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Old 04-20-2017, 10:07 AM
F1R F1R is offline
Join Date: Nov 2010
Location: ____
Posts: 552

Originally Posted by JamesClarkIV View Post
Haven't run yet but have hopes that this will help.

Does this mean I need to be even more aggressive with the leaning during ground ops?
No doubt it will help. I generally clean my bottom plugs ever time the cowl is off every 35 Hours for an oil change. I use a dental pick only as bead blasting wears the electrodes and insulators.

On the ground, you can lean to max RPM and that is more than 1/2 way to cut off on mine. Taxing around below 1000 RPM is no issue.

With good technique and good understanding of the fuel condition starting is no big deal. However, addition of a Slick start will save cranking and light off fat or lean mixtures with ease.

With a slick start, it will start like a Toyota hot or cold, (if plugs and mags are good.)
It will save the cost of a battery and starter and a lot of headaches.

Last edited by F1R : 04-20-2017 at 10:09 AM.
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Old 04-20-2017, 10:55 AM
Toobuilder's Avatar
Toobuilder Toobuilder is offline
Join Date: Jul 2009
Location: Mojave
Posts: 3,882

Originally Posted by JamesClarkIV View Post
I'm looking for help understanding my hot starting problem....

....I've tried a variety of techniques that I have read about here for starting after a short < 1 hr lunch stop, but I'm convinced it is a weak ignition, not plugs, not mixture, not knobology technique during start...

...I'm quite interested in getting a single EI to replace a mag as I think this may help my starting (#1 goal)...
I believe your troubles are primarily mixture. I'm very confident that if you perform the clear engine procedure on every hot start you will be much better off, regardless of ignition. As a data point, my Rocket started fine with no impulse, and no Slick start - just regular old mags.

However, to your question about EI - yes, it will help your starting process. It would be a tough sell to justify it as a starting aid only, but that's for you to decide. If you are buying it as a starting aid only and have no interest in chasing down LOP optimization, then I'd look hard at an ignition that can be programmed to have a flat (or zero) advance curve. In other words, one that provides a strong spark at start, a healthy retard function for no kickback, and the ability to otherwise emulate the magneto timing that you are comfortable with. If you decide to go this way, take a good look at CPI, as it can do that as well as being optimized for cruise should your mission call for that in the future.
WARNING! Incorrect design and/or fabrication of aircraft and/or components may result in injury or death. Information presented in this post is based on my own experience - Reader has sole responsibility for determining accuracy or suitability for use.

Michael Robinson
Harmon Rocket II -SDS EFI instalation in work
RV-8 - Flying
1940 Taylorcraft BL-65 -flying

Last edited by Toobuilder : 04-21-2017 at 11:35 AM.
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Old 04-21-2017, 10:09 AM
mcgaughy mcgaughy is offline
Join Date: Mar 2009
Location: Fayetteville, NC
Posts: 24

My guess is that the majority of the hot start issue is fuel injection related.

Wouldn't hurt nor cost all that much to have a knowledgeable mechanic go through your mags. With that little time, there shouldn't be many parts needing replacement. I had a mechanic work on a mag once and didn't fully tighten the points adjustment engine suddenly started missing and running alike a 3 legged dog on final.... My point here is that gross miss timing internally can cause significant issues. By the way, my experience has been a slight timing advance when breaking in new mags. Maybe a degree or so. I believe the "book tolerance" is +/- 2 degrees? If that is so, then it could have came from the factory set at +2 and you had a little wear afterwards. No way to really know without having the Mags IRAN. Just don't get frustrated if all the mag work doesn't completely solve the hot start.
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Old 04-22-2017, 02:03 AM
WAustin WAustin is offline
Join Date: Jun 2011
Location: Denmark
Posts: 12

Mine did exactly the same as you describe. Left impulse mag was outside the recall range of serial numbers too, but still had the internal wear, or so I believe. It was only just outside the range by the way. Pulled mag off and apart and all items tested ok. I had details from my LAME in Australia. Replaced the mag as that was the most recommended idea on Vans and the internet I could find after several months searching. Also replaced all 8 champion plugs with Tempest. Plugs had a wide range of resistances with some well over 5000 ohms. I used to worry about hot starts away from home base, but now no longer do. In fact I think a true hot start, say after landing, refuelling and then taking off sees a better start than when cold. Start procedure is master on, flaps up, mixture cracked up to 1/4 in, key to start and add mixture til it fires. Works every time now. For me, the cost of replacing the mag has given me a massive peace of mind I never had before. This was after 18 months of going to flyins and having all sorts of help from other M1B owners, tech councillors etc. Other owners could never understand my problems as theirs started using the procedure I described.

Good luck with getting a resolution. Perhaps if you could "borrow" a left impulse mag you might solve your problem. An impulse mag was way cheaper than the equivalent EI mag for my purpose.
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Old 04-22-2017, 05:59 AM
David-aviator David-aviator is offline
Join Date: Feb 2005
Location: Chesterfield, Missouri
Posts: 4,467

In the beginning, I had difficulty getting consistent quick engine start hot or cold.

But over time learned the key is proper amount of fuel available, not too little, not too much. The envelope is not large.

Today the engine starts cold on first or second blade all the time using impulse mag only. (I stopped using EI for start because if rpm dropped off immediately after start, it would kick back.)

On hot start it is more difficult because you don't know just how hot it is. But same applies, if correct amount of fuel is available it will start right off. It is very easy to flood when hot.

I do not suggest a technique regarding prime and having just the right amount of fuel available. It depends on Fi system and internal temp of engine. It is a matter of discovery with each engine. If one method does not produce desired result, adjust it. The engine will pop right off if it is primed just right.

I say all this believing the problem is fuel related, not ignition.

I have mag connected to top plugs, that helps.
David Domeier
RV-12 Build Helper
RV-7A...Sold #70374
The RV-8...Sold #83261

I'm in, dues paid 2018 This place is worth it!
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Old 06-21-2017, 07:19 PM
Dan B Dan B is offline
Join Date: Mar 2006
Location: Edmond, OK
Posts: 157

My IO-320 engine started like a champ cold or hot until about a month ago. Then, when trying to start cold or hot, it was difficult or would not start. Magneto had 300 hours since new. Short story is; took the left magneto (one with impulse coupling for starting) to a reputable shop in Tulsa for a check up. On the test bench, the magneto fired ok when it was cold, however after heat soaking it, the coil started failing. It was overhauled while I waited. Starting problem now resolved.
David, Steve, and John at Quality Aircraft Services in Tulsa provided excellent diagnosis and customer service on this problem.
Dan Burdette
Skyview, ADS-B, Garmin 420W, TT Gemini AP
RV-9A, IO-320
Guthrie-Edmond Rgnl, OK (KGOK)
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