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IO-360 HARD TO START

flybywire

Member
I have a Titan IO-375 (360 with high compression pistons) on my RV-7 with 155 hours on a new engine. About 15 hours ago, I started experiencing start problems. Cold start technique: throttle cracked, Mix rich, boost pump on for 3 seconds, Mix cut off, engage starter, advance Mix slowly. Now it just takes several attempts before it finally starts, usually resulting in a flooded engine after so many attempts. Hot starts are difficult but NOW cold starts are more troublesome. Do you think my coupler went bad at 155 hours on the mags? Mag checks on runup are fine.
 
My impulse Slick did the same. Rebuild fixed problem. Mag generates weak spark at low rpm trying to start but runs ok at higher rpm. Mag check at 1800 looked fine. It will get worse and soon leave you stranded if you continue.
 
Maybe try with a bit more throttle. Lycoming Operators Manual starting procedure suggests you "Open throttle approximately 1/4 travel". Seems excessive as I was taught to open it 1/4" to 1/2", but maybe 1/4 travel will reduce flooding?
 
I have a Titan IO-375 (360 with high compression pistons) on my RV-7 with 155 hours on a new engine. About 15 hours ago, I started experiencing start problems. Cold start technique: throttle cracked, Mix rich, boost pump on for 3 seconds, Mix cut off, engage starter, advance Mix slowly. Now it just takes several attempts before it finally starts, usually resulting in a flooded engine after so many attempts. Hot starts are difficult but NOW cold starts are more troublesome. Do you think my coupler went bad at 155 hours on the mags? Mag checks on runup are fine.

I would never try to start a cold engine with the mixture at ICO. Your creating way more work for yourself. That is for hot starts only, where the fuel boiled off after shut down and left an overly rich mixture sitting in the intake plenum (that will be gone in an hour or so of sitting). The key is to learn the length of boost pump activation required for the conditions. In summer, the fuel boils out of the inj lines after shutdown and needs to be replenished before next start (if it is several hours later). This often doesn't happen with cooler ambients. You also need some primer shot via the boost pump. Warm temps require less prime (turning the boost pump on before start) and cooler temps require more. etc...

For my engine when cold, I hit about 2-3 seconds of boost in the summer and 4-6+ in the winter, depending upon ambients. If it doesn't kick over, I add another 1 - 2 seconds and try again. Each engine will be a bit different and require experimentation. Better to be on the short side and add another second or two of boost pump if it doesn't kick over. Much more work when over doing it and flooding.

always wait a few seconds after the boost shot to let the gas evaporate and mix with the air.
 
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Here's what works on my Titan IO-370 with AFP FM200A injector:

Mixture: Full
Throttle: 1/2"
Fuel Pump: On until fuel pressure stabilizes (usually takes about 5 seconds)
Fuel Pump: Off
Mixture: ICO
Starter: Engage
Mixture: Full Rich when engine starts

Of all of the techniques I've used, this does the best job of getting a smooth, strong start without the engine quitting. This is what I use when the engine is cold.
 
Yup

Yes, what Wilddog said. If fuel is getting in and it doesn’t start, ignition is the first suspect. We fixed our O-320 by replacing the Slick mag with a Lightspeed Plasma III. We now have immediate starts, all the time.
 
Started having hard starts hot and cold. The left Slick mag started going bad with only about 200 hours on it. Turned out that the coil was going bad. Had the mag overhauled and replaced the right mag with an E-Mag. Starts like a champ now.

All it takes is a continuous feeding of $$$$ and the little airplane runs like a top! :)
 
Never started a cold Lycoming in ICO.

Hot, yes.

Prime it on the fuel pump, set 1/4" throttle and crank - bingo !

But keep cranking - don't let go on the first sign of firing or else you may get a kick back.
 
GREAT replies guys to my hard to start IO-375 (Especially from "Dan B" lol...)
Since this problem is recent, I'm suspecting a bad impulse coupler. Is this coupler on the left mag? Should I send BOTH mags in as long as I'm sending something back for inspection?

Also, just had a Showplanes.com oil cooler mod installed. I upgraded my 7 row cooler to a 13 row cooler on Brian's (showplanes owner) recommendation. Had it professionally installed only to find Brian shipped me a 10 row air duct instead of 13 row duct :(( I JUST HATE IT WHEN THAT HAPPENS!! Gonna call him to see what he will do for me after that unfortunate mistake. Please see my Showplanes thread on a previous post in the "RV7-7A category. I will update that later today with pics.

Scott D
Santa Barbara
 
IO-360 Start

I ALWAYS start my IO-360A1B6 (Precision Airmotive RSA-5 injection) at ICO. I have had very good luck starting this engine hot or cold. For a cold start, I prime it with full throttle and full mixture for ~ 2 seconds, then pull the throttle to just slightly cracked and the mixture to ICO. It's really no big deal to gently move the mixture forward when the engine catches. I basically follow the same starting checklist that was used in a flight-school Super Decathlon that I learned aerobatics in. I also found that the engine likes to be primed longer in cold weather than in warm weather. Using the ICO starting method help to ensure that the engine doesn't become flooded if it's over-primed initially.

Regarding the onset of starting issues, the ignition advice is good. Check the mag timing. Breaker point wear and/or e-gap (point timing) drift can also have a large impact on starting performance. Also check for bad spark plug leads and bad plugs.

Recently I went through an issue where my engine started mostly normally cold but was almost impossible to start hot (in 10 years, I previously never experienced hot-start difficulty which includes quite a few hot-starts in 100 degree weather). After going through the ignition system and fuel system thoroughly I finally traced the issue to an intake leak. Oddly, I did not notice any mixture distribution anomalies when the engine was running. I replaced a couple of suspect intake to cylinder head gaskets and seemed to get some relief from the problem for a few weeks, then it came back. I then discovered that somehow one of the intake tube to plenum O-Rings rolled or pinched and one segment of it was partially pulled into the sump and pinched on the edge of the C-Groove. Replacing that (and the head gasket again) fixed all of the starring problems.

Skylor
 
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GREAT replies guys to my hard to start IO-375 (Especially from "Dan B" lol...)
Since this problem is recent, I'm suspecting a bad impulse coupler. Is this coupler on the left mag? Should I send BOTH mags in as long as I'm sending something back for inspection?

Left mag usually has the impulse. It will have a spacer between it and the engine. If rt mag was ok on mag check and also has low hours, I would not send it in. At 500hrs mags need inspection/repair.
 
Impuls Coupling

GREAT replies guys to my hard to start IO-375 (Especially from "Dan B" lol...)
Since this problem is recent, I'm suspecting a bad impulse coupler. Is this coupler on the left mag? Should I send BOTH mags in as long as I'm sending something back for inspection?

Left mag usually has the impulse. It will have a spacer between it and the engine. If rt mag was ok on mag check and also has low hours, I would not send it in. At 500hrs mags need inspection/repair.

I'm going to add that if you suspect a bad impulse coupling, you should really learn to inspect it yourself. They are really simple and the Slick overhaul manual provides instructions for inspection. The failure mode of an impulse coupling is usually catastrophic...and they work until they don't. The Slick inspection helps detect the signs of wear so that they can be replaced before they fail. About the only way that an impulse coupling would behave normally on a running engine but not work properly during startup is if the the pawls are either stuck or broken off or the mag case stop pin is missing. Both are obvious on inspection and also why regular inspection of the pawl rivets is critical. If the impulse spring breaks, the mag will operate with retarded timing in this will be immediately obvious during a mag check...unless someone re-timed the mag with a broken impulse spring. Of course a mag with a broken impulse spring is also obvious by the lack of the audible "click" when hand rotating the prop.

Skylor
 
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I sent my mags out for inspection. Just got the word - - bad internal timing more than 20* off ! Tech said they were not calibrated properly most likely from the factory since they only have 155 hours on these SLICK mags. Impulse coupler tested fine. I'm hoping my start problems are history. Gonna slap these bad boys on this weekend and go flying!
 
Flight test complete! She starts like a champ! These mags were brand new out of the factory with very low time and they were way out of tolerance. The only way I found this out was after start difficulty and then sent the mags in for inspection. Lesson learned… Don’t trust brand new slick mags! THANK YOU A/C Electrical Components, Redding CA for your expert work!
 
Interesting to read some start mix full rich with an injected Lycoming. 40 years driving planes for me I always start in ICO cold or hot as per the book!
 
COLD START UPDATE

I have a Titan IO-375 (360 with high compression pistons) on my RV-7 with 155 hours on a new engine. About 15 hours ago, I started experiencing start problems. Cold start technique: throttle cracked, Mix rich, boost pump on for 3 seconds, Mix cut off, engage starter, advance Mix slowly. Now it just takes several attempts before it finally starts, usually resulting in a flooded engine after so many attempts. Hot starts are difficult but NOW cold starts are more troublesome. Do you think my coupler went bad at 155 hours on the mags? Mag checks on runup are fine.

My LYC IO-375 simply will not COLD start using the Lycoming book procedure of starting with mixture rich, throttle open and using the elect boost pump for 2 seconds to prime, then throttle cracked and crank — she floods every time doing that, then I risk running my battery dead. Instead I crack the throttle mixture full Rich and crank the engine and she starts on the 5th blade. No electric boost pump! Thank you
 
Great to find the way your engine starts since not all Lycoming engines need the exact same procedure. I remember years back when going through the learning curve to start my engine it was a great relief to finally discover easiest way to start mine hot and cold.
Your work is not complete as it requires continuous learning and tweaking as the start procedure can change over time with wear on mags, older plugs, longer time since cleaned plugs, OAT, etc. the best way, in my opinion, to have consistent starts is to replace one or both mags with EI.
 
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