What Mags are installed and when was last time they were pulled off for a service? They tend not to get their 500hr inspections as they seem to be just forgotten about until some kind of failure. Lately, seems Bendix Mags do better, and the 500hr inspection on the Slicks costs so much, you can almost buy a new set for price of the parts!! And now it appears pricing of Bendix has come down near the Slicks, and I think they're a better mag, and also much cheaper to rebuild. Though I do currently have 1400hr slicks on mine, and they're still sparking away with no problems, but I also do the 500hr inspections.. Also whoever does inspection needs to really look good at impulse coupler. I would also suggest that an accessory shop connected with engine rebuild shop does the inspection as not only do they usually give a better looksee, they also usually have the equipment to spin the mag, checking out operational voltages, etc. Last time mine failed, you could crank engine by hand and get snap, but coupler wasn't working at cranking speeds. Replacement fixed hard starting.

Mags are Slick Aircraft Products. Left is model 4371, right is model 4370. TTAE is 680 hrs and I find no logbook evidence that anything was ever done regarding mags other than check timing. I know nothing has been done for the last 160 hrs.

My slicks where in good shape after 650hr. Just changed capacitor in one and good to go.
I tried changing to Bendix models BL-349365-3 and BL349305-1 on last annual but the left mag won´t fit because of the throttle cable support.
Jim mentioned you might need a field approval or STC for the swap, I don´t think its worth the hassle and extra weight (bendix mags are huge)

Mags can be either Bendix or Slick, so long as proper mag installed nothing but logbook entry required... Of course if you start changing from recommended stuff, that's where you have problems paperwork wise. In any case, only point I was trying to make is that the mags tend to get overlooked for any maintenance so long as they keep working correctly, and that they do, in fact, give problems occasionally...

Just a follow-up and thanks to everyone who replied. Had mags serviced a couple of months ago and the plane starts much easier. 4 primes when cold, starts first attempt!

Just a follow-up and thanks to everyone who replied. Had mags serviced a couple of months ago and the plane starts much easier. 4 primes when cold, starts first attempt!

Our O360 recently took many attempts to start. While cranking, no sputter sounds of partial firing which concerned me.

Biggest concern is after it ‘sort of starts’ it runs terribly rough, like only one or two cylinders is firing.

Could I be flooding the engine, or does this sound like Mags?

Thanks for your comments.
SG

Terribly rough should be very concerning as could be a stuck valve. Does it clear up after ten or so seconds. Does it happen when engine warm? If so could be a condition called morning sickness and better have it checked out as can bend a valve or pushrod.

When my mags needed service, once the engine fired it would run pretty rough for maybe 5-10 seconds. That being said, a sticky valve isn’t anything to mess with!

Paul, not to oversimplify or take anything away from the above inputs. I own a M5-180 (0-360) and my previous 2 RVs and family 8GCBC I towed banners and gliders with for 3K, all shared the same bulletproof Lycosaurus.
My basics are:
Marvel Mystery Oil fuel treatment every 50 hours.(helps alleviate sticky valves and buildup)
Use REM 37BY plugs always (hotter)
Preheat below 32F OAT using closed cowl plugs and a hair dryer pointing between exhaust pipes for 10-20 min.
Get in, Master On.
BP on 3 sec while simultaneously two full pumps of the throttle, then leave cracked (1-1/2 turn on vernier)
Prime two pumps
Clear prop-starter engage.
If mags are healthy and properly timed it should fire immediately. Electronic IGN STC even better. Slick start helps also but I've never needed it.

My Dos Centavos!
V/R
Smokey

Sounds like a magneto problem, stevesMaule180. Have you checked the plugs for fouling? If they look okay, then I'd look next at magneto timing. If that's okay then I'd inspect the magnetos next. After that check the plug wires. If all of them are okay, then how about fuel pressure? Does it start better with the auxiliary electric fuel pump on? Is the gascolator screen clean? Is there any water in the fuel?

I will try a few of the suggestions, and repost in 2-3 weeks.

I don’t think I have a stuck valve (830 ttsn) but I could be wrong. She starts quick in warm weather.
We had the required ‘500hr mag service’/rebuild at around 730 hours.

Thank you to the several reply folks. We read them all.

Does anyone prime when the starter is turning the engine?

Steve, I have never primed while spinning the prop mainly so I can focus on the main thing going on and potential fire feeding. However comma, a friend flew to a safe landing using only pumping the primer feeding the engine after a carb fuel line broke.

One thing you might try is pre heat on cold days. My T Craft was cold natured and 20 min with a closed cowl and a hair dryer did wonders.

V/R
Smokey

Thanks Smokey. I was in south AR in my own hangar so it was easy to to a little preheat, and like you say, it fires up with no issues.

Now we are in Jackson MS in a shared hangar, airport managed, and they do not let us do preheats for ‘insurance liability’ reasons.
I miss having my own hangar space!

I always preheat with a plug in electric heater pad, but even in 10 below weather I give it three shots of primer, crack the throttle, and hit the starter and it’s firing after a blade or so on the prop.

What kind of temps were you seeing with the hard to start issue? I’ve heard it’s possible to “frost” the plugs while cranking in cold weather and then be very difficult to start after.