heyo,

just trying to get my whipper snipper engine cranking and havent had much luck...

just need some advice regarding the tuning screws. not sure which way to turn them or where they should be set at all.... the engine would start and run at full power then die when youd let go of the throttle. this engine has two screws with H and L on them, presumably high and low throttle settings..

also wrt the spark plug. not sure if its working anymore either. i took the plug out of the engine and tried cranking the engine over but couldnt see it spark... im guessing that means its dead?
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With the spark plug bit, did you earth the metal threads of the spark plug to the engine casing when you tested it ? It completes the circuit through there. If it wasnt earthed, then it wouldnt have been sparking and thats normal, but if it was earthed, then yeah, either the spark plug, coil, or some part along the way is dead.
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yeah that must have been the case.... but on a side note i got the engine firing... turns out the thing was out of gas hehe

found a good site too that said how to tune an engine.. rev it to 1/4 power, tune the low setting till it sounds good, then go to full and tune it, then repeat that.
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Lol thats saves me makeing a long winded post

put it this way
if it wasnt sparking then it wouldnt run at all ;->

be carefull doing the "hold it on the block" spark plug test, typically theres a nicley mixed fuel air combo coming out the hole where the spark plug was just looking for an ignition source.
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Mechanical engineers build weapons, civil engineers build targets

ouch yeah i should probably be careful about that test too

got most of the engine apart, theres ONE screw thats keeping the rest of the casing on and i cant take any more of the engine apart before that one bolt comes out. its jammed in nice and good. problem is the bolt is right near the gas tank and i dont want to put my butane torch near it to try loosen it up or anything. any ideas how to get this bastard bolt out? i tried tapping it with a hammer to see if trhat would loosen it but no success.

ahhh and another thing thats interesting me now, whats the purpose of the big flywheel? i can see theres some copper strips on there that presumably generate the spark for the spark plug and the starter assembly engages onto it... but what does it do in relation to keeping the engine going aside from that?

oh yes and i tried to modify the little pull cord adaptor to fit into a drill to start the engine, but couldn't think of a way to do this... how did you go about it andrew? i ended up shoving a square bit in a drill with the clutch on and shoved that in the end of the shaft and tried to crank the engine over but it seems a drill cant turn the shaft fast enough to make the engine start...

and another thought that passed my mind, the fuel is fairly heavy so does it get counted in the weight of the robot? like how CO2 and air doesnt get included.

but none the less im glad i got the engine, many interesting and fun things to play around with
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Last edited by Glen on Tue Oct 25, 2005 7:33 pm; edited 1 time in total

With the fuel, how about fitting a much smaller tank that can just hold enough for 5 minutes of full power? I seem to recall most event rules limiting the maximum fuel a bot can carry in any case.

Perhaps asking Jef J about model plane fuel systems with positive pressure feed will help too...
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The fly wheel has several purposes .One is to cary the magnets for the magneto ignition the second is to store some energy to keep the engine turning after the power stroke to turn the motor over against compresion for the next stroke The third on an air cooled motor is to act as a fan to push air past the cylinder fins and the head to cool the engine .The outer motor caseing is also an important part of the cooling system .

Whiper snipers use a diaphrame carby that can work in any direction and they incoperate their own lift pump in the carby that works with crankcase vacume .

Also with the tight screw use an impact screwdriver on it if you have one or can borow one.

wrt the fuel tank, no doubt if i where to stick it in anything robotic i will be putting in a smaller fuel tank, this thing takes about 1-1.5L of fuel at a time so im guessing thats way too much.

and i also realised the horror of trying to wind one of those wound up springs into the pull starter mechanism, quite possibly the worst thing ive attempted to do lol

and when i finally get the rear casing off, i want to take apart the cylinder head to clean everything up as i can see bits of rust on top of the piston through the spark plug hole in addition to there being big pieces of something around the edges of the ports... do i just take the cylinder casing (the thing with the fins on it) off or should i just not bother taking it apart?

ahhh thinking of more questions lol... oh yeah is it safe to operate the engine without the front casing on? just want to make sure the flywheel isnt going to launch off and start riccocheting around

hehe yeah i was thinking that screwdriver will be a good investment after reading this -

http://www.factsfacts.com/MyHomeRepair/screwit.htm
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http://www.youtube.com/user/HyzerGlen - Videoooozzz

quote:

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i ended up shoving a square bit in a drill with the clutch on and shoved that in the end of the shaft and tried to crank the engine over but it seems a drill cant turn the shaft fast enough to make the engine start...

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nah i was speaking about setting the clutch on the drill so that if the engine did fire it would sort of slip and not rip my arms to pieces, turns out the engine doesnt have a clutch on it

i was looking at the VI videos with a lot of interest, not sure if there flywheels are different to mine but the adaptor kind of slips over the shaft and then engages into the flywheel. because the shaft goes through the adaptor it makes things a whole lot trickier

heres a pic of it...

http://photobucket.com/albums/v357/Cobrarobotics/misc/?action=view&current=DSC02111.jpg

ill re-assemble the rip cord setup for now and think that one over anyway did i mention I.C.E's ARE THE BEST
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www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

No clutch.....

Get another motor A lot easier then trying to modify the current motor to fit one on. Use this motor as your learning 'victum' and find one with a clutch for your real purpose.
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often the clutch is half on the engine and half on the whipper snipper shaft, and usually held together by the casing on the end of the shaft.
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