Rough O-200

[Tom Downey]

Tom, I and others on this topic should accept your diagnosis. The trouble must lie with the first carb, the overhauled one,just as you say, even when it is no longer on the airplane, . Why couldn't I see that all along,rather then trying to have a logical discussion about the symptoms and what had already been checked?
And Im glad we disagree, if you agreed with me, I'd assume that I was wrong and change my opinion. And I dont have much experience with engines, other than Air Force mechanic school and owning and flying three small 4 cylinder Lycomings for 10 years or so, unless you count the decades of partial working on engines from small single cylinder to V-12s, in motorcycles, cars and airplanes.
So it must be the carb that was overhauled, and even when it is not on the engine, it must have left negative vibes, that only occur under 1200 rpm.
I am having some trouble with my car, a miss or cutting out a low speed. I took it to the shop and told them it must be the overhauled carb, and they looked at me kind of funny and claimed it had fuel injection instead of a carb. Im going to try another shop that might be able to find the defective carb hidden in that engine.
We once actually had trouble with an ovehauled carb on a SNJ, got it back from the oh shop and while the plane would start and run it would die at idle, Turns out the oh shop does a lot of duster engines which spend a lot of time idling and the shop had set the float level like they do in dusters, thus too lean for the SNJ.

And what does all that have to do with the ability to trouble shoot on line? All my years dealing with customers has taught me the only way to trouble shoot any problem is to do the whole job yourself. Step by step, square 1 step 1 to finish, Believe it or not you can't do that thru the computer screen. So don't get all up tight because somebody calls you on it.

[Tom Downey]

Gentlemen;
I have been to the Flybaby website and reviewed every condition I thought held some merit. I have recently installed the wings onto the airplane.
I have run the engine once since then. The miss and vibration were NOT as predominate as it was with the fuselage alone. Larger mass absorption ?? I have run several airplanes without wings that had small Continentals and did not experience this type of miss. At this point, all I can figure is that, mechanically (other than a possible lifter problem), there is nothing seriously wrong with this engine. Hopefully will fly I the next 30 days and re-evaluate.

PS: about the carbs. The original carb a 10-4115-2, I overhauled (A&P / IA). The second carb a 10-4894, overhauled in 1997 by Consolidated Fuel Systems and has 500 hrs SOH.

You do realize that the 0-200 with its remote mounted carb, is a known ice maker. they do make ice at idle on the ground.

At next run, feed it some hot air, use a hair dryer if need be.


have you run a cold cylinder test?

[Bill Greenwood]

I dont have much experience working on 0-200. mine is a C90, the predecessor to the 200. . And are vast differneces between C-90 and 0-200 and the small Lycoming 4 cylinder engines?

As for the difficulties of diagnosing on line, we dont have to do that, youve already done it and it was the carb overhauled by someone else, that must be the problem.
As for dealing with customers, Eric as an A&P/IA himself is more qualified than just a pilot owner.

For now, we can Politely disagree on the cause, hopefully without rancor or personal insults and maybe Eric will soon find definitley what the defect is.
And it is possible that both carbs, even though overhauled or to use your term rebuilt and by different people are defective, they could have some gum from fuel in the idle circuit.

I realize that although I like a good discussion of the facts and theories, that some people are not made that way and get uncomfortable with it. I do want to know the final answer to this riddle even if we may not get it.

[Eric Brown]

Next, how can any A&P rebuild a MA3-SPA carb and call it overhauled?
read FAR 43.2 and tell me how any A&P in the field can test it as required by the overhaul manual.[/QUOTE]



If you state that you overhauled in accordance with the current overhaul manual, you are in compliance with FAR 43.2. There is nothing so specialized in the MSACSM, rev 1 overhaul manual that can't be performed by a GA shop. Not all specialized tools will be needed. Equivalents can be found for those tools that are needed. The M-5 float gauge will be needed. The float valve and seat test can be performed with fuel in a standpipe and 6 psi of air pressure.
What part of the overhaul requirements would an A&P not be able to accomplish ?

[skyfixer8]

I would like to throw my 2 cents worth into this post about the carburetors. Although both part numbers that were given . 10-4115-2 and 10-4894 are correct for the TCM O-200. the 10-4115-2 was superseded long ago by the 10-4894 which , if overhauled by a shop should have been upgraded to a 10-4894-1 or -2.

Bill L

[Tom Downey]

Next, how can any A&P rebuild a MA3-SPA carb and call it overhauled?
read FAR 43.2 and tell me how any A&P in the field can test it as required by the overhaul manual.

If you state that you overhauled in accordance with the current overhaul manual, you are in compliance with FAR 43.2. There is nothing so specialized in the MSACSM, rev 1 overhaul manual that can't be performed by a GA shop. Not all specialized tools will be needed. Equivalents can be found for those tools that are needed. The M-5 float gauge will be needed. The float valve and seat test can be performed with fuel in a standpipe and 6 psi of air pressure.
What part of the overhaul requirements would an A&P not be able to accomplish ?[/QUOTE]

Kelly now owns the production certificate, they do not supply the overhaul manual for their carbs. any manual you see is a old Marvel or Precision manual, and no longer used. Kelly is now the only one that can legally overhaul the carbs by the manual. then test as required on a flow bench. the rest of us can only repair.

[Eric Brown]

Even though Kelly does not supply an overhaul manual, earlier manufactured carbs can still be overhauled under the older Marvel and Precision Aircraft overhaul manuals. In a decision out of the 1990's, the FAA considers the earlier manuals to be "current data" as long as the carb was manufactured during or before the time that the earlier manual was current. This would make an overhaul of an earlier manufactured carb to be in compliance with FAR 43.2 and 43.13(a). The only additional requirements for the overhaul would be the compliance of ADs issued against the carb up to the date of overhaul.

Now, ...... a civil court may have a different opinion !

[Tom Downey]

Even though Kelly does not supply an overhaul manual, earlier manufactured carbs can still be overhauled under the older Marvel and Precision Aircraft overhaul manuals. In a decision out of the 1990's, the FAA considers the earlier manuals to be "current data" as long as the carb was manufactured during or before the time that the earlier manual was current. This would make an overhaul of an earlier manufactured carb to be in compliance with FAR 43.2 and 43.13(a). The only additional requirements for the overhaul would be the compliance of ADs issued against the carb up to the date of overhaul.

Now, ...... a civil court may have a different opinion !

Nice,, now where are ya going to get new parts for them?

[Bill Greenwood]

Eric, since Tom has been doing 0-200 work "for 60 years", perhaps he has a current overhauled carb for them, maybe even a Kelly one, that he would loan you to try on your engine, with the agreement that if it cures your miss, then your carb was indeed the problem and you pay Tom a generous price for his carb plus shipping. If not you return it as received, paying shipping both ways.
I want you to fly safely when and if you do get in the air, but Id also really like to know the answer to the riddle.

[Tom Downey]

Just buy a new one.