all phases of operation below
> 10,000') corresponds to the pointer being aligned with the 'N' mark. -
> Actually 'N' inside a circle. Now you know the mixture is set exactly as
it
> should be. Again - do not operate the engine at the full rich setting.
> Doing so will disable the automatic mixture system, foul the plugs, wash
> lubricant from the cylinder walls and other bad things.
>
> Next, start the engine and let it warm up for an extended period. When th
e
> oil temp is up in the 100F area, carefully and with the appropriate
> precautions run the engine at full power (super charger engaged) Switch
> from both to magneto 1. What RPM drop do you see? Go back to both, then
> magneto 2. Again, what RPM drop do you see? I would expect a drop in the
> 25-35 RPM area. Anything other than that suggests your ignition timing is
a
> little out. It is a simple matter to loosen the magneto clamps and rotate
> the mags a little until the 25-35 RPM drop is observed. Why not just time
> the mags with a buzz box in the traditional manner? For two reasons: 1)
> This is how the manual says to do it and 2) these magnetos have automatic
> advance and retard systems so static timing means almost nothing.
>
> How that the mixture and the ignition timing are up to snuff, you can do
> some testing. Operate the engine for as long as is reasonable at a cruise
> sort of power setting. Say 25" of manifold pressure. (It doesn't matter i
f
> the super charger is engaged or not). Now shut down and observe the exhau
st
> pipes. Are they back and sooty, a very light gray (almost white) or a nic
e
> mid gray, the color of a slate roof? - We want the slate color.
>
> If in doubt, remove the spark plugs and see what they look like.
>
> Another useful trick (if you have straight pipes) is to run the engine in
> the dark and look into the exhaust pipes of the running engine. At medium
> power settings look for a nice blue flame tinged with yellow to indicate
> the ideal running conditions.
>
> Finally, since I see you are in BC, you could contact Pavol Novak who now
> resides at Qualcom Beach on Victoria Island. He is a Czech LOM factory
> trained technician and expert on the engines (and Zlin airframes)
>
> Steve
> --
> Stephen Beaver
> Tel: 614-937 4189
>
>
> On Aug 18, 2020, at 12:14 PM, <mike@vision499.com> <mike@vision499.com>
> wrote:
>
> I have the 4 cylinder engine with supercharger, fuel injection and
> automatic mixture control. The motor was factory reconditioned in 2003 an
d
> has had
> Zero hours since
>
> I started the motor recently and there are loud =9Cpops=9D ou
t of the exhaust.
> An AME on the field thought that it was running lean.
>
> Fuel pressure is good
>
> I see that I can adjust the mixture at the fuel pump but want to ask if
> there is something else I should check for first.
>
> Has anybody opened the fuel pump, are there any seals that would have
> deteriorated. From the drawing I cannot see if there are any seals that m
ay
> need replacing.
>
> Thanks
>
> Mike
>
> Mike Pienaar
> *m*ike@vision499.com
> *Home: +1 250-999-8121*
> Mike cell: +1 250-885-0554
> 1-1100 Tulip Ave, Victoria, BC, V8Z 0A2
>
>
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