Help - Severe lead fouling on Lyc O-235 L2C engine

Severe lead fouling has quickly gotten worse over the last few months. Used to get about 20-30 hours on a set of plugs before cleaning, now it takes about two hours to completely foul the bottom plugs. We switched to electronic ignition last week with auto plugs and this did not improve the fouling issue. The bottom plugs are completely filled with lead chunks and the electrodes are also fouled. The plugs do not appear carboned up due to a rich mixture, in fact we have tried to really lean the engine during taxi and flight.

Engine is a Lyc O-235 L2C with a carb. No primer pump. It idles at 800 rpm, I will lower to 600 tomorrow, but I dont think this will help much. It does seem to run a little lean. Pulling the mixture quickly stops the engine, no increase in rpm before shutting down. I dont think richening up the idle mixture will be much help either.

Im beginning to think that this is a carb issue.

I would like to hear any ideas or suggestions regarding this lead fouling issue.

Thanks for your time,

[email protected]

No increase in RPM as you pull the mixture may suggest an improper mixture setting. Consult someone who knows more than me.

I always lean the mixture after start up and while taxiing. Set to correct setting during runup.

Also lean out well after landing.

Lyc O-360, carb

What kind of cylinder head temperatures do you typically see? I've read excessively low head temps can affect lead scavenging.

To prevent such lead fouling, avgas contains a "lead scavenging agent" called ethylene dibromide, whose job it is to dissolve excess lead and let it pass harmlessly out the exhaust pipe. However, ethylene dibromide doesn't do its scavenging job unless combustion temperatures are fairly high. That's why lead fouling problems tend to emerge when CHTs are below about 300°F.

Click to expand...

That engine is notorious for lead fouling. When I flew behind one, the only solution was aggressive leaning on the ground. Once we made that a routine, lead fouling problems ended for the most part.

Lean!

I'm flying this engine in the Skipper. I clean the plugs at annual (about 125 hours) and I do a lot of ground ops (class C airport). The keys to joy are:

1) When you start - immediately pull mixture all the way back to where it will barely run 1t about 1500. Keep the mixture there or leaner all the time on the ground

2) idle at 1200 if you can. Keeps the heat up and the lead scavenger works.

3) When you do your mag check, go rich, run up to 2000 or so, and lean it out for about 15-20 seconds to burn off any lead. Then go to 1900 or whatever and do your mag check.

4) Immediately after mag check, go back to 1200 idle and super lean. It should be so lean on the ground that you cannot add takeoff power (if you do the engine will sputter).

5) In air, I fly at 2540 rpm (<75% power down low) and lean very aggressivly with an engine monitor. CHTs are in the 300s and EGTs in the 1250 range. Operating very lean I can get a 30-50 degree temp spread between cylinders. The engine seems very smooth and happy.

6) When you land, immedialy go to super lean.

I've used both the fine wire and the longer nose (REM38by?) plugs in the bottom and there isn't a big difference with lead... the key is operating technique.

Good luck!

Kyle Boatright said:

That engine is notorious for lead fouling. When I flew behind one, the only solution was aggressive leaning on the ground. Once we made that a routine, lead fouling problems ended for the most part.

Click to expand...

Agree totally.

I had the 0235 L2C in a LEZ and did not have a problem with fowled plugs. All it takes is very aggressive leaning on the ground (and in flight). On a hot day, I leaned it slightly on take off. Once in climb, ease the throttle back a bit and lean it - had one EGT gage and getting it off the peg seemed just right.

Also, REM37BY plugs helps.

Are you using REM37BY plugs?

Your engine is the one they were specifically developed for... To help with lead fowling problems.

fouling in a 0235 L2C

I flew a 0235 L2C ,Carb in a LongEZ for a number of years. The ground taxi leaning as stated above works. Lean Excessively on taxi until the engine almost shuts down. Also the REMB37XXX massive electode plugs work better. Ran 100LL the entire time. The only trick I found was to clean the lower plugs about every 25 hours. DRR

You do you TCP or Decalin, don't you? If not, do that. Aircraft Spruce has them.

RScott said:

You do you TCP or Decalin, don't you? If not, do that. Aircraft Spruce has them.

Click to expand...

I have the o-235 L2C in my C-152. The TCP was no help at all. I also switched to the REM37BY plugs and that was some help. I mix a little (up to 15-20%) premium auto fuel with my 100LL and it REALLY made a difference. Like I said,,,,the TCP was a waste of $$. My .02

L2C

My Tomahawk with O-235L2C had a propensity for lead fouling as well. The best solution we found was a little leaning on the ground especially on any long taxis and to keep the idle higher not lower. IIRC there are other good reasons for avoiding low idle as well. Also I think the idle carburator setting gives you the richest mixture, all other factors considered.
I am not sure if the "no accelerator pump" had anything to do with it. I think the carb design runs richer than you think; I always had a hard time getting the rpm increase on idle mixture cutoff.
Dave A.

koda2 said:

I always had a hard time getting the rpm increase on idle mixture cutoff.
Dave A.

Click to expand...

Actually that is an indication of a lean idle mixture. If the idle mixture is too rich you will have a large RPM increase as you "lean" the mixture towards idle cut-off.

Yep, +1 for lean on the ground. I lean at cruise too, no matter what the altitude. The other thing that will bite is running low RPMs in flight for extended periods -- either to slow up for someone else or because you want to loaf along. 2350 or higher...

Marvel mystery oil in the fuel will fix this problem... Cleans and lubes the top of the engine too...
Mixing the auto gas in also works...
Also, run the engine hard for at least five or ten minutes per flight. Lower settings seem to foul the plugs quicker...

Lycomings free advice

can be had for the price of a phone call. Ask for "Key Reprints" Have your engine S.N. ready and they will send you this book for free. One piece of advice will be to idle between 1000 and 1200 RPM. There is a time when both intake and exuast valves are open, and this overlap is designed to scavenge out the exaust gasses and draw in more of a fresh charge. Also shut down using idle cuttoff from a higher RPM.
Andrew

lcnmrv8r said:

use Unleaded gas.

Click to expand...

+1!

Cut the 100LL with 50% (or more) car gar, then find a mixture you are comfortable with. I ran 100% car gas in my 0-235 / RV-3.

Geico266 said:

+1!

Cut the 100LL with 50% (or more) car gar, then find a mixture you are comfortable with. I ran 100% car gas in my 0-235 / RV-3.

Click to expand...

There is 4 times as much lead in 100 LL as there was in 80/87, which this engine was designed for.

Unleaded auto gas IS a viable answer if you're Experimental, or can find an STC.

We're running 3 motor gliders with this engine, and suffer from all of the bad habits mentioned above:

Not (insufficient) leaning in ground ops,
Not (insufficient) leaning at altitude,
Low RPM operations at altitude,
Low RPM operations in ground operations,
Operated by PURE glider pilots that can't even spell LEAN,
etc., etc., etc.

REM37BY plugs help, but are not the answer.

While I'm also concerned about the fouling, I absolutely shudder every time I pull the bottom plugs and can HEAR the metallic LEAD residue hitting the bottom cowling

Makes me feel just a little better flying behind these knowing I'm in a glider, less so realizing it has a 60' wing span and my landing out options are minimal in a populated area.