Hard starting-anything I have missed?

[norcal64d]

My MX-7-180 O-360-C1F has been getting harder and harder to start lately. Cold, warm, doesn't seem to matter, today took 15 mins of trying different techniques to get it to finally catch after which it rattled and shook for 30 seconds before running normally. I've read through other hard starting threads and it seems like mags might be the culprit. I checked timing, it was advanced a few degrees but setting it back to 25 degrees didn't seem to help. Primer lines and nozzles are flowing fine. Top spark plugs are look normal (didn't check the gaps though, don't have the right feeler gauge). I didnt pull the bottom ones yet but I don't really think it's a plug issue. The plane runs great with 90 rpm drops on each mag. Anything else to try? The mags are slicks with 750 hours since new in 2011, never had a 500 hour done on them. In my mind this is likely the issue and I'll need to send them off for the 500 hour inspection and service for $400-450 per mag. Anything else to try before this is the last option? I'm debating a SureFly but they also just raised their price to $1400 which is pretty spendy!

[gbarrier]

Overhaul the mags. A good mag check has nothing to do with how well they start. There is a reason for that 500 hour thing. While you're at it add a second impulse coupling and remove the jumper if it is there on the switch where it only starts on the left. You'll love it.

[gdflys]

Have you verified the impulse coupling is actually snapping by hand? Some of the faster starters may spin the engine so fast on start so as to retract the pawls with weak springs on the impulse coupling too.

[norcal64d]

Thanks for the replies so far. The impulse coupling does snap, I couldn't say whether or not it does while the plane is cranking though. This issue started after the plane sat for a month while I was traveling for work. Pre heating weirdly enough seems to help when it first started so I just thought it didn't like cooler weather. I flew it from Colorado to Alabama last month and the warmer weather down here doesn't seem to make a difference. I did notice when I was adjusting the timing on Friday that my timing light was blinking on and off when connected to the left mag with the impulse coupling like there was an issue with the capacitor or coil. It still timed just fine though.

[gdflys]

Had you completely disconnected the P lead or just turned the ignition switch to both? That could indicate a bad ignition switch, p lead grounding, or like you said bad mag parts. You may want to try starting it with the left P lead disconnected to see if it starts better. If so, that could indicate an issue with the P lead or ignition switch grounding out somewhere. Although that would also likely cause issues with the mag dropping out intermittently as well which you don't seem to have.

[norcal64d]

I did remove the P-lead while I was timing the mag to see if that helped and it didn't seem to make a difference. I initially was timing the mags with the ignition switch to both and then ended up removing the P-lead. There isn't any stumbling or any other indications of a problem while the engine is running, just the hard starting.

[gdflys]

Most likely a internal mag issue then.

[norcal64d]

So the $1400 question is try out the electronic ignition and go with a Surefly or spend the $600 or so for a 500 hour plus parts on this one...

[TimB]

yes to the Surefly, installed one on a IO-540-W1A5 R/H mag swap out-starts better, one gal per hr less fuel, more power, checked the old mag with 500 hrs on it E-gap was down to 3 degrees instead of 10 degrees and we had hard starting also. The slick mags need to have the so called 500HR inspection done by 400HRS in my opinion from experience.

[Andy Young]

$600 sounds like a lot for the 500 hour service. Local shop here does them for about $80 labor plus parts. Usually just points, for about another $80 or $90.

$600 sounds closer to an overhaul price, which I think is usually around $800.

[norcal64d]

Kelly Aerospace quoted me 350-375 per mag plus parts that aren't on the usual 500hr list but I've heard their quality is hit or miss. Aircraft Magneto Service is $400-450 per mag plus parts. I'm thinking the impulse coupling mag likely needs parts so I ballparked $600. I haven't seen any local shops that do magnetos down here in Alabama other than Kelly.

[Andy Young]

Based on my personal experience, I’d say run, don’t walk, away from Kelly.

Might be worth shipping them out for a better deal. I could do my own mags, but Greg Boom at Mountain Air at KBJC gives me such a good deal, I bring all my customer’s mags there instead. His price to the general public might be higher, but might be worth give him a call for a quote.

[TxAgfisher]

Andy, do you have contact info for him? I need to do mine this year and thinking if I can avoid shipping all the way to Aircraft Magneto Service I will.

[norcal64d]

Andy, do you have contact info for him? I need to do mine this year and thinking if I can avoid shipping all the way to Aircraft Magneto Service I will.

Found his website, (303) 469-1380.

[LT4247]

after 750 hrs on your mags (assume they are Slicks) i would replace both. I think you will see a big difference. I gave up on 500 hr inspection IRAN because of early failures. But that just me. New mags = piece of mind. Order them up at Spruce, pop them on and send in the cores. Easy and saves lots of time. Cost more, tho.