Earthstar Forums

Kess and Alan,

Engine was working hard and had for just over an hour. We were at gross, 5500 ft
out and 6500 ft back, cruising at 85-95 mph. But it was cool, about 60 degrees
F.

No internal damage seen through the exhaust port. In fact, engine looks new, no
carbon.


No sign of wiring problems for mags.

I am running an HAC system, which I calibrated last fall when I rebuilt carbs
with new floats, float valves, and new needles and jets per recommendations on
Green Sky website. Went from 8L2 needles, top groove, 2.74 needle jet and 158
main jet to 11K2 needle, second groove, 2.70 needle jet and 185 main jet. Runs
great and plug colors are spot on.

I also replaced all the fuel lines at that time, moved the Facet electric
pump to inside the rear compartment (it was facing into the passenger seat !!!)
and configured as a parallel system with fuel line from tank split with one side
going straight to Mikuni and other side to the Facet and then Tee'd into each
carb fuel line coming out of the Mikuni. It's ugly. It has tiny bubbles. I used
small worm gear hose clamps inside the fuel tank compartment and safety wire
2-turns clamps outside at all the connections.


Mark told me how to check connectors for flaws that can cause air leaks and he
thinks there should be no bubbles in the system.


New plan is to change the fuel line system to a simply Series system with a
single line that comes from tank through a filter to the Facet pump, then to the
Mikuni and then to the carbs. I used a small clear plastic fuel filter with a
brass-colored filter element inside, from Aircraft Spruce. (I'm lucky enough to
be able to shop at the counter at Aircraft Spruce, where the staff is very
helpful to deal with.)

(If I had thought to turn on the electric fuel pump when incident happened, my
parallel system could have been put into operation and would have told me
whether fuel starvation was the cause. However, I have read so much about
seizures and we've had several recently at my airport that my focus was
completely on whether my engine was seizing. You can be that pump on will be the
first action in any future in-flight engine problem)

I'm also going to replace the plunger primer, which is in the passenger
compartment at the sill at front edge of door where I can reach behind me to
operate it. (It's possible that the passenger movements may have raised the
plunger slightly during that flight.)  One of the guys at my airport theorizes
that the carbs could have drawn fuel through the primer system in little spurts
which caused the power losses. I believe the plunger is worn because lately it's
taking me 8-10 pumps to prime the engine for immediate start.

But the bottom line is that right now there is no smoking gun. I think I'm faced
with tweaks like these and then a lot of test flying to prove to myself that the
plane is reliable.
 Dick O'Reilly

Dick,

My plane was plumbed with the Facet in parallel with the engine pulse pump also, but when I replaced all of the aged tubing I chose to re-plumb in series. My thought was that the two pumps are pushing against each others check valve, and if either fails, the engine will quit as there is no back up. At least in series, there is no way to lose pressure. I know some may dispute this and continue to plumb in parallel, and that's their choice. I also have a problem with the Facet pump being elevated, and not at the very bottom of the tank level, as that would require a bottom hole in my precious 10 gallon polyethelyne tank. Maybe I should get over that and put a hole in it, that way I could also build the fuel level gage using tubing.

kb

Kess
Get your drill out and go for it.
I would like to see how you make out.
I have no idea how you would make a gas tight fitting in the tank.
A sight tube would save buying a camera and such. A mirror would be all that you need.
I am sure your Titan buddies would be happy to drill a whole in your tanks.
Fred

Kess,

I think Fred is writing with tongue far inside his cheek and really means "no
way". I certainly do. At least ask Mark before you drill.

As for the Facet, mine is mounted at the bottom of the fuel compartment opening
in my JT2, so it has to suck fuel out through the top of the tank, down to its
position 12-15 inches lower and then push it up to the carbs.  So how well does
it do that? Superbly. And I watched that first hand last week as I used the
Facet to pump the last four gallons out of my tank into a Mr. Funnel to a 5
gallon can so I could check for water in the fuel and see how far down the tank
would actually empty. No water and only about 1/4 inch visible fuel remained.

It pumped at a rate of about a pint or two a minute I'm guessing.

So I think you should leave it alone.

Check out this article: www.challengers101.com/FuelSys.html 
You need to look at the Google cached version because the original is gone. It
plainly states there is no reliable way to seal an outlet in the bottom of a
plastic tank. It's also got a lot of other good info about fuel systems on
ultralights.
Dick O'Reilly

In a message dated 5/5/2011 11:13:10 PM Pacific Daylight Time,
alan.cossitt@frontier.com writes:

I know others have had problems at high altitudes due to low fuel
pressure. Why the have elec. Fuel pumps to back up mechanical.

-Alan Cossitt

>From my iPhone. Please excuse typos and terseness.

Hi Dick
Since you dident turn on the electric fuel pump you would be better off
removing it. It may be the cause of your problem in that the connections will
leak if hose clamps that have a werm drive are used instead of the
preferred method using the safety wire. You could replace the hose clamps with
safety weir and that may well end your problems of the air in the fuel line as
evidenced by the bubbles.
This is your smoking gun!
Happy Flying
Mark

In a message dated 5/6/2011 9:49:36 AM Pacific Daylight Time,
kessb@wavecable.com writes:


My plane was plumbed with the Facet in parallel with the engine pulse
pump also, but when I replaced all of the aged tubing I chose to re-plumb in
series. My thought was that the two pumps are pushing against each others
check valve, and if either fails, the engine will quit as there is no back
up. At least in series, there is no way to lose pressure. I know some may
dispute this and continue to plumb in parallel, and that's their choice. I
also have a problem with the Facet pump being elevated, and not at the very
bottom of the tank level, as that would require a bottom hole in my precious
10 gallon polyethelyne tank. Maybe I should get over that and put a hole in
it, that way I could also build the fuel level gage using tubing.

kb





No, don't put a hole in the bottom of your tank. Just put you electric pump
that is not needed any way down low since this will work to prime it. all
my flying with the 503 was done without the electric fuel pump.
Happy Flying
Mark

In a message dated 5/6/2011 10:02:46 AM Pacific Daylight Time,
gayford@golden.net writes:

Get your drill out and go for it.
I would like to see how you make out.
I have no idea how you would make a gas tight fitting in the tank.
A sight tube would save buying a camera and such. A mirror would be all
that you need.
I am sure your Titan buddies would be happy to drill a whole in your tanks.
Fred




Pleas don't
Happy Flying
Mark

I would like to add to Mark's comment. I had bubbles too shortly after I bought the plane. My fuel lines were aged and hard, and I was lucky that I never had an engine stoppage. I replaced all of the lines, including the pulse line fron the crankcase. I used a specfic clear tubing for pulse lines, and the official Bing blue fuel tubing also, all from Aircraft Spruce. No bubbles after that as I also removed about half of the plumbing with the parallel fuel pump thing that is now in series.

I was only half kidding.
I thought a sight tube would be a good idea.
I figured there must be a way to make a liquid tight fitting in the lower part of the tank.
I was looking at the bottom of a tank on a ultralight at the field the other day and looked at the fittings. It was a press fit rubber like grommet with a ridge on the tube inserted into it which expanded the grommet to make the seal. The tank had three of them.
There must be a way. What do you think?
Fred