O200A no start

[8261]

Hello,

Any suggestions welcome as I’m on my own with no a/p...and yes, I understand this is a/p territory.

1650 hr O200A that will not start. I got back from flying about 15 hrs last week on a remote hunt (8 hrs the day before the no start). Only indication was 4 hrs prior it took 40 blades to start when it is usually a 1 or 2 blade starter. I always hand prop with no starter. Have not had any issues in flight.

My Slick 4301 mags had about 850 hrs since being touched. Yes, I immediately pulled them and had them overhauled yesterday since it was on the to-do list and then this.

Reinstall today, timed to 28 btdc with disc, nothing...

It’s hot here in AK (70 deg). I did not prime and when I was pulling blades thru, I had fuel dripping thru airbox. No way it could’ve been flooded by me and seems very wrong...Stuck valve?

Maybe I just suck at timing?

Any thoughts appreciated. Thanks! Painful to be grounded with terrific alaska weather

Chris

[6643]

I had fuel dripping thru airbox. No way it could’ve been flooded by me and seems very wrong...Stuck valve?

Well, assuming the mags are good and properly installed and timed, it sounds like you've got carburetor problems. By "stuck valve" do you mean the float valve? It doesn't sound like an intake or exhaust valve problem. Last time it started, did it blow black smoke, or did it act like it finally got some fuel?

Too far away to say much more.

[6298]

If it usually starts on the second blade, and you pull it thru several more times, the carburetor will drip. Maybe it is timed to the wrong cylinder and fires on a cylinder without compression.

[8261]

Thanks for the responses. I re-installed re-built mags today and made certain they were timed at 24 BTDC of compression stroke on 1st cylinder. Confident in mags/timing.

I pulled the air box and carburetor for cleaning. Also disconnected the priming line that goes to the intake throat. BOOM! Downstream of the ferrule nut there is a break in the line.

Without being able to solve the problem right now, I believe a lack of priming fuel is getting to the cylinders for start-up and instead going direct to the airbox.

Flies great, never a problem. All regular fuel sources are great. Just the past month, start-up has been noticeably different and sometimes almost impossible.

I'll let you know if a new priming line resolves the issue. Thanks again.

Chris

[8261]

And yes, John...has acted starved for fuel when it did start with some puffs of smoke...

[6643]

The puffs of (black) smoke would indicate it was flooded, not starved of fuel.

[8261]

Yes, absolutely. At the point it started it had been flooded...I'll attempt to give a more detailed idea of what happened and what I have done so far...

I have owned and flown the plane 415 hours. The first 385 hrs were uneventful with no maintenance required besides oil changes at 25 hr intervals, to include oil screen cleaning, and spark plug cleaning/gapping.

At this point the engine SMOH is about 1600. Mags not touched for near 800 hrs. Carb not touched for about 600 hrs (overhauled MA-SPA3 in 2011). Idles great, flies great.

Normally a 1-2 blade starter no matter what engine temp or time of year. Fly all year in Alaska. Engine is always preheated in winter with either the Reiff if near electrical or Northern Companion in the field.

Mag drops have progressively decreased for each mag (still not quite 150rpm drop per mag & about 50rpm difference between the 2).

At about 385 Hrs, the starting became noticeably different. While cold--maybe a 3-5 blade. While hot--10ish. Nothing really concerning, but noted.

September 9th -- Flying loads back & forth for 4.5 hrs. 2 shutdowns occurred for dropping off/picking up and fuel. After the last drop-off and fuel stop (approx. 30 minutes), I do a warm engine start-up (no prime). 20 blades...hmmm. Maybe I need one shot of prime? Done. After 3 more blades I notice fuel dripping out air box. Damn--flooded. Mags off, Throttle--Full Open, Mix--Idle Cutoff, Pull blades reverse 10x. Back to start with it finally coming alive maybe 10 blades later. Fly another 2 hrs, fuel stop, start up no problem. Fly home another 2 hrs. About 8.5 hrs flying this day. Airplane shutdown for next 3 days, OAT's between 45-70 degrees.

September 12 -- Go to fly. Spin the blades for startup...nothing. Blades will spin continuously with no sounds or resistance from the impulse couplers. Crap, mags finally went out...take mags to shop for overhaul.

September 15th -- Get mags back. Re-install mags and install 8 new REM40E spark plugs, time engine, go to start-up...blades have normal resistance and impulse couplers are clicking like normal. No spark, no start.

Now here's the process I used to install and time these Slick 4301 magnetos (pertinent steps only)

1. Lift tail and put in level cruise flight.
2. All 4 top plugs removed.
3. Rotate prop normal rotation until pressure blows thumb off #1 plug hole.
4. Install E-25 tools (#1 cylinder insert and timing dial on skull cap)
5. Continue normal rotation until cylinder lightly touches #1 insert. Rotate dial to TC (tapping dial to ensure accuracy)
6. Rotate prop reverse until #1 cylinder again contacts the plug.
7. Note the # on dial, divide by 2, place dial at halfway point between TC and #. (For instance, I got 96 so I rotated dial to 48)
8. Remove #1 cyl insert, Rotate prop normal direction until thumb blown off plug hole.
9. Rotate prop to about 35 deg BTDC, then slowly rotate normal rotation to 24 BTDC to remove any backlash.
10. ENGINE READY FOR MAG INSTALL.
11. Rotation is "L" for both mags and they both have impulse couplings.
12. Insert T111 pin in the "L" hole on both mags. Rotate drive gear counterclockwise (looking from rear) until pin is shouldered. Tape pin in place to prevent becoming unseated.
13. Install Mag in engine, finger tighten both screws, remove pin.
14. Rotate prop normal direction past TC to un-couple impulses from both mags. Place it back on 24 BTDC and remove backlash.
15. Hook up buzz box--black to engine/airframe ground, Red to left mag, Green to right mag.
16. Rotate mags until lights extinguish and alarm buzzes (indicating point are just opening), tighten bolts.
17. Rotate prop reverse to about 35 BTDC. Slowly bump it normal rotation until buzz box indicates mags are just opening.
18. Inspect dial and confirm the point opening occurred exactly at 24 BTDC. Checks out.
19. Re-install plugs, leads, HT backing plate, and mag ground/p-leads. Ready engine for normal start-up.
20. Start-up...Good prop resistance, impulse couplings audible...no spark...no start. Crap.
21. Remove P-leads to take ignition switch out of equation. Attempt start-up...nothing. Double crap.

Dumbfounded. If you made it through this entirely long-winded post, I'd appreciate your suggestions on my procedure and where I'm failing.

Besides ignition/timing, here's what I've checked:

Fuel: blew out fuel caps, checked fuel flow at carb inlet, checked carb fuel screen, capped and removed primer line from system at intake spider.

Compression: No official #'s, but placed thumb over all holes and thumb was blown off during all compression strokes--assume good and recent annual had good numbers.

Spark: Mags overhauled, externally timed to engine. Any possibility during overhaul that the internal E-gap was not set correct or impulse couplings bad?

Thank you,
Chris

[6298]

It all seems right. My final check, before putting the top plugs back in, is to see if the spark is occurring at the right time. Thumb in number one spark plug hole to feel compression. Before the impulse coupling clicks I hold the #1 spark lead about an 1/8 inch from the cylinder fin and continue prop rotation until I see a spark. The impulse should fire at about the 7 o'clock position. Next blade #3, Next blade #2, Next Blade #4. Next the lower plug wires
I don't usually bother with the pin. With the #1 wire 1/8 inch away from the mag I rotate and the coupling goes off. When the wire sparks it is on #1. Back up a little and you will feel the magnets stop the rotation. This is near the point opening position. Put the mags on and time to 24 degrees in your case.
My 2 cents.

[6643]

What do you mean when you say "blades have no (or normal) resistance"? It sounds like you're saying the engine has no compression. If so, this is unrelated to the carburetor or ignition.

You also said "Mag drops have progressively decreased for each mag (still not quite 150rpm drop per mag & about 50rpm difference between the 2)." If you are down to 150 you were out of spec to start. 150 is about the max you want to see, as is the 50 RPM difference.

Assuming you have good compression (you just got done confirming that, right?) and, since it ran, albeit not well, before you took the mags off, I'd bet the mags are not timed correctly.

If you got this far, I'd do the following:

First, forget the timing gauge for the moment.
Second, be certain you're really on cylinder #1. (right rear).
Pull all the top plugs out. Rotate the crank until you get compression on #1. Stick your pinky, or a wooden stick, in the plug hole and get to TDC. Observe the timing marks on the crank flange. They should align with the bottom split on the case. Turn back past 24 then forward to 24.
When you insert the pin in the mag, rotate the mag backwards to align the holes. If you go forward, you have to go past the point where the impulse coupling trips then back to align the holes. (Could this be the problem?)
Insert the mag and fasten loosely. (Remove timing pin!!!)
Now you can whip out the buzz box and the flower pot if you want and fine tune the timing, just be sure the impulse couplings have been "snapped out" before you try to time it. Don't back up too far or you will reset the impulse coupling which will throw the timing off.

The more I think about it, the more I think your initial problem was the mags, or plugs, or both, and now you've just not got them firing at the right time.

If you want to do a gross check, pull the top plugs out. Get the crank to the point where you're coming up on the compression stroke on #1. Hold the #1 plug wire near the cylinder fins, but not near the plug hole. Switch the top (right) mag on and rotate the prop through TDC. The impulse coupling should fire at about TDC and a spark should jump from the wire. Just be careful as you can light off any vapors that might be floating around.

Repeat for the lower plug wire.

[8261]

Thank you, Randy & John! I’ll give it a shot