Paul, do you know if there is something I can add to the fuel to release
stuck apex seals?

I installed new primary fuel injectors but I don't think that has solved
the problem I've been having. Over the last year or more the engine
has been getting more difficult to start and once it starts, runs
on one rotor for a short time before clearing, varying from a few
seconds to more than a minute depending on how long the plane has
been sitting between flights. I now think it might be an apex seal
that is stuck in the cold engine but becomes unstuck after running a short
time.

555 hours on the engine since rebuild.

Perry


There are so called top cleaners sold in auto parts stores.

A typical treatment involves starting the engine and
pouring or feeding the cleaner into the intake manifold,
throttle body. The engine is then shut
off and allowed to soak for a period of time
(typically 20 to 30 minutes). For severe deposits,
additional cleaner may be added through the spark
plug holes. The engine is then restarted to blow
out the carbon. The oil must then be changed to
remove any cleaner that has leaked past the seals
into the crankcase.

Try Sea Foam top cleaner.

I would take the exhaust manifold off and check the apex seals with a
finger. Do that first and then after the cleaner to see if it made
any difference. If it helped do it again.

Also as I recall pull the lower plugs and fill the engine with auto
transmission fluid and let it soak over night. Turn it over with
out the plugs to get it out of there. Then put the plugs back in
and start it.

Try running some high detergent gas through it for awhile. What kind
of gas are you using?


Paul Lamar


Paul,

Can the aircraft bleed-down style compression tester be used on a rotary?

I'd be tempted to try to clean the seals manually with the exhaust
manifold removed (as you suggested).  Squirt some cleaner (solvent,
penetrating oil, etc) on them and exercise them in the slot to scrub
the crud (technical term) off.  Let soak and then exercise them again.

Do side seals get gummed up?

As mechanically robust as the rotary is, could it be an ignition or
injector control problem?   If the seals seem fairly clean and easy to
move, I'd bet more on a systems problem.

Does this airplane have capacity to run lean?  Maybe it is sooted-up
because it doesn't get a chance to clean itself out.  How sooty is the
exhaust?  How about the plugs?


Matt-

You may have hit on the problem. As I recall Perry has no way of leaning
the stock computer used.

Paul Lamar