Hard Starting

[MHemperly]

Normal start for me:

Master on

Throttle full

Mixture rich

Boost prime 7 seconds

Mixture back to idle cut off

Throttle pulled back to 1/2 inch open

Crank starter, engine fires one turn every time

Once it fires advance mixture

Set idle 900/1000 rpm

Hot start:

Same exact thing except I only boost prime for 2 seconds and I leave the throttle open and pull the mixture back to idle cut off crank engine. Usually fires 2/4 turns of the prop. But be quick with the throttle and mixture once it does.

This is what works for me and seems to be the least strenuous on the battery and starter. Good luck!

Mike

[Tom]

When does the engine actually bite?  Only as the key is being released off the start detent or midway through blade flip #100 or so? 

[Marauder]

This thread's topic should be changed to "How to get your lady hot". The amount of pumping, throttling and cranking you guys are doing is amazing!

To the OP: You will need to experiment with different starting scenarios, starting with the operator's manual. My operator's manual procedure didn't work and I experimented until I found one that did -- and then I wrote it down. The cold start procedure for me below 40 degrees is different than the cold start at 70. Same with the hot start.

And then when you think you have it figured out, it will occasionally throw a curve at you.

[Bob - S50]

A couple things..

 

Mark.  Your crank speed sounds like ours did with the original starter.  We finally replaced it with the Skytec and it cranks a bit faster now.  Also, I noticed you ran the boost pump 8 seconds.  Might have been too long and flooded the engine.  Try running it for less than 5 seconds.  Our book ('78 J) says to run it "to establish pressure" then off.  That might only be a second or two.

 

N201MKTurbo.  Sounds interesting.  I think I'll try that tomorrow when I go to fly.  Do you do the same thing for a hot start or do you leave the mixture at cutoff until it catches?

 

All.  What difference does the throttle make before you crank?  As far as I know, it only regulates airflow not fuel flow.  During cranking it will make a difference because it will vary the amount of air that is available to mix with the fuel, but I don't understand what difference it will make while we are fiddling with the mixture and pump.  Same thing with the prop.  Shouldn't make a difference until we crank.  I think they just have us put it full forward early so we don't forget to do it during the start.  Full forward will create the least amount of drag on the engine while it is trying to come up to speed.

 

Bob

[Ellioth]

Oddly, I get pleasure when I read others have challenges getting their IO-360A3B6 to start!

 

In July 2013, we had a factory re-manufactured engine installed. As the months wore on, the starting (hot or cold) became more and more challenging. (Note 1: I am understating how bad it really was. Note 2: We have a "modern" geared starter and a fairly new battery.)

 

At the summer 2014 annual inspection it was easy to convince our shop that there was a problem starting the beast. An unnamed engine manufacturer suggested we use the following cold start technique: 

 

(1) Do not turn boost pump on!
(2) Mixture full rich
(3) Throttle about 1/4" open
(4) Crank engine, increasing throttle after a few blades if it doesn't start.

 

Surprisingly, it works for us -- and does to this day, despite what I will write in the few next paragraphs. I should state that the unnamed engine manufacturer also had a different hot start procedure which we also use to this day. The different hot start procedure is:

 

(1) Throttle—FULL FORWARD
(2) Mixture - FULL FORWARD
(3) Wait - Approx. 5 seconds (To let gravity flow purge vapor from fuel lines)
(4) Mixture - IDLE CUT-OFF
(5) Throttle - OPEN (Position throttle for idle at 1,000 rpm)
(6) Ignition Switch - START (Start engine without delay following the previous steps.)
(7) Mixture - Advance slowly until engine starts
(8) Boost Pump - ON momentarily after start, if engine idles roughly to purge remaining vapor from fuel lines. This should be necessary only at high ambient temperatures.

 

After the annual inspection and the implementation of the new procedures all was well -- for about 15 hours of engine time.

 

To keep this post from being of infinite length, the ultimate resolution was replacement of BOTH magnetos. After 150 hours use, they were wearing out and the timing was drifting several degrees per 15 hours of running. Also, the impulse coupling's spark was extremely weak. The unnamed engine manufacturer was very helpful during this phase of the hard starting problem. Very helpful! Very very helpful! 

[Bob_Belville]

My IO360A1A consistently starts much easier after going to fine wire Tempests. And they've never fouled.

[aaronk25]

Boy starting can be a you know what if battery/starter due for replacement, plugs and mags somewhat worn......

Not much fun. Always amazed how much easier it starts with fresh mags.

But remember....all this advise is worthless if the whole issue is not getting enough prime to the cylinders! The best mags, plugs and starters won't light AIR on fire.

Before tearing into it try priming longer. Most of the time if flooded at least one cylinder will cough or slightly fire. If it's just crank in with no sign of life prime it longer! I mean heck all it would take is a sticky spider that distributes the fuel, to take just a bit longer to open and that could be the cause....try seeing what it takes to actually flood the engine.

Every plane is different and I'd be a fool to tell you that 3,5,8 or 10 sec prime is correct for a plane I've never started.

However, I do make a fool of myself from time to time....

[jetdriven]

A couple things..

to

With the throttle full, mixture rich, and electric boost pump on, the fuel flow on my IO-360 is around 7.5 GPH. At idle it's more like 1 GPH. So it does make a difference. I learned this when chasing down an injector problem, we pulled the injectors out and ran the pump quite a bit .

I learned this part from a mechanic at Leesburg, FL. If you always prime it at full throttle you have a known flow rate. 1/2", 1" throttle etc are different and can vary. So since then I prime it just a couple seconds at full throttle.

[aaronk25]

Last idea...next time your at your mechanic (assuming engine hasn't been run that day) have him pull a injector nozzel and time how long you have to run the boost pump to get fuel to start flowing...

[Andy95W]

Last idea...next time your at your mechanic (assuming engine hasn't been run that day) have him pull a injector nozzel and time how long you have to run the boost pump to get fuel to start flowing...

And check the difference between full throttle and idle while you're at it.

[BillC]

Marke ,

You never said if this is a new or old problem. You mentioned a recently overhauled engine. Newly overhauled fuel injection system too?

Bill

[markejackson02]

Got it to fire up right away tonight.  Throttle open 1" (~1000 RPM), prop forward, mixture cutoff.  Boost pump on till 20 lbs, about 4 seconds.  Then off.  Mixture to rich then back to cutoff.  Waited 30 seconds and crank.  Started after about 5 revolutions.

 

Then I noticed that the vacuum pump wasn't working.  Always something....

[Awqward]

I went through some of this when I got my J....it seems they all have their own personalities to a certain extent....for cold starts I found 5-6 seconds of boost WAS NOT ENOUGH.....I switch the pump on for 8 seconds ... Starts straight up now

[aaronk25]

Sounds like you weren't getting fuel before. Good deal.

[markejackson02]

Sounds like you weren't getting fuel before. Good deal.

I think having the throttle in cutoff was also shutting off the fuel.  I was reading a training manual about fuel injection systems and it appears that having the throttle full out can shut off the flow of fuel to the cylinders.

[markejackson02]

Marke ,

You never said if this is a new or old problem. You mentioned a recently overhauled engine. Newly overhauled fuel injection system too?

Bill

Yes, abotu 25 hours on the engine/fuel system.

[markejackson02]

ame="Bob - S50" post="192576" timestamp="1422290106"]A couple things..

to

With the throttle full, mixture rich, and electric boost pump on, the fuel flow on my IO-360 is around 7.5 GPH. At idle it's more like 1 GPH. So it does make a difference. I learned this when chasing down an injector problem, we pulled the injectors out and ran the pump quite a bit .

I learned this part from a mechanic at Leesburg, FL. If you always prime it at full throttle you have a known flow rate. 1/2", 1" throttle etc are different and can vary. So since then I prime it just a couple seconds at full throttle.

That's what I had thought about the throttle.  But it appears there is an idler pin that can cut off the flow of fuel to the injection system when the throttle is fully closed.  It may be an adjustment thing.  But cracking the throttle 1" appears to have solved it.

[ArtVandelay]

I went through some of this when I got my J....it seems they all have their own personalities to a certain extent....for cold starts I found 5-6 seconds of boost WAS NOT ENOUGH.....I switch the pump on for 8 seconds ... Starts straight up now

What were your throttle and mixture positions when running the pump?

[jetdriven]

That's what I had thought about the throttle.  But it appears there is an idler pin that can cut off the flow of fuel to the injection system when the throttle is fully closed.  It may be an adjustment thing.  But cracking the throttle 1" appears to have solved it.

Then how does it idle with the throttle closed? The main jet is cut off but there is an idle circuit.

[Bob - S50]

ame="Bob - S50" post="192576" timestamp="1422290106"]A couple things..

to

With the throttle full, mixture rich, and electric boost pump on, the fuel flow on my IO-360 is around 7.5 GPH. At idle it's more like 1 GPH. So it does make a difference. I learned this when chasing down an injector problem, we pulled the injectors out and ran the pump quite a bit .

I learned this part from a mechanic at Leesburg, FL. If you always prime it at full throttle you have a known flow rate. 1/2", 1" throttle etc are different and can vary. So since then I prime it just a couple seconds at full throttle.

Interesting.

 

Thanks.

 

Bob

[Awqward]

Hi TJ, for priming I have the Mixture full rich and the throttle cracked by 1/2" or so...then Mixture ICO, eave the throttle where it is and crank...

 

Anthony

[cnoe]

Got it to fire up right away tonight.  Throttle open 1" (~1000 RPM), prop forward, mixture cutoff.  Boost pump on till 20 lbs, about 4 seconds.  Then off.  Mixture to rich then back to cutoff.  Waited 30 seconds and crank.  Started after about 5 revolutions.

 

Then I noticed that the vacuum pump wasn't working.  Always something....

 

So that I understand... you are priming the engine with the boost pump "off"? Since fuel is essentially un-compressible it seems to me like you can't be getting very much fuel into the cylinders.

 

I understand that it takes different amounts of prime for different pilots (and engines) with most quoting 2-8 seconds of "boosted" priming. And as suggested you'll need to have the throttle open some as well.

 

I'm in Houston (i.e. warm climate) and I usually fire right up with 2-3 seconds of boosted priming. My technique is to prime, set throttle to idle, mixture to ICO then crank. When it fires (in 3-4 blades) smoothly advance mixture to rich (then back to aggressive lean for ground ops).

 

All the successful methods listed here seem to use priming to some degree except N201MKTurbo's (which is an anomaly that only uses 1 qt. of oil every 40 hours anyway).

[markejackson02]

So that I understand... you are priming the engine with the boost pump "off"? Since fuel is essentially un-compressible it seems to me like you can't be getting very much fuel into the cylinders.

 

I understand that it takes different amounts of prime for different pilots (and engines) with most quoting 2-8 seconds of "boosted" priming. And as suggested you'll need to have the throttle open some as well.

 

I'm in Houston (i.e. warm climate) and I usually fire right up with 2-3 seconds of boosted priming. My technique is to prime, set throttle to idle, mixture to ICO then crank. When it fires (in 3-4 blades) smoothly advance mixture to rich (then back to aggressive lean for ground ops).

 

All the successful methods listed here seem to use priming to some degree except N201MKTurbo's (which is an anomaly that only uses 1 qt. of oil every 40 hours anyway).

 

I got the training manual for the fuel injection system.  It appears that the way I was "priming" with the throttle and the mixture closed wasn't injecting any fuel into the cylinders.  Cracking the throttle releases a needle valve in the fuel metering system that is closed or close to closed when the throttle fully retarded.  Turning the boost pump on with the mixture closed causes the pressure in the fuel line to build up.  Then you open the mixture which injects the fuel into the cylinders.  Mixture to cutoff and crank.  See how it works in the Houston summers.

[ArtVandelay]

So I count about 7 methods, question for the following, how many turns does it take for a normal start?

Kmyfm20s, flyby201, n201mkturbo, awkward, elliotr

[Awqward]

About 2 seconds...so what's that...about 1 or 2 revolutions?