Cloyd Van Hook, President of BAC,

What the hell is a tree frog? Why would such a creature want to climb into your engine? Are tree frogs on your pre-flight inspection form from Beechcraft? If not, why not? You are a lawyer. Was the tree frog there inserted in Liberal Kansas? If so, you can sue Raytheon, win with a Southern California jury, and all our prices will go up again. Was the tree frog male or female? Was it under 18 years old? Huh? What were you doing with that young tree frog in your hangar --- you pervert!

Tom Corcoran.... enroute to Canada.

-----Original Message-----
From: cloydvanhook <>
Sent: Tue, 14 Jun 2005 17:39:08 -0000
Subject: [musketeermail] Carb problem

Here's the background information.

Minnie is a 1963 Beech Musketeer, Model 23, S/N M-238.

The engine is a Lycoming O-320-D2B, with approximately 3450 hours
TT. It has been overhauled twice in the field and has approx 1120
hours SMOH.

The carb is a Marvel-Schebler Model MA-4-SPA, P/N 10-3678-32. The
logs do not indicate it has ever been overhauled or replaced.

The air filter element and all aero-duct under the cowl were
replaced at the last annual, approx one year to the day and 100
hours ago.

Here's what happened.

Thursday night, 2 June I flew for about an hour and everything was

Sunday, 5 June I went to fly and start up was normal. I taxied to
the fuel pumps and put approximately 10 gallons in each tank to
bring them up to the slots.

I started the engine taxied to the departure end of runway 17 at 1L0
and did a run-up and mag check at 1800 rpm (per the POH for the
plane). On the left mag everything was normal, about 100 rpm drop.
On the right mag the drop was about the same, maybe just a little
more but nothing terribly unusual. Then the engine seemed to run a
little rough. This engine seldom if ever fouls plugs but I leaned
the mixture some and it smoothed out. When I put it to full rich
for takeoff it seemed to get a little rough so I decided not to go.
Taxied back to the hanger and put it inside and decided to run it
again. This time when I would rev the engine to 1800 rpm or so at
full rich it would vibrate so much it would shake the panel. If I
would lean the mixture she would smooth out. Decided this was not

Spoke to some folks who told me it sounded like either the float was
sinking (possibly a hole in it) causing it to run rich or there was
something stuck between the needle and jet not allowing the float
and needle to close off the jet also causing it to run rich and
rough. Suggested I try some high speed taxi to see if it cleared up.

Monday, 6 June I went out and fired her up. Same thing. Ran OK at
first. Mag check seemed OK at first then would run rough. If I
leaned it would smooth out. Would have to pull the mixture knob out
about two inches for it to smooth out. At the end of every run I
would go to full rich, it would run rough. I'd lean and it would
smooth out. With a 4,000 foot runway she was wanting to fly well
before the end of the runway so I couldn't go the whole runway at
full throttle, so I sat on the on the taxiway and ran it at full
throttle for over a minute at full throttle and leaned it was
smooth. After that if I'd go to full rich it would run rough again.

Put her to bed and decided maybe it was time for a rebuilt carb. My
A&P had written down all the data on the carb last annual so I had
the info I needed to order it. I wanted to be sure I had the right
data before ordering so I tried to read it myself. Could only see
the data plate with a mirror and could read the model number but not
the P/N. Decided I'd wait and decowl her and verify the data before
ordering. (Didn't want to give Spruce $559 for the wrong carb and
have a hassle with an exchange.)

Sunday 12 June pulled the prop and cowl (have to pull the prop to
decowl a `63 Mouse if you don't have the split cowl kit installed).
I was copying the data off the plate and my neighbor, a Cessna 150
driver that was giving me a hand, said why don't you take a look in
the carb. I got a mirror and gave it to him while I went to get a
flashlight. He said I see the problem.


So how did that cause the problem? They restricted the airflow
enough to make the mixture too rich at full throttle, even maybe at
half throttle.

So how did they get in? The shroud for the carb heat wraps around
the exhaust pipe between No. 3 cylinder and the muffler. It's open
on both ends to let air (and mud dobbers and tree frogs) in. Then
there's aero duct from the bottom of the carb heat shroud to the
carb. Apparently the butterfly valve wasn't closing enough to keep
them out of the carb. (I still have to check that closer).

Problem solved, I HOPE. She's all back together but it was too hot
to fly her by that time Sunday. I'll take her for a test drive
tonight. She did run smooth at full throttle and full rich after
the mud dobber and tree frog ectomy.

I'll report back tomorrow.

Cloyd Van Hook
President, BAC

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