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IO 360 Hard to Start

I have an RV8A with a Lycoming IO360 A1B, 200hp. It was overhauled a few years back and has 250 hours on it. Attached to the top is a Airflow Performance fuel injector, all moving a MT CS prop.
This thing is just hard to start. Mag timing is spot on.
Hard to start cold and darn near impossible hot.
I’ve asked many and got many answers. Even talked to the Lycoming rep at OSH.
Anyone have the above set up and can offer suggestions?
Yesterday flew, landed and immediately tried to restart hot. Touched nothing. Throttle was at 1000 rpm and mix ICO. Nuthin…
I am hesitant to go places fearing I’m going to get stuck. Always have managed eventually to get it going ,but many attempts in every configuration .
 
I have an RV8A with a Lycoming IO360 A1B, 200hp. It was overhauled a few years back and has 250 hours on it. Attached to the top is a Airflow Performance fuel injector, all moving a MT CS prop.
This thing is just hard to start. Mag timing is spot on.
Hard to start cold and darn near impossible hot.
I’ve asked many and got many answers. Even talked to the Lycoming rep at OSH.
Anyone have the above set up and can offer suggestions?
Yesterday flew, landed and immediately tried to restart hot. Touched nothing. Throttle was at 1000 rpm and mix ICO. Nuthin…
I am hesitant to go places fearing I’m going to get stuck. Always have managed eventually to get it going ,but many attempts in every configuration .

Here's a very good suggestion which I find works very well, and explains a lot. Assuming you don't have a mechanical problem - like bad plugs, bad ignition or something wrong with your injectors, this might help.

https://vansairforce.net/community/showpost.php?p=1181708&postcount=18
 
What shape are the mags and spark plugs? With a healthy ignition system, it really shouldn’t be hard to start hot or cold. I assume single impulse coupling and jumper installed starting on the left mag only?
 
a hot start 10 seconds after shut down is VERY different than a hot start 5-10 minutes after shut down and 30 minutes after is different still. Hot start is all about understanding how much fuel boiled out of the lines, as well as whether or not this displaced fuel has evaporated out of the intake chamber or not, and insuring you refill the lines and get it over rich then start at ICO.

Cold starting is all about the amount of prime shot (required prime shot is dependent upon ambient temps). Suggest you experiment here first and see if you can get a good cold start sequence. If all fail or if you had no issues starting in the past and this is a new symptom, look for ignition problems (failing impulse, high resistance leads, bad plugs, etc.) or intake leaks. Incorrect idle mixture can cause starting challenges as well


Larry
 
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Replace one mag with a Surefly Emag.

Second this ... or whatever electronic ignition you like ... my first summer with a newly built RV-14 was an eye opener after dealing with hot starts in Alabama's humid heat, just trying to airport hop for fun, stopping to see friends along the way ... prompted me to research and install dual electronic ignition. Haven't had any issues since, always starts, hot or cold.
 
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What mags do you have ---- had the same problem

with an overhauled engine. After a very frustrating year of hard/no starts, found out the OH shop had installed a retard mag (no impulse) but did not install a Slickstart.

Just a thought

And, the Surefly suggestion is right on!

Ron
 
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If you have mags, the coil could be getting weak. I had the left Slick in my RV-3 do that. After it was running, mag check was normal. Slowly became more and more difficult to start until it wouldn’t.
My RV-8 has SDS and an implus Slick and starts with both on very well, both hot and cold.
 
Do you have an impulse coupling or a starter vibrator? Do you have a key switch? We had a similar problem with a Lycoming powered Bucker. It was a bear to start, especially warm. Eventually I noticed it would often fire right when I was moving the key from start towards the mags to give the starter a breather. Traced it back to improper wiring in the key switch/mag/vibrator circuit.
 
You need to determine if it is a fuel issue or ignition issue or a technique issue .
Try cranking the engine very carefully with a top and bottom plug out of one cylinder and rehook the ignition leads to the plugs. Make sure the plugs are grounded and observe if you get spark on either sparkplug when cranking. If no spark or very weak spark that is an issue.
If you have impulse mag which a stock io-360-a1b would have, then your left mag should be a bendix 1200 series impulse mag. This is a vey hot mag with a gigantic coil. It should be able to supply a very hot strong spark when just manually pulling the engine through. Carefully determine with the mags switch off and ignition grounded that the left mag impulse clicks with a loud snap at TDC. If the impluse clicks loudly at TDC and you saw a good blue spark at the plugs during the first test, It is unlikely you have an ignition issue. unless you have spark plugs with gigantic gaps. If you prove out the spark issue as being good then make sure that when the engine is cranking with the mixture in idle cutoff that no fuel is going to the flow divider. and that adequate fuel is delivered when the mixture control is advanced from idle cutoff. If you can fully control fuel delivery with the mixture control from none to good flow and you have good spark as measured with the above tests, then your issue may be starting technique. It really sounds as though you have ignition issues to me and I would test that first if it were me.
Good Luck,
Mahlon
 
Hot starts have lots of variables, lets focus on the cold start problem.

Q#1 - What's your technique for cold starts? Be as specific as possible, ex:

Boost pump on for x seconds (or y psi)
Throttle position
Mixture position
Typical "cold" ambient temperature

If one of the mags is a Bendix 1200 with impulse coupler, it ought to start easily.

Q#2 - do you have an engine monitor that records data?
 
IO-360 Starting Article

I was feeling the same way about starting my engine when hot or just getting fuel. This article by Vic Syracuse from Base Leg Aviation helped me and no more starting problems.
 

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