Engine fixed

[btbell]

We ended up having to pull the cylinder and clean it up good. There was a ton of carbon deposits, which we determined were hanging the exhaust valve up. Anyway we cleaned her up and reassembled her and she ran great except for the leaky carb. We tore that apart and found the seat had a bunch of nicks in it. For temporary use, we reseated the valve and then she worked great. I will be ordering a kit to replace the needle and seat as we anticipate it will start leaking again.

We ran her and then I flew her and found that she was still loading up a bit during idle. I noticed it when I advanced the throttle for takeff. She ran rough for about 3-5 seconds and cleared up. We reset the idle mixture about halfway between rich and lean.

I am glad to have an A&P that was willing to work with me and supervise me doing the work. I learned a ton this weekend!!

Couple more questions for anyone in the tribe:

1. Any other tips for the carb to keep it from loading so much during idle? Can I run it more lean than it is already set?

2. Does anyone use Marvell Mystery Oil?

3. I imagine the other 3 cylinders are pretty carbon filled also. Any tricks to burn this carbon off?

4. Anything else I am missing?

Thanks for everyone's help!

[jgerard]

I used up 1-qt. of MMO by mixing it with the fuel and oil in my A65 for most of my 37-hr trip across the country. I did notice some carbon flakes on the oil screen during the oil change, and I picked up some compression in all the cylinders. I still have one cylinder that is lower than the others. I can feel it when pulling the prop through before startup.

Good luck with the carb. Do you run Auto fuel?

Jason
N43643

[Jim Hartley]

no more problems

I too experienced loading up and carbon particles in plugs and difficult hot starts which can be a chore in a hand propper.

I use a mix of 1 part 100LL to 3 parts unleaded. I have 150 gallons unleaded and 50 gallons 100LL delivered to my 300 gallon storage tank. I add the amount of MMO per directions to each five.

No more problems and it generally starts on the first pull cold and always on the first pull hot and no more carbon.

[btbell]

Well I was still running pretty rough at idle today so I leaned it a bit more and adjusted the idle speed to compensate. She runs great now. Flew about an hour and a half with no additional problems.

To answer Jason's question, I do run auto fuel. I have run whatever has been available where I have been and probably over the last 6 months have run more 100LL than auto. I will be running more auto now since the airport where I am hangered does not have fuel so I will bring my own. I will occassionally be running 100LL when away from home.

I will have to check out the MMO. Anyone else that uses it please share your experiences and mix ratio.

Great stuff Jason and Jim - Thanks!!

Brian

[jgerard]

make sure to only run non oxygenated fuel. You don't want that alcohol in your plane. A quick way to check is to take a clear container (your basic airplane fuel sample tube/screwdriver) add some water (about 1/2"), note the level of the water in the container (it may help to make a line on the outside of the tube), add some fuel, if there is alcohol in the fuel it will mix with the water in the container and the level of the water will rise. We all know by now that water and fuel don't mix so there will be a definite line in the sample container. Auto fuel has lots of additives that 100LL does not so choose your fuel wisely. Most of your local car gas starts at the same refinery but each brand has it's own cocktail of additives that gets mixed into the bulk load. Ask some of the gas stations in your area to provide you with a list of what is in each grade of their fuels and compare.

Jason
N43643