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Old 02-02-2015, 02:23 PM
CharlieWaffles's Avatar
CharlieWaffles CharlieWaffles is offline
Join Date: Nov 2010
Location: West Linn, Oregon
Posts: 1,360
Default Cold Starts

I know it is usually the hot starts on most RV10s that present challenges, but after a year I have gotten those down pretty dang well. So well, that my cold starts look pathetic next to them.

I haven't found the right mojo yet to get my stock IO-540 (ordered from vans) to kick during the first cranking. I have stock Retard Mags, Slick Start and the stock Vans installed FI - Believe its a Eagle Hawk? I also upgraded to the larger Skytec 142NL starter

All my cold starts involve priming and I have tried using fuel flow as the guide (3-4GPH) before starting, tried fuel pressure, and even just counting. All result in the same thing. Crank for up to 15 seconds. Pause to let starter cool, and then do the same exact thing again and the second time around it kicks by the first or second blade like I expect it to initially.

So I am wondering what COLD start recipes people use for themselves? Perhaps there is a combination I haven't tried yet.
CharlieWaffles - But you can call me "Mark"
Flying - AKA Still Tinkering
Build Project Site
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Old 02-02-2015, 02:53 PM
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Jerry Cochran Jerry Cochran is offline
Join Date: Jan 2005
Location: Sherwood, Oregon
Posts: 981

Hi Mark,

This is essentially what I used on my IO-360 which I believe is the same with your 540.
Jerry Cochran
Sherwood, Oregon

RV-7a 707DD Bot from David Domeier 12/01/11
Lycoming IO-360 Catto 3 blade Panel upgrade in progress

RV6a 18XP 1st flite 03/21/07 sold to Dale Walter 10/22/2011
Superior IO-360, Hartzell Blended, GRT/Dynon

Happily "autopaying" DR

"Suppose you were an idiot, and suppose you were a member of Congress; but I repeat myself."

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Old 02-02-2015, 03:03 PM
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9GT 9GT is offline
Join Date: Jan 2010
Location: Southern Michigan
Posts: 2,270

My cold start method for my IO-540 4VA5:
Throttle cracked 1/4", mixture full rich. Turn on boost pump and after the pump primes and builds pressure (you can hear the change in pump noise), count to 4 or 5 and turn off pump. Don't over prime or it floods. Mine fires by the 2nd blade. I have impulse coupled Slick mag on the left (6351) and non-impulse Slick on the right (6350). No Slick Start.
David C.
Howell, MI
RV-10: #41686 Under Construction/Sold 2021
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Old 02-02-2015, 06:10 PM
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RV10inOz RV10inOz is offline
Join Date: May 2008
Location: Brisbane Qld. Aust.
Posts: 2,308

All the IO360 and 540's will start cold with the following.

1. Throttle WOT and Mixture rich, boost pump on count 1-2-3, pump off.
2. Close throttle and mixture to ICO, crack throttle to a position on your controls that would typically give you 1200 RPM.
3. Crank, as soon as it coughs roll the mixture in, I never see a need to go past half way. Then lean back to RPM rise and slight fall.

For a hot start, do not use boost pump at point 1, although if really hot it may be required after start due to heat soak of the pump.

Next thing to seriously check. Plugs! Gapped right at 0.016-0.018" (or use fine wires) and resistance under 5000 ohms.


David Brown

DYNON Authorised Dealer and Installer

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Old 02-02-2015, 06:28 PM
RV Jerry RV Jerry is offline
Join Date: Jan 2009
Location: Chino, CA
Posts: 202

what I have have done for many years and on many airplanes ,boost pump on full throtle mixture rich count to six, boost pump off retard throttle, miture lean ,crack throttle start ,roll mix In.
same as above post except 3 more seconds ,always starts in one or two blades assuming good ignition
Jerry Scott
Rocket II
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Old 02-02-2015, 06:41 PM
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Mike S Mike S is offline
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Location: Dayton Airpark, NV A34
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Default How I do it.

Full throttle, full rich. Boost 3-4 seconds after the pressure comes up.

Throttle retarded to 1200---1500 RPM apx, leave mixture full.

Crank---------almost immediate start then ease off throttle to high idle and lean as needed for idle position.
Mike Starkey
VAF 909

Rv-10, N210LM.

Flying as of 12/4/2010

Phase 1 done, 2/4/2011

Sold after 240+ wonderful hours of flight.

"Flying the airplane is more important than radioing your plight to a person on the ground incapable of understanding or doing anything about it."
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Old 02-02-2015, 11:11 PM
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bruceh bruceh is offline
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Location: Ramona, CA
Posts: 2,659

I'm having the same cold start issues as Mark on my IO-320. I always end up spinning the engine with the starter at least 2 or 3 times before the engine even offers up a cough or sputter. Priming times have all been varied at times. Priming amounts (throttle position during prime) have all been varied. Maybe I'm not priming enough? I will give it some more priming with the boost pump after the first failed attempt at starting, but I don't want to flood it. I use the Airflow Performance purge valve as directed by their manual to do the priming, instead of moving the mixture (always set full rich). They recommend pushing in the purge valve to RUN for 3-5 seconds with the boost pump on to prime a cold engine. The gauges show good fuel pressure and flow during priming. I've got dual P-mags, so spark shouldn't be an issue. It runs great once it kicks on!
Bruce Hill
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Old 02-03-2015, 01:54 AM
F1R F1R is offline
Join Date: Nov 2010
Location: ____
Posts: 939

IO 540 C4B5. With the same slicks(LH Impulse) as in3 , with a slick start. Tempest plugs. Same as post #3 but I only use a 3 count. That is if it has sat for over 2 days. If I am lucky it just explodes to life instantly. If not quite right it may take 4 or 5 blades.

If I fly one afternoon and start it the next morning I just crank with full rich mixture and bit of throttle open and it fires almost instantly.

Although it is seldom seen any more with glass panels, a standard fuel spider has a port that used to run a pressure line to a flow indicator, often found in the MP instrument.
This was a direct indication of fuel pressure and flow at the spider. It took much of the need to count out of the picture.

Best of luck

Last edited by F1R : 02-03-2015 at 01:56 AM.
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Old 02-03-2015, 05:36 AM
Nukeflyboy Nukeflyboy is offline
Join Date: Aug 2007
Location: Granbury, TX
Posts: 106
Default Cold Start

I have the same setup as you - Vans stock with Slick Start, and my cold starts are very easy. It usually fires on the second or third blade. As you can see from the responses there are a variety of techniques. I crack the throttle, prop full, mixture full and prime for 5 seconds. Mixture off and start, bringing mixture in after it fires.

It seems odd that yours starts so hard. I suspect that you don't have the Slick Start wired properly. Both mags are retard breaker and the manual is not very user friendly. You have to get the jumpers correct on the start switch, too. You can screw these up a bit and the engine will still start, but maybe without the benefit of the Slick Start.

Ask me how I know.
Dave Moore
Granbury, TX
RV-10 and Breezy
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Old 02-03-2015, 05:58 AM
06ktrv6 06ktrv6 is offline
Join Date: Feb 2008
Location: Halifax,VA.
Posts: 27
Default Cold starts

I'm equipped just like you and my IO320 starts on the first blade only with a 15 count initial boost pump prime and then the 3 to 5 count with the purge valve moved to the run position and then back to ICO. Never once any hint of flooding because the purge valve in the ICO position prevents fuel being primed to the throttle body during the 15 count. Give it a try.

Kelly Landrum
IO320 RV6 AFP Lasar
Halifax, Va
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