O-200, Please Explain (2024)

Hi all,

Been looking for a 7ECA for a flying club and I am wondering what there is to know about the 100hp O-200 engine. What is the TBO? Do they go to TBO? Are parts available used or new? What are the weak points?

Thanks in advance!

The O-200 is limited to a few model years so you are looking at the "no bounce gear".
The engine itself is proven over the years, TBO is 1800/2000 dependent on s/n.
Expect a top overhaul between 900 and 1200 hrs. YMMV.
Like any other, much depends on usage and treatment.

If doing aerobatics, time between maneuvers to regain altitude is extended.

The C-85 has been known to go 4000 hours without any kind of overhaul. I used to have problems with exhaust seats, but if you get the correct seats they go seemingly forever. A lot of shops will do a complete top overhaul when one cylinder goes limp - I have found that about half the time a weak cylinder will come back up after a week of touch and goes.

The O-200 is simply a C-85 with a slight stroke and different cam.

My Cessna 150 uses an O-200A, they like to gum up valve guides every 300 hrs or so. You'll see people online pushing the use of "the rope trick", it fixes nothing and is only a band-aid solution. The proper fix is to ream the valve guides, it can be done by a

without removing the cylinders. Most O-200 guys swear by a little glug of marvel mystery oil in the fuel to help alleviate the problem.

The O-200

mogas, I typically mix Avgas to Mogas at a rough 40/60 ratio.

The bottom ends are known to be strong but the old continental cylinders can get a little soft. Although 68/80 psi would not scare me away from an O-200, anything lower is getting concerning. New Millennium cylinders will tighten an old O-200 top end nicely.

The oil pump gears can get a little out of tolerance and the pump loose its prime if not flown regularly. It's annoying but can be re-primed by removing the filter (if equipped) and squirting some oil into the orifice. If not equipped with an oil filter the oil change interval is cut in half to 25 hrs and screen must be cleaned every oil change.

I've never experienced carb icing in my Cessna but I know people that have and generally it is agreed the O-200 makes ice like a Frigidaire. Proper use of carb heat is important.

Parts are readily available, but nothing is cheap these days.

TBO is 1800 hrs, as a previous poster mentioned the old continental cylinders will likely need at the very least rings around 900 hrs.

The O-200A citabria has an exhaust system that maybe hard to find parts for, I've seen them modified to accept champ / Cessna 150 style exhaust systems. I am not sure if this would be a legal repair.

I've only done one circuit in an O-200 equipped 7eca Citabria and I liked it, I kind of regret not buying it. It didn't have power to spare but it was adequate at near sea level with two adult males and 15 degree C day to climb at 500 ish fpm.

Hope this helps

I have no experience with a 7ECA, but worked on plenty of Taylorcrafts and Champs with the O-200.

Great little motor, I concur with Norm. And highly recommend autogas in them, far less fouling and related problems.

Fully supportable engine.

I would have no problem owning one.

Thanks @Tangogawd for chiming in.

The only alarm that I hear going off is that autogas is not fully compatible with Stewart Systems fabric/paint. The outer layers are ok with it but if autogas gets behind the covering it will bubble it from the inside out.

Good to know they're good engines.

Bart,

I would chime in with a few points, like everyone else has said, lead is the big problem. I too am a marvel oil believer.

If you end up doing a auto fuel, 100LL mix in any aircraft and it is going to be down for a few weeks or more, try to run the auto gas out of it on the last couple of operations.

Many operators of the Cessna 150's are students with the 0200 and they are an afraid to lean the engine. You really have to lean the crap out of them especially on the ground where they are running cold. The lead component in 100LL will not completely scavenge it self out of the engine until the EGT's are in the 1100 plus range and closer to 1150. At that point the bromide lead component is in a more gaseous state and leaves the engine. Which is another good argument for full engine monitoring.

Auto gas these days is about as perishable as it gets and it will muck up a carb if it sits for any great length of time. For that reason I have issues with running anything lower than a 50% mix of 100LL to auto fuel, unless you are running non stop day in and day out.

Cheers, Brian