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1. 01:18 PM - Re: Fuel Mixture (sjbeaver)
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| Subject: | Re: Fuel Mixture |
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
enough. 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 between 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
<mailto:owner-lom-list-server@matronics.com>
<owner-lom-list-server@matronics.com
<mailto:owner-lom-list-server@matronics.com>> On Behalf Of sjbeaver
> Sent: September 7, 2020 12:39 PM
> To: lom-list@matronics.com <mailto:lom-list@matronics.com>
> Subject: Re: Lom-List: Fuel Mixture
>
> Mike,
>
> Those are interesting results! You appear to have the older style pump
and you are correct that it should be serviced with engine oil up to the
level 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,
but 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
<mailto: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
this 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 +/- 60ml
>>
>> 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 nozzle.
>>
>> 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 then checking if oil runs out of the sump plug cam case plug.
Not sure if there is a direct connection, but there must be something
that stops the cam case 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
<mailto:owner-lom-list-server@matronics.com>
<owner-lom-list-server@matronics.com
<mailto:owner-lom-list-server@matronics.com>> On Behalf Of sjbeaver
>> Sent: August 24, 2020 5:08 AM
>> To: lom-list@matronics.com <mailto: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 the older style pump with a filler port on the side, perhaps a
cup. Then again 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
suggest all is well. If you see almost none then it would appear that
the cam case oil is somehow leaking into the injection pump. This seems
unlikely though
>>
>> 2. Put everything back together and run the engine. Asses
the performance per my previous email and then remove the oil drain plug
in the pump again. How much oil this time? (Use something more
scientific than the hangar floor to measure it :) )
>>
>> Steve
>> --
>> Stephen Beaver
>> Tel: 614-937 4189
>>
>>
>>
>>
>>
>>> On Aug 24, 2020, at 12:04 AM, <mike@vision499.com
<mailto:mike@vision499.com>> <mike@vision499.com
<mailto: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 the 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
<mailto:owner-lom-list-server@matronics.com>
<owner-lom-list-server@matronics.com
<mailto:owner-lom-list-server@matronics.com>> On Behalf Of sjbeaver
>>> Sent: August 23, 2020 7:57 PM
>>> To: lom-list@matronics.com <mailto: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
<mailto:mike@vision499.com>> <mike@vision499.com
<mailto: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 drained 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
<mailto:owner-lom-list-server@matronics.com>
<owner-lom-list-server@matronics.com
<mailto: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
<mailto: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 interfere 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 . .
. ) is 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 small 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 the 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 if the super charger is engaged or not). Now shut down
and observe the exhaust pipes. Are they back and sooty, a very light
gray (almost white) or a nice 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
<mailto:mike@vision499.com>> <mike@vision499.com
<mailto: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
and has had
>>>>> Zero hours since
>>>>>
>>>>> I started the motor recently and there are loud =9Cpops=9D
out 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. =46rom the drawing I cannot see if there are any
seals that may need replacing.
>>>>>
>>>>> Thanks
>>>>>
>>>>> Mike
>>>>>
>>>>> Mike Pienaar
>>>>> mike@vision499.com <mailto: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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