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USCANAM

Well Known Member
Over 40 hours on my 9A now, so am ready to tour the world.
We have a Superior Parts Lycoming Type IO-360 (180 hp.) built by Penn Yan with vertical Fuel Injection, 3 blade MT constant speed.
Engine was pretty well broken in on the test cell at Penn Yan. Burns less than a quart / 10 hours of mineral oil which we will change this week to AD.
Only problem we've had is loading up when taxing out to our long runways. Mixture is just about all the way out when taxing.
Had to abort my wifes first flight the other day and take the bird back to the hanger, pull the cowls and plugs and clean the plugs.This was the first cleaning. Plugs were wet when pulled, but couldn't really tell with what using the smell test. Talked to Penn Yan, and they felt it was fuel and oil.
I have a One Design Aerobatic plane with a similar engine/prop setup, except it has horizontal fuel injection.
When landing the One Design, and every other plane I've landed with fuel injection and C/S prop, I've always had the mixture in full rich when landing (assuming a low sea level airport. My airport is 80' msl.) The One Design pops a bit when throttle is fully closed, but runs smooth. The 9A with about 15" M.P. for the pattern, seems to miss a lot with full rich. I haven't tried a landing in a leaned out condition. Just wondering if anyone else does stay lean when landing.
I have a brand new set of Iridium plugs to go in with the next oil change. My Mooney never fouled a plug when I used these, and that was over 2000 hours. I used the same set of plugs in 3 engines!!
I'm hoping this will help the 9A.
Any comments?
Thanks
Jack
Finally got all the wheel fairings on. Tip....if you have any A model, do the fairings before you put the wings on!!
 
Are you running an auxillary fuel pump....Check the fuel pressure??? Curious, and probably irrelevant, but are you using different fuel sources, or do you fuel up at the same tank/FBO
 
On taxi and long decents I stay well leaned or load up with lead. This is why I'm exploring auto fuel in my plane along with economic issues. But on topic, I lean in the pattern and part of my go around checklist is to add mixture as needed. I will lean to what I'd guess is best power or slightly less (full rpm then lean till it stumbles and richen till smooth). The engine will give full RPM without stumbling at this mixture setting so go around is no problem. Just have to richen for climb cooling which is NOT an emergency need.

Uses less fuel, oil stays clean longer, throttle response is improved if I have to add power, plugs don't foul. just have to remember to go rich for extended climb.

If this is wrong I invite the reasons.
 
USCANAM said:
Only problem we've had is loading up when taxing out to our long runways. Mixture is just about all the way out when taxing.
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I suggest adjusting your idle mixture so that it is correct in the full rich position so that you dont have to futz with leaning on the ground


erich
 
erich weaver said:
I suggest adjusting your idle mixture so that it is correct in the full rich position so that you dont have to futz with leaning on the ground


erich
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Erich
Good point, but common instructions are to adjust idle mixture so rpm increases about 50 when shutting of engine with idle cut off. I've been turning the adjustment thumbwheel very carefully to achieve this.
We'll try keeping lean in the pattern to see what happens. Feeling the engine miss is not a happy sensation.

What I think I'm finding is that the engine does not like to be driven by the prop as in descending down to pattern altitude, My Mooney was very clean and was not a problem with the engine when descending. I'm also starting to think that the 9A is perhaps even cleaner and more of a chore to slow down to 100 mph if a little flap is desired.
Thanks
Jack
 
TerryWighs said:
Are you running an auxillary fuel pump....Check the fuel pressure??? Curious, and probably irrelevant, but are you using different fuel sources, or do you fuel up at the same tank/FBO
Click to expand...
Same FBO and fuel pressure is remaining about 29-30 lbs, whether aux pump is on or off
Jack
 
USCANAM said:
Erich
Good point, but common instructions are to adjust idle mixture so rpm increases about 50 when shutting of engine with idle cut off. I've been turning the adjustment thumbwheel very carefully to achieve this.
We'll try keeping lean in the pattern to see what happens. Feeling the engine miss is not a happy sensation.


Jack
Click to expand...

I don't know what injection system you have...but I am pretty sure the Precision (and bendix) spec is for an increase of between 10 and 30 (max) RPM when the mixture is slowly pulled to idle cutoff with the engine idling at a specific RPM (I think it is 750 RPM but I would have to look it up to be sure).

It sounds to me like you idle mixture is overly rich.
 
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