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[d-jnana]

Hi folks back after a long break from boating, and with a problem I'm sure has been addressed many times before.
I have an SC40M in a club 40 boat. It starts and I have almost got the carb tuned in (its an OS carb by the way). It will run fine ubtil you remove the glow igniter, when it dies instantly .
ANY helpful suggestions would be gratefully recieved.

THANKS


( Topic name changed )

[Martin (Admin)]

First thing I would do is replace the plug.
I've had brand new but duff plus.
Also try different type or brand plugs.

Has the engine ever run well before?

Martin.

[d-jnana]

Unfortunatly Martin I don't know if it's everv run well
(e-bay) but the thing with the plugs is ringing bells. I'll try another new one.Thought, if its running too rich could the amount of fuel " chill " the plug? If so (and I can't get it to run any leaner) do you think a hotter plug might help?

[barryfoote]

RECALCITRANT........Modrators, please take this mans name......Does he not realise this is a family run forum?????

Or maybe the word means something else!!!

Sorry guys

[Martin (Admin)]

Hi Footski! ....... quiet day so far is it ?!?

[Stavros]

RECALCITRANT........Modrators, please take this mans name......Does he not realise this is a family run forum?????

Or maybe the word means something else!!!

Sorry guys

Well Footski see this


recalcitrant 
   



Main Entry: re·cal·ci·trant 
Pronunciation: \-trənt\
Function: adjective
Etymology: Late Latin recalcitrant-, recalcitrans, present participle of recalcitrare to be stubbornly disobedient, from Latin, to kick back, from re- + calcitrare to kick, from calc-, calx heel
Date: 1843
1: obstinately defiant of authority or restraint
2 a: difficult to manage or operate b: not responsive to treatment c: resistant <this subject is recalcitrant both to observation and to experiment — G. G. Simpson>


Stavros(should be in the shed but on here instead)

[d-jnana]

Beat me to it Stavros,
I was just about ot say the same
GARY
(d-jnana)

[d-jnana]

However Stavros that doesn't get me (my boat) on the lake.

somebody please help

GARY

[Martin (Admin)]

Also check you have "fresh" fuel.

[OMK]

Mate, the fact the engine dies when you remove the igniter might imply that the engine is running too rich.
Try starting the engine, but leave the glow igniter connected. Then open the throttle for maximum revs and adjust the high-end valve (that's the one with the knurled nut) until it's running fast and smooth, but not screaming. Try to find the happy medium where you get good revs but without running it too lean.
Now throttle back to idle and remove the igniter. If it still dies then you'll probably need to adjust the low-end valve (that's the tiny screw inside the throttle linkage). Make the low-end adjustments while the engine is stopped. But don't turn that screw no more than, say, 1/16 of a turn at a time.

Like Martin said, you might also want to check your glowplug. Connect it to your igniter and you should see a nice orange/red glow.
Although, I'll hazard a guess that your plug is okay, else the engine propbably wouldn't even start at all. So you might start with checking your carb' high-end valve first.

Good luck.

[OMK]

As an aside, see if this is any help.........

http://www.jaxrc.com/gallery/video_viewer.php?id=29

[Martin (Admin)]

Yes, as PMK says!

In line with that:
http://www.youtube.com/watch?v=pEGjExP9GkM

http://www.rctek.com/dyno/nitro_engine_settings.html
http://www.modelsinmotion.co.uk/tamiya_nitro_engine.asp
http://www.rchobbies.org/engine-tuning.htm
http://www.rocousa.com/Traxxas/traxxassetup.htm
http://www.nitrorc.com/articles/2strokepart1a.html
http://www.nitrorc.com/default2.asp?Introduction=http://www.nitrorc.com/reference/etuning.asp
http://www.nitrorc.com/articles/carb/default.asp

[d-jnana]

Thanks Guys,
A lot to be going on with.
Martin...............How fresh is fresh fuel.
The fuel I have is a gallon of moldel technics 5%. It has been in my shed for a while (9 months or so) but has never been opened or the seal broken from buying it new.
Could that be stale.
I am sought of assuming that "stale" furel has been sitting evaporating it's methanol content thus in creasing the concentration of oil, and so making it less volatile and more prone to oiling up plugs. If a container has remained sealed would that not happen, or are there other chemical processes going on to make the fuel less than useful as it ages?

GARY

[Martin (Admin)]

I would say old fuel would be over a year or so, 9 months should be OK.   

[FullLeatherJacket]

Gary

Glow fuel contains 80%-ish methanol, which soaks up water faster than an indifferent single malt. Water in fuel is ungood. If in doubt, sling it out and buy some fresh stuff.

IMHO the Arch Dude is bang on with his appraisal of rich-running, as is whoever suggested trying different plugs (can't see that post here; must have fallen off the bottom of the page).

Hey - if it was all as easy as "out of the box" then it would quickly get boring, wouldn't it?

FLJ (Once designed moggle hairyplanes as well..............)

[bigford]

check to see if your carb to block seal is good (should be a o-ring) mine went bad
and my old o.s. max did the same thing. with that i gave up on glow motors

[OMK]

"FLJ (Once designed moggle hairyplanes as well..............)"

Geez! Is there no end to that man's talents?!
FLJ, as you all know, is the brains behind the Huntsman model boats. In other words, some of the most gorgeous designs ever to hit human eyes.
So, on the strength of that, I reckon it's pretty safe to say that his plane designs are also just as slinky.

Hands up anyone who might join me in pestering the old fart to show us one of his aero plans.

[d-jnana]

Thanks FLJ, but doesn't the water in the fuel just wash the inside of the engine? Seriously though I think its time to invest in another gallon of fuel as well as I have tried just about vevrything else. Including the "O" ring actually my first thought. B***er my heads stuck in the door.

AND I agree with PMK show us yours.
AIRY BUZZERS. I mean.
also like to see some of your huntsman(s)

Thanks to all of you for your advice, it has lead to several hours of productive tinkering whilst I should have been lesson planning and marking, and the cleaner complaining about the caster oil splashed up the wall of my class room as well as the kids all getting high on the fumes. A great Tuesday in fact!

GARY

[barryfoote]

YES::::::Come on FLJ, show us what we want!!!!!!!(planes I mean)..

[OMK]

Gary, pardon me if it sounds like I'm teaching you to suck eggs here, but you don't suppose you might have an air leak somewhere? Is your fuel tank sealed?... etc, etc?

Re: Glow fuel.
I recently found this half-full gallon of fuel. I forgot it was there, but all I know is that it's at least 3, maybe 3 1/2 years old by now. So out of curiosity I had to see if was still usable... and sure enough it is. I'm not exactly sure what the mix is, but (if memory serves) I think it's something like 80% synthetic, 15% methanol and 5% nitro. (At least, I *think* that's what the chap in the shop said).
The label on the container doesn't really give much detail other than the usual "keep away from children" bumph, but the point is, the damn stuff still works okay. So maybe, maybe, your fuel is indeed okay and maybe the problem lies elsewhere.
A pal of mine is using the exact same engine/carb' setup as yours, and reports no bad issues at all with it.

Sorry I can't offer anything more other then the air leakage thing.

[sheerline]

If you intend to hang on to model fuel for a considerable time, the best way to treat it is to getit out of those wretched plastic containers and into a tin can with a good screw down lid which is fully airtight. Have you ever noticed how a fully sealed plastic container caves in and distorts after the stuff has be laying around for a year or so. You checked the lid was really tight and even squeezed the container to make sure there were no leaks and still the container distorted so badly that not even temperature or air pressure changes could cause that amount of  effect upon it.
Well, the story I have on this could just be correct: The molecules of fuel, particularly nitro, are actually smaller than those of the polythene container in which they are held and over time will leech out through the plastic leaving you with a fuel which is depleted in nitro! Also another thing to bear in mind is the aforementioned water content which builds up each time the lid is opened. The fuel is extremely volatile and with such a high evaporation rate it causes moisture in the air to condense out on the fuel and as methanol is missible in water, the two combine and hey presto, your fuel 'goes off' as the water content is too high. In this case, one needs a pump which is  correctly fitted to a sealed metal fuel container, this minimises water absorbtion and nitro depletion.
I have stored methanol fuel for years in sealed steel containers with no apparent ill effects.. even used old tin oil cans which I saved after changing ooil in the car.
Perhaps someone else could shed some light on this and either backup or refute the 'molecules theory' .
Chris

[OMK]

Now that is interesting.
Molecules, etc, is a fascinating subject in its own right. I'm no expert on the matter, other than believing that the fuel would be much better off stored in an airtight metal container. But if you grab another grok of the photos you'll see that the polythene container is still as perfectly formed as the day it was purchased (go figure!). And to to add insult to injury, that same container has been subjected to several seasons of heat, humidity, cold... you name it, yet the fuel itself is still perfectly usable. All the logic in the world is screaming out that the fuel should be stored in a metal container, but in view of what I've just discovered is confusing and contradictory, to say the least.

By the by, if you know where I can purchase a half-gallon metal container (with or without fuel), then could you pse let me know? I hate having to lug around a heavy gallon job all the time, when a lighter half-gallon job would be much better. All the auto accessory shops around here only stock 1-gall containers, but the only place that used to sell them have long gone.

[sheerline]

I see what you mean PMK, I am no expert either and your container certainly defies logic!
Half gallon containers.... I am sure I have seen these in a glassfibre supplies outlet, have a go at ringing round a couple and if they don't have them I am sure they could point you at someone who does as I know they do still exist.

[BJ]

back after a long break from boating,.
an SC40M (its an OS carb by the way

So far you should have checked
New Plug
&
Fresh Fuel

If that has not solved it then look at your slow running jet.
I suggest you take the carb off and clean it thoroughly to make sure that you have no obstructions in the carb and jets before you try again. Go back to your basic settings and try again.
You did not say how long the engine and carb were laid up nor how (or where) they were stored.

[d-jnana]

Thanks BJ

Don't know how long it's been in store (e-bay purchase) but before trying to run it it was stripped of muck and grease in acetone (2 days submersed the stuff) then the carb was treated similarly.
No, I didn't remove anything but the head and the back plate so there is nothing to reseat or bed back in (I've made that mistake before, horendous wear potential).

Tried new plugs, 3 of them, and now new fuel. bit of an improvement, but it was 10% nitro not the 5% I had been using.
So it looks like i'm back to fiddling with the carby. I am begining to think my adjustment increments are too course (1/2 a turn at a time) i'm getting better results with 1/16 at a time.

Still love the engine though it is begging to sound really crisp, even through my home made exhaust.

GARY