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new 46 la won't start at all! - 7/21/2008 3:09:20 AM   
jayad


 

Posts: 2
Joined: 6/14/2008
From: , AB, CANADA
Status: offline 		Just bought a new os 46 la and it won't start. my electric starter (which has started many, many engines over the years), won't even turn it over. i can get it spit and sputter by hand starting. Also, there seems to be alot of fuel coming from the carb when it is turned over??? This is my first OS. Other engines are ASP, GMS.
Please, someone with more experience than I !
       Post #: 1

RE: new 46 la won't start at all! - 7/21/2008 5:16:49 AM   
rainedave



Posts: 5175
Joined: 7/21/2005
From: Greensboro, NC, USA
Status: online 		Be careful with your electric starter! If the carb is spitting fuel it is probably flooded. You can easily bend or snap the connecting rod using an electric starter on a flooded engine. That's probably why it's hard to turn over. It's called hydraulic lock.

Disconnect the fuel tubing from the carb and remove the glow plug. Then, hit it with the starter. I'll bet lots of fuel sprays out of the top (so, lean back when you do it).

Then, set the needle valve to 2 1/2 turns open, put the plug in and the tubing back on. It should start.

David

(in reply to jayad)
       Post #: 2

RE: new 46 la won't start at all! - 7/21/2008 5:44:58 AM   
the pope


 

Posts: 172
Joined: 4/17/2005
From: goolwasa, AUSTRALIA
Status: offline 		Some of the LAs can be very tight and maybe the heat gun on the head may help before start up as well as checking for a flooded engine as rainedave mentioned. Cheers the pope

(in reply to rainedave)
       Post #: 3

RE: new 46 la won't start at all! - 7/21/2008 8:57:24 AM   
whodeany99


 

Posts: 24
Joined: 4/22/2008
From: Melbourne, AUSTRALIA
Status: offline 		I have a OS 46LA that i bought for my trainer and I have the same problem, flooded or not. One thing I have noticed is with this engine it runs backwards 50% of the starts. It has about 20 flights on it and even when not flooded it wont start straight off the starter, its just too tight. I have to run the starter and then while it is running then put it on the spinner (prop is wound back clockwise to the compression stroke, so it gives the engine a chance at pushing through the compression stroke when starting)...... Its a harsh way of doing it but it works. Ive tried everything to free it up but even with 20 flights its still like it has hydraulic lock, even after running it and trying to start it again instantly. When mine starts and runs backwards it splutters and spits fuel out of the carb, and wont run past 1/4 throttle, just check that it isnt running backwards. Mine will run backwards about 80% of the time when hand starting. Not sure if it helps but its just something i found.....

< Message edited by whodeany99 -- 7/21/2008 10:00:11 AM >

(in reply to jayad)
       Post #: 4

RE: new 46 la won't start at all! - 7/21/2008 9:24:36 AM   
cymaz



Posts: 52
Joined: 8/12/2007
From: Bodmin, UNITED KINGDOM
Status: offline 		Hi

As mentioned previously make sure you dont hydraulic lock the engine. Put the needle valve in fully unscrew it by 2 turns. Plenty of glow heat and a dash of fuel into the carb and set it on idle. Then flick over by hand or bonce the prop backward on the compression and it should fire.

Silly question- glow plug OK??????????????

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       Post #: 5

RE: new 46 la won't start at all! - 7/21/2008 3:37:16 PM   
DarZeelon



Posts: 7083
Joined: 4/9/2003
From: Rosh-Ha'Ayin, ISRAEL
Status: online
quote:

ORIGINAL: whodeany99

...One thing I have noticed is with this engine it runs backwards 50% of the starts.



Hoodini (?),


An engine starting in reverse rotation is the surest sign that it was over-primed...

Also, your engine seems to have not undergone a full break-in, which is urgently needs.


Please read this RCU thread, to understand the technique and the purpose of the break-in, in your tapered-bore engine.


< Message edited by DarZeelon -- 7/21/2008 3:38:33 PM >

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       Post #: 6

RE: new 46 la won't start at all! - 7/21/2008 3:40:43 PM   
Bax


 

Posts: 12451
Joined: 4/26/2002
From: Champaign, IL, USA
Status: online 		If you try to start an engine and it run backwards, you have it much too rich. Non-ringed engines can be run too rich. You need to run them no richer than just lean of the point where the engine is running just above the point where it breaks back into 4-cycle mode. NEVER run a non-ringed engine in 4-cycle mode. As soon as the engine will accept it, you can lean the engine towards peak RPM. A fuel with castor oil in the mix is essential. The more castor, the better. We'd use a 10 x 7, 10 x 8, or 11 x 7 prop for general running and breakin.

< Message edited by Bax -- 7/21/2008 3:41:20 PM >

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(in reply to cymaz)
       Post #: 7

RE: new 46 la won't start at all! - 7/21/2008 4:24:33 PM   
dennis



Posts: 1290
Joined: 1/7/2002
From: Minersville, PA, USA
Status: online 		I've never used an electric starter on any of the OS LA engines. They are all used on C/L models and the drill is to choke about 4 turns, flip over about 12 times, hook up your battery, turn ovr feel the bump, flip once and it starts religously. This drill has worked for more engines then I can remember and usually for hundreds of flights.
dennis

(in reply to Bax)
       Post #: 8

RE: new 46 la won't start at all! - 7/21/2008 4:45:44 PM   
DarZeelon



Posts: 7083
Joined: 4/9/2003
From: Rosh-Ha'Ayin, ISRAEL
Status: online 		Dennis,


With the two-stroke engines I have used:....

After seeing the fuel has reached the carburettor, choking just one more turn is usually enough.

If the engine is still reluctant to start, one more turn always makes it change from STOP to GO...


I guess 3-4 turns total would make up for the fuel needing to get to the carburettor first.



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       Post #: 9

RE: new 46 la won't start at all! - 7/21/2008 10:20:43 PM   
rcdude7


 

Posts: 1016
Joined: 4/12/2003
From: Maryland
Status: offline 		Flooded engine + electric starter = broken engine.

Be glad your starter won't turn it over as this may have saved your engine from damage. I use a starter battery with several hunderd cold cranking amps available and have bent the rod in a SF .40 before learning my lesson. The engine was repaired with a new rod BTW.

(in reply to jayad)
       Post #: 10

RE: new 46 la won't start at all! - 7/23/2008 1:32:52 AM   
whodeany99


 

Posts: 24
Joined: 4/22/2008
From: Melbourne, AUSTRALIA
Status: offline 		DarZeelon:

The engine has been run in as per the manual's run in procedure with 4 tanks before attempting to fly. It now has around 30 tanks through it, soon it will need a rebuild . Its fully run in thats for sure and tuned to just below peak rpm's like all my other O.S. engines. Even without priming the engine runs backwards 50% of the time (must have been a left handed guy that assembled it at the factory). From the time i took it out of the box it would lock up on the compression stroke to the point where i couldnt turn it in my hand with a prop on it. All my other engines are O.S. and they start and run like a dream, its only the LA that plays funny buggers with me.....


< Message edited by whodeany99 -- 7/23/2008 2:17:53 AM >

(in reply to DarZeelon)
       Post #: 11

RE: new 46 la won't start at all! - 7/23/2008 7:05:51 AM   
DarZeelon



Posts: 7083
Joined: 4/9/2003
From: Rosh-Ha'Ayin, ISRAEL
Status: online
quote:

ORIGINAL: whodeany99



The engine has been run in as per the manual's run in procedure with 4 tanks before attempting to fly.



Hoodini,


That's exactly the point!

Please read Bax's input here, in addition to the procedure I outlined.

Bax says you must never break-in your engine at a four-cycle rich setting, as I do in my procedure...

The manual, on the other hand, specifically tells you, on page 23, to run one full tank through the engine, with the needle set 180º rich from optimal flight setting... That is about ¾ of a turn rich from peak RPM!

This will produce a rich, four-cycle running, which both Bax and I tell you NOT to do...


This manual is wrong and quite possibly, promotes much more initial wear into the engine, than would a correct break-in.

quote:



It now has around 30 tanks through it, soon it will need a rebuild .



Don't make me laugh! I am totally serious here!

This is one of the more unwise statements I have read in these pages...


An ABC engine should last 400 hours, following a correct break-in procedure (that's 2,400 10 minute tanks!).

Engines with a somewhat less durable ABN setup should theoretically not endure that long, but the Thunder Tiger .46 Pro and the Webra .50 GT engines; both ABN, do reach that 400 hour benchmark, as observed by Dr Nitro, a tester for one of the model fuel manufacturers.

If your engine need a rebuild after just 1% of this projected life expectancy, you are doing something terribly wrong!


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RE: new 46 la won't start at all! - 7/23/2008 1:00:00 PM   
Sport_Pilot



Posts: 7718
Joined: 1/21/2002
From: Acworth, GA, USA
Status: online 		I for one disagree, many ABC engines can be run in a rich four cycle. It all depends on the fit, taper, and heat expansion designed in the engine. Fox and others, including Jett, have designed ABC stunt engines which are specifically built to run in a four cycle mode. If the manufactures instructions result in a rich four cycle running it is probably OK to do so. I have seen OS LA's broken in and run like this without damage.

I have noticed that tight engines are more likely to start backwards, however they are still overly rich when they do so. Engines with small carbs such as the LA can be overprimed without choking if a full tank level is well above the carb, just a few flicks would do this, especially when hot.

< Message edited by Sport_Pilot -- 7/23/2008 1:03:34 PM >

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RE: new 46 la won't start at all! - 7/23/2008 2:26:22 PM   
rainedave



Posts: 5175
Joined: 7/21/2005
From: Greensboro, NC, USA
Status: online
quote:

ORIGINAL: Sport_Pilot
...Engines with small carbs such as the LA can be overprimed without choking if a full tank level is well above the carb, just a few flicks would do this, especially when hot.


Good point. jayad, how is your engine mounted? Is it in a test stand - like it should be for breaking in? Or, is it in your plane? If it's in your plane the tank might be too high as Sport_Pilot explained.

When you have trouble with an engine the first thing to do is mount it on a test stand. Engine trouble shooting is a process of elimination; checking one thing at a time. It's just too complicated and frustrating to try and do it with the engine in a plane.

If you get the engine running good in the stand, then you know the problem is with the fuel system in the plane.

So, make lfe easy on yourself.

David

(in reply to Sport_Pilot)
       Post #: 14

RE: new 46 la won't start at all! - 7/23/2008 5:59:44 PM   
DarZeelon



Posts: 7083
Joined: 4/9/2003
From: Rosh-Ha'Ayin, ISRAEL
Status: online
quote:

ORIGINAL: Sport_Pilot

I for one disagree, many ABC engines can be run in a rich four cycle. ...Fox and others, including Jett, have designed ABC stunt engines which are specifically built to run in a four cycle mode.



Hugh,


Many control-line stunt engines are ABC.
But even then; during break-in, running them at a four-cycle rich setting would be ill-advised.

Even engines designed to be run rich during their normal life-span, should be broken-in only at a slightly rich setting, to get the cylinder sleeve hotter and properly expanded.


_____________________________

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(in reply to Sport_Pilot)