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Eliacim.
You are stating in your initial summery that besides replacing one cylinder,
you also replaced quiet a few things on the ignition system.
Like previously mentioned. I'd replace the things that got changed with
known good ones first.
E.g. replace both magnetos and ignition harness with a good known used one.
Borrow one from a good running plane.
Then second, John Cooper mentioned that the pushrods might be exchanged on
cylinder 1, resulting in not allowing cylinder 1 breath as much as needed
for higher RPM. Has that been checked?
Hartmut
----- Original Message -----
From: <[EMAIL PROTECTED]>
To: <[email protected]>
Sent: Monday, July 24, 2006 3:46 PM
Subject: [COUPERS-TECH] Low power saga
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advice in this forum.]----
Update on low power problem
As you may recall, my C-75 is not reaching static RPM after the following
work:
cylinder 1 was removed and reinstalled to replace a helicoil, installed a
new
ignition harness, 5 new plugs, a new magneto gear and a new impulse
coupling.
RPM maxes out around 1800 RPM (sometimes higher, sometimes lower)and the
engine gets a little rough. If I pull the mixture full out (lean), RPMs
increase about 100 RPM, indicating the engine is running rich. As the
engine
gets warmer, RPMs drop further.
While troubleshooting this we have found / done the following:
a. primer is not leaking
b. intake gasket on cyl 1 is in place and not obstructing air intake
c. mixture plates have been cleaned several times
d. Spark plugs were tested and cleaned
e. carb heat box has been inspected for proper operation
f. Mixture, carb heat, and throttle control travel and operation are fine
g. fuel flow from header tank to carb is unrestricted
h. Magneto timing was checked like 3 times.
i. Compression is good on all 4 cylinders.
j. throttle cable is not slipping
k. replaced air filter
You have read most of that in my previous postings. What follows is an
update.
1. Installed the carburetor after a second A&P disassembled and cleaned
it.
Same problem.
2. Borrowed a good spare carburetor from yet a third A&P, installed it.
Same
problem.
3. Opened Cylinder 1 valve cover and switched the pushrods around. Same
problem.
As hard to believe as it is, I think we can rule out the carburetor.
My A&P gave up and told me to contact the third A&P and have him
officially
take my case. However, the third A&P is in another airport... Not like I
can
tow my plane there...
All that's left in the Contiental troubleshooting list is:
scored valve stems, warped valves, worn cylinders, pistons and/or pistion
rings, worn cam lobe...
I will do whatever the third A&P tells me to do, but I will also
appreciate
any more ideas from the Ercoupe group.
Regards
Eliacim Cortes
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