Cessna 182P Engine Cold Start Now Different

Sinistar

Sinistar

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Brad
This is for cold starts only: Normally we use 6 shots of primer, mixture rich, throttle in about 1/2" turn to start and in about 1..2 seconds it fires off and runs normally. On the last three cold starts it didn't start like that so I let it crank about 4 seconds and just stopped as it now seems different. I gave it two more shots of primer and it immediately starts (1 second or less). So something has changed and I am wondering what? Any ideas? Maybe no big deal?

We did one oil change about 6hrs back but the cold start was still normal afterwards. We had the lower cowling off/on to install the new landing lights but that was after the cold starts changed and it still remained the same. There has been no other maintenance or changes made during this time. I thought maybe it had to do with the warm/humid wx (in the 90's) but the flight last night it was in the mid 70's and way less humid. I have been working on landings so maybe something got knocked around :)

I always have at least 45...70 gallons total spread equally in both tanks. No apparent fuel leaking anywere (got a very good look when the lower cowling was off). The right mag drops 125 on the run-up and the left drops about 100. Oil pressure comes up over 50psi within a second or two. It idles just the same, still has all the same power during takeoff and cruise. Hot starts are still the same as before, starts right away with 2 shots of primer and mixture lean until it starts.

I was wondering about either the primer may not drawing the same amout of fuel? Or maybe a impulse coupling(?) is broken or not working? Maybe an early sign of a starter or battery problem?
 
Stewartb said:
OAT? I use several prime shots in winter temps and none in summer temps.
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My question too... for 55WB, at most during the summer, two shots of primer, 1/2" of throttle, and it starts on 3rd or 4th blade.
 
When you guys shutdown do you pull the mixture until it stops or just turn off the key and leave gas in it?

We have been pulling the mixture until it shuts down and when it has completely stopped I turn the key to off. So I figure there is no gas in there and thus the need for the primer (summer or winter). When we first got the plane we tried 4 shots and eventually found that 6 (during summer) was the quickest start. We have only started it in the winter after pre-heating and the same primer shots work then too.

Okay, tonite I will go the other direction and try just 2 shots of primer when cold.

Maybe after that oil change something is different? Our 0-470 seems to love 9.5qts and will stay there for hours (ie needs a quart every 10-12hrs or so). When I changed the oil I put in 11qts so maybe that extra oil is getting to the lower plugs?
 
6 during summer sounds like a lot.
 
Check your primer lines. It's very common for them to crack and then you end up priming your cowling which isn't too helpful during starts.

Crack usually gets worse with time - always needing to prime more and more until one day you can't get the damn thing to start at all and finally investigate the problem.
 
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GeorgeC said:
6 during summer sounds like a lot.
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That was my thought as well...I give three good pumps on my 182P and it fires right up every time but I don't have very much climate extremes year round.

Pull mixture for shutdown then master and key off.
 
jesse said:
Check your primer lines. It's very common for them to crack and then you end up priming your cowling which isn't too helpful during starts.

Crack usually gets worse with time - always needing to prime more and more until one day you can't get the damn thing to start at all and finally investigate the problem.
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Agreed. There could be an O-ring bad in there also, which might be causing you to not get the "suck" when priming, hence no fuel stains in cowling. Make sure you are giving it about 2 seconds after pulling the primer each time to fill up before pushing it back in.
On 182J, I use 2 shots primer and 1/2" throttle, usually fires right up.
 
Almost all the Cessna's I have flown rarely if ever need more than 3 shot of primer unless it is well below freezing and not preheated. Now Pipers with the short primer (1/2 the size of the Cessna Primers) usually like 6 shots.
Any chance you have the short primer that only comes out about 2 inches. A Cessna primer usually comes about 3 or 4 inches.

Brian
 
Definitely weird to need much prime at all in summer. Never need more than two solid full shots in winter as long as it's pre-heated. We try not to do non-heated starts in winter so probably take one more if we did.
 
Scrubbed the flight last night due to crosswinds. So my next flight is Thursday evening. I'll get back to everyone afterwards.

I think I just might be going way too fast! I usually pull it out and then push it right back in :) I think I need to slow down, tease her a bit and give her what she really needs!!!

Actually there was a bad primer o-ring that was fixed on the last annual. So it could be an issue again I guess.

I didn't see any signs of fuel anywhere when I had the cowling off on Saturday.

I've only ever flown in this 182 however the primer seems to be...should I say quite "adequate" in length and definitely longer than 2" :)
 
If your primer is picking up fuel correctly you should pull it out slowly and you should hear it pulling fuel. When full it'll offer resistance when pushing back in. If it's sucking air it won't have that resistance.

Remember, warm temps make richer combustion. Less prime should be required. Lean aggressively while taxiing prior to shut down.
 
Stewartb said:
If your primer is picking up fuel correctly you should pull it out slowly and you should hear it pulling fuel. When full it'll offer resistance when pushing back in. If it's sucking air it won't have that resistance.

Remember, warm temps make richer combustion. Less prime should be required. Lean aggressively while taxiing prior to shut down.
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This. It needs a couple of seconds to fill. You can hear it filling.
 
Sinistar said:
I think I just might be going way too fast! I usually pull it out and then push it right back in :) I think I need to slow down, tease her a bit and give her what she really needs!!!
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That's a problem right there. Think of it more like filling up a syringe then slowly pumping the syringe in. I am more of a tree second pull, hold a second for the suction to catch up then a two to three second push for three pumps
 
Shawn said:
That's a problem right there. Think of it more like filling up a syringe then slowly pumping the syringe in. I am more of a tree second pull, hold a second for the suction to catch up then a two to three second push for three pumps
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Exactly. The lines are tiny, as are the inlet and its check valve in the primer, and it takes time for the primer to fill.

Another common problem is a clogged primer nozzle. Fuel in them evaporates after the engine starts and gets hot, and a little residue is left. It accumulates over time and the nozzle will either just squirt fuel in a stream instead of atomizing it in a fine spray, or it will clog solid and not deliver anything. The engine will have either one nozzle in each induction elbow, or a nozzle in each cylinder head. The head nozzles get real hot and clog sooner. They're really hard to clean, and new nozzles will usually make starting much, much easier.
 
Holy crap and I learning a lot from you guys!!!

So last night I slowed things down...but maybe not enough. I took my time to slowly draw out the 1st primer shot and it seemed to have good resistance against my pull. When I pushed shot #1 back either I did it too quickly or there is just less resistance. On the second pull it drew out a lot easier so either I pulled it too fast or it just wasn't drawing as much gas. The second shot pushed back in even easier than the first.

So I thought I'd give it try. Engine cold (48hrs), no fuel as the previous shutdown was mixture lean shutdown. I let it crank about 2 seconds or maybe what seems like about 2-3 full revolutions. No joy.

I added two more shots but both had less overall resistance. Turned the key and it started almost immediately with at most a full revolution. After that it was too warm to dabble any more since I did a flight lesson.

Next time I start it cold I will take even more time on each primer to shot to see if I can get it fill up more.

It just seems weird to me, as if it is getting enough gas but it is now not firing off until a second attempt. That is why I asked about the impulse coupling/spring/thingy or maybe started isn't turning as fast or something.

Also, on times where we taxi back to the FBO and then chat and then I hot start it 20min later I have always given it two primer shots, throttle out slightly and mixture lean and it kicks off within a second. The shutdown just before that was also a mixture lean cutoff to engine stop followed by key off so no fuel in that case either.
 
Maybe you need someone who's flown anything with a primer to try yours and see if it's operating correctly since you don't have anything to compare to.

That or grab someone and see if they'll let you prime a different Cessna that's known working, just so you can feel what it is supposed to feel like.

Usually there's little resistance at all when pulling it out. It's not like a syringe as some have stated in that it doesn't move the fluid during the rearward stroke. It creates a vacuum and you wait a second or two for it to fill, which you can both feel and hear as it does it usually.

When you push, it then does feel like a syringe, full of fluid, moving slowly in.

The first attempt at start not working and the weird primer behavior you're describing sounds like the primer didn't work at all. You're just moving air and not fuel. By the second attempt you've cranked enough to pump fuel through the carb so the engine starts. Easier warm starting without the primer also sounds normal for an O-470. Not for the fuel injected 182s.

That's my guess anyway.

Have someone else try the primer and see if it's actually working. It should be really obvious to anyone who's flown multiple Cessnas.
 
I will definitely either try another or have someone try mine. My instructor is pretty savy on 182's but the last few times I've picked him up so he wasn't there at cold start. Also, I believe their Skyhawk is not fuel injected so I'll ask if they'll let try that one for comparison.

Also, thanks for the clarification. I was reading into it that the outward pull was literally drawing fluid just exactly like a syringe. I need to get nice a quiet and listen for it better, not just go by the force.
 
Sinistar said:
I will definitely either try another or have someone try mine. My instructor is pretty savy on 182's but the last few times I've picked him up so he wasn't there at cold start. Also, I believe their Skyhawk is not fuel injected so I'll ask if they'll let try that one for comparison.

Also, thanks for the clarification. I was reading into it that the outward pull was literally drawing fluid just exactly like a syringe. I need to get nice a quiet and listen for it better, not just go by the force.
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Yeah. Ours is fairly noisy as long as you have your headset off. It's pulling fuel past a rubber seal through a small hole via suction. It makes a noise like someone sucking through a crushed straw that's vibrating, usually.
 
182q when warm gets no prime. Crank for a few seconds. Wait a few, crank again, fires right up.
 
5QK said:
182q when warm gets no prime. Crank for a few seconds. Wait a few, crank again, fires right up.
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O-470 or the later models? We almost never have to prime when hot, and never need to crank twice, or even crank for more than a few blades.
 
For hot start on our 182P I give it 1 shot of primer, throttle out 1/4", mixture pulled full out (lean), turn key and fires off almost immediately then quickly push mixture back to rich and then throttle to desired idle and lean for taxi. Have never had to turn the key twice. And given my lack of properly giving it a primer shot, the one shot I give it for a hot start maybe isn't doing much. I was told to give if that one shot when hot to give it some nice cool fuel right before the start.
 
Stingray Don said:
Only took me 2.5 years to figure out the lag time for the primer to fill after the pull (see previous thread). I can't hear the primer fill with the headset on. However just yesterday I realized I can feel a slight vibration of the primer as the it fills.

https://www.pilotsofamerica.com/community/threads/cold-starting-procedure-and-im-an-idiot.101190/
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Thanks for posting this link!

So in the end is giving a primer shot while cranking a good practice (For cold start)? It seems to make sense w/r to the fuel being introduced right as it will be needed. And I believe the cold wx startup procedure mentions to do this if needed so it is allowed per the POH in at least one occassion.
 
Sinistar said:
For hot start on our 182P I give it 1 shot of primer, throttle out 1/4", mixture pulled full out (lean), turn key and fires off almost immediately then quickly push mixture back to rich and then throttle to desired idle and lean for taxi. Have never had to turn the key twice. And given my lack of properly giving it a primer shot, the one shot I give it for a hot start maybe isn't doing much. I was told to give if that one shot when hot to give it some nice cool fuel right before the start.
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That sounds like a lot of work. On my 182P for a hot start, I crack the throttle 1/4 inch and turn the key. Fires right up on one blade.
 
Glad to see others using 1/4 inch of throttle. The 1/2 inch ones must be the ones that blow off the ramp.....
 
Sinistar said:
Thanks for posting this link!

So in the end is giving a primer shot while cranking a good practice (For cold start)? It seems to make sense w/r to the fuel being introduced right as it will be needed. And I believe the cold wx startup procedure mentions to do this if needed so it is allowed per the POH in at least one occassion.
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Try three shots of primer, slowly listen and feel while doing this. Then pump the throttle twice, after that leave it about a 1/4 in and start. Been using that technique in my P for years when cold and it catches on the first or second blade.
 
ytodd said:
That sounds like a lot of work. On my 182P for a hot start, I crack the throttle 1/4 inch and turn the key. Fires right up on one blade.
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Same here.

Dirtflyer said:
Try three shots of primer, slowly listen and feel while doing this. Then pump the throttle twice, after that leave it about a 1/4 in and start. Been using that technique in my P for years when cold and it catches on the first or second blade.
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Shouldn't need to pump the throttle. That's also a pretty good way to drop fuel out of the carb and have a cowl fire from raw fuel lying in a puddle inside.

In fact, it's the exact way those fires happen.

That's the entire point of having a primer. So you don't have to do that on an upside down carb.
 
If you prefer to "pump" the throttle to start? Begin to crank the engine first to start a draft.
 
Do you have a analyzer? If so when you do your runup, take your time and watch it and see if anything looks out of uniform.

Also how old are your plugs? Might be worth pulling a couple lower ones and taking a gander
How long ago were your mags serviced or replaced?
Bendix or...slicks?
 
Okay, getting closer!

Last night for the cold start I slowed down and really listened during the priming. I think I can hear what people are mentioning however my ears are pretty bad at higher pitched sounds. I thought I could still hear some kind of filling after I pulled it all the way out. Actually I think I probably did the first shot right and probably rushed the second shot. Anyway, turned the key and about the 3 blade is sounded like it was starting but then didn't so I turned the key off. I gave it more shot (most likely rushed a bit) and it started almost immediately. So that was just 3 on a cold start so you guys are owning me on this one :) I'm thinking I can get this down to two shots!

For hot start, the only reason I give it a primer shot is because someone else recommended it to get some cool fuel in there. I will a hot start with no primer next time. They also recommended starting it LEAN and then immediately back to RICH after it starts...I hope I have that right?

I'm not sure of the age of the plugs. We are at about 50hrs since the top end was redone (previous owner) so hopefully they put in new plugs? Our last annual was in October (about two months after the purchace). There was a broken impulse spring(?) in one mag which our previous mechanic did not catch on the pre-buy (can a pre-buy even detect that?). They are slick mags and one was way past the recommended service (500hrs?) so our mechanic went through both of them. Actually that was our only "surprise" on our first annual after purchase. Oh yeah, the other repair during the annual was a primer 0-ring.

The run up mag checks have been great lately.

Dumb question(s) During the annual do they pull all the plugs and clean/gap or just one per cylinder for the compression check? If they only pull one per cylinder do they pull the lower ones so they can check and clean the ones more likely to foul?

Again your input is awesome. I have never pumped the throttle during startup nor had it every crossed my mind. However, learning how this can be dangerous was a eye opener!!!! Thank you!!!
 
Sinistar said:
They also recommended starting it LEAN and then immediately back to RICH after it starts...I hope I have that right?

...

Dumb question(s) During the annual do they pull all the plugs and clean/gap or just one per cylinder for the compression check? If they only pull one per cylinder do they pull the lower ones so they can check and clean the ones more likely to foul?
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Shouldn't need to do the lean thing on an O-470. The fuel system is about as complex as a lawn mower and cold and hot starts are similar to a lawn mower too. LOL.

The "lean and richer when it catches" is usually a fuel injected engine or a turbo normalized engine technique for hot starts.

No such thing as a dumb question when learning systems and mechanical stuff. I don't know what the written requirements are, but our mechanics have always pulled and checked all plugs.

If you think about it, it would be somewhat silly to only inspect half of them the entire life of the engine, which is what would happen if they only pulled one at inspection time. They'd never see half of them. :)
 
Okay, today tried making just one change on the hot start. I still gave it one primer shot but did not go mixture LEAN (went mixture RICH like a cold start). Started almost immediately. So next time I have to do a hot start (1hr flight followed by 15-20min off) I will also avoid the one primer shot and basically treat it as a cold start with no primer.

I suspected they removed, cleaned and gapped all the plugs but then again I figured I had better ask to be sure!

When I did the first "partial" owner assisted annual I was the one who removed them one at a time (on top) so he could do the compression check. Then he had me remove them all, clean, check gaps, re-install and torque. For other issues (which I won't discuss here) we had to stop using that A&P and went to a highly recommended FBO and I just didn't have the time to owner assist.
 
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