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04-07-2009, 08:11 PM
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um, drill and tap a hole into the inlet manifold, between the carbie and the head, attach a hose fitting, hose, and connect that to the fuel pump  thats the normal vaccuum take-off point for any engine
fuel pumps suck for priming after running out of fuel, be warned... and usually require some sort of regulator/return to tank setup...
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04-07-2009, 11:06 PM
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thanks headmess, have searched the net and found a few different answers, tapping into the crank case and tapping into the inlet manifold as you suggested. think the inlet manifold seems to be the go. cheers.
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04-07-2009, 11:18 PM
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yeah, um...just remove it before drilling and tapping
and wtf sort of idiot said to tap into the crankcase? what with piston blow by and all that, its always at positive pressure when running...to the point that my model nitro 4stroke uses that as the way to pressurise the tank instead of an exhaust take off like the 2 strokes use....
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05-07-2009, 12:17 AM
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Originally Posted by headsmess yeah, um...just remove it before drilling and tapping
and wtf sort of idiot said to tap into the crankcase? what with piston blow by and all that, its always at positive pressure when running...to the point that my model nitro 4stroke uses that as the way to pressurise the tank instead of an exhaust take off like the 2 strokes use.... | The model engines that run off nitro fuel are all 2 stroke...
They pressurize the tank because the fuel and engine both sit level with each other (give or take a little) so it cannot be gravity fed. So it needs to be pushed through.
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05-07-2009, 12:24 AM
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ahem...whats this then? you obviously arent into the model car/ plane/heli scene O.S. Engines O.S. FS-26S-CX (Recoil)
and model engines arent gravity fed....the ones without pressure nipples use plain old venturi effect...ie the fuel tank is basically the bowl of a normal carbie... so theyre kept level so they can actually suck the fuel up...
these have the problem of running rich when the tanks full, and then getting leaner as it empties out. the whole reason they now use pressurised tanks
venturi effect... what a carbie and sprayguns/airbrushes use.... also much the same as the lift a wing produces. except a wing also uses "angle of attack"
Last edited by headsmess; 05-07-2009 at 12:33 AM.
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05-07-2009, 10:09 AM
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2 stroke gokarts use a diaphram type pump connected to the crank case. The pulsing crank case pressure occilates the diaphram and pumps the fuel. Same as a whipper snipper.
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05-07-2009, 06:14 PM
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Originally Posted by tormentandglory 2 stroke gokarts use a diaphram type pump connected to the crank case. The pulsing crank case pressure occilates the diaphram and pumps the fuel. Same as a whipper snipper. | total agreeance with this one T&G  most small petrol 2strokes use a diaphgram carbie. basic advantage? they can be inverted cause they dont have a bowl full of fuel...
and the lil mini pocket rockets use just a bowl and gravity feed, like most 2 stroke bikes(and my tuk tuk  ), but with a bit of work they can be modded to use a diaphgram carbie... like that fat arsed 25mm one i pulled off of an old solo chainsaw...
i also have an old sachs rotary engine that has a diaphgram carbie,but uses a seperate fuel pump that taps into the chamber somewhere on the compression...um...would stroke be an appropriate term on a rotor?
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05-07-2009, 06:26 PM
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