Is here any mechanic familiar with this engine? I mean with fuel system exactly? I think (well it is obvious) my engine is running rich. exhaust is black, spark plugs are black, and consupmption is higher than it should be due to FF indication. I mean on full rich settings.
One manual says, that injected engine testing is done on 1000rpm (rise between 25-50 rpm when leaning), and service bulletin says it should be done on idle.
But my friend, also mechanic, told me, that injected engine should be tested on 1000rpm, carburated engine should be tested on idle. Now where is truth? I have right setting on 1000rpm (rise around 30rpm), but on idle it is arond 100rpm (too rich). Well now where I shoud to test this? It should be done in every 100hr check.
This is SID, that says it should be on idle: https://www.academia.edu/37772987/SID97_3C_ADJUSTMENT_OF_Continental_Fuel_Injection
Page 6 of 40, step 19
The TCM fuel set-up is a 100hr recommended item and very few people have the kit to do it. It requires either TCM Porta Test Kit or some calibrated digital gauges which we bought costing circa 1k. You need a Dwyer DPGWB-08 for reading the unmetered fuel pressure and a 490-A2 for the metered fuel pressure. We bought the two MS51523B4 T-Fittings to have and made some hoses. Something like a TruTach optical tacho is really handy too.
Lots of people like to mess with the idle mixture, as it’s easy to do and you can in theory use the OEM tacho. If you do the full process and have the worksheets available it says a lot to the next owner about the way you cared for your engine.
Well I understand that, and clearly have to check this with someone who has right tools, maybe I will buy it, I saw few older test sets, not digital, but accurate steam gauges, but I am talking about testing. This test can do anyone as a preflight, or so, but it is not clear to me how to do it. Should I do it on Idle (cca 650rpm), or on 1000RPM?
SID says:
“With engine operating at the specified IDLE RPM and unmetered fuel pressure, slowly move the mixture control from the FULL RICH position toward IDLE CUT-OFF to check fuel/air mixture. A rise of 25 to 50 RPM should be obtained. An RPM change greater than 50 indicates the mixture is too rich and a change that is less than 25 indicates the mixture is too lean.”
BUT, engine manual says it should be done at 1000RPM. If I do it both ways, there is very significant difference.
The text above speaks about SPECIFIED idle. Is is really nowhere specified in that long doc?
In my experience, in the context of these aircraft engines, the word “idle” is often used incorrectly. People very often speak about “idling at 1000 RPM” or similar, which is obviously sort of a contradiction, as “full” idle is usually somwhere somewhere at 500 RPM (and very “spluttery” in the flat fours and flat sixes).
Not sure this is the case here. Again, they should specificy the idle somewhere if they mention it.
Jelen wrote:
Should I do it on Idle (cca 650rpm), or on 1000RPM?
1000rpm
Well now I found in tables there is specified RPM with specific pressure. Now only have to check pressures by any mechanic with gauges and figure out why is it rich.
Thanks William, this is also what my friend said.
Anyway table 3 says idle is 600RPM for IO-360D, it says 1000RPM for IO-240. I will keep reading again and again, until I find those 1000RPM everyone is talking about. :)
Well, I am not a mechanic, but if your test is OK at 1000rpm and the engine is still too rich, maybe the test setup isn’t right 
And the SID is most probably younger than the engine manual, so maybe something was learned by the time it was issued.
It reminds me of a friend who had an engine stoppage during the flare in a Reims Rocket (IO-360H). They stopped on the runway and the engine restarted after many attempts. The club mechanic found no issues except the super dirty plugs, complained about pilots who can’t make thses engines work etc… (you get the usual french grumbling 
)
The engine was running so rich it had stopped !
Maybe stating the very obvious, but in a Reims Rocket, the aux fuel pump should not be on (neither hi nor lo) during normal takeoffs and landings, nor should it likely be during this test….
vic wrote:
On a high wing aircraft there is no need for an extra fuel pump I´d say.
Not even if the engine is fuel injected? (Which the Reims Rocket engine is.)
