leerobo Posted November 30, 2011 Share Posted November 30, 2011 Been out today with my ftx punisher and had a good time,been doing some speed runs etc.. My problem? is that my priming bulb is empty when i have been running it, is this a problem or normal its just that my other rc car that i have didnt go empty, i allways known it as being half full. i also have a cyf270 engine thanks Lee Quote Link to comment Share on other sites More sharing options...
stebro Posted November 30, 2011 Share Posted November 30, 2011 Never known the primer to be empty unless it ran out of fuel. Is it possible you cut it off before it died? Quote Link to comment Share on other sites More sharing options...
leerobo Posted November 30, 2011 Author Share Posted November 30, 2011 no thats when its still running, i start it run it for about 10 mins bring it back and the bulb is almost empty a tiny bit in the bottom of it Quote Link to comment Share on other sites More sharing options...
toys4x4boys Posted November 30, 2011 Share Posted November 30, 2011 The bulb should stay half full ideally. Could be popoff pressue wrong in the carb ? Blocked tank vent ? Kinked fuel lines ? Quote Link to comment Share on other sites More sharing options...
leerobo Posted November 30, 2011 Author Share Posted November 30, 2011 no kink in fuel lines could it be a blocked fuel filter? Quote Link to comment Share on other sites More sharing options...
dwarfy Posted November 30, 2011 Share Posted November 30, 2011 Somebody posted a similar thread on LSF the other week and those in the know said it was running lean if the bulb was empty. Kill your engine immediately after a high speed run without letting it idle and check your plug colour. This will give a good indication of your mixture - light brown is lean, choc brown ideal and dark brown or black is rich. Quote Link to comment Share on other sites More sharing options...
stebro Posted November 30, 2011 Share Posted November 30, 2011 Somebody posted a similar thread on LSF the other week and those in the know said it was running lean if the bulb was empty. Really. If that true that good to know but i can't see how Quote Link to comment Share on other sites More sharing options...
dwarfy Posted November 30, 2011 Share Posted November 30, 2011 1 of the guys on there races FG's and was told this by Ian Oddie. I would like to think he knows a thing or 2 about engines!! Quote Link to comment Share on other sites More sharing options...
toys4x4boys Posted November 30, 2011 Share Posted November 30, 2011 You'd think lean meant not using enough fuel, so the bulb would be full ? Unless it's somthing not allowing enough fuel to be drawn, making it run lean. But I don't see needle settings doing it. Quote Link to comment Share on other sites More sharing options...
dwarfy Posted November 30, 2011 Share Posted November 30, 2011 You'd think lean meant not using enough fuel, so the bulb would be full ? Unless it's somthing not allowing enough fuel to be drawn, making it run lean. But I don't see needle settings doing it. Must admit I thought the same! Quote Link to comment Share on other sites More sharing options...
toys4x4boys Posted November 30, 2011 Share Posted November 30, 2011 This is a great link for carb issues and understanding http://www.helifreak.com/showthread.php?t=326599 Primer Bulb Empty If the motor leans out unexpectedly and you look at the carb and see that the primer bulb is empty (or is emptying out in front of your eyes) then before doing anything feel the carb on the inside edge of the regulator side of the carb. If it is excessively hot look at the cooling shroud to see if its possible for hot air can be blowing on the carb. If it is hot try blocking (I've literally used aluminum foil for this) where that air is coming out and fly the model to see if it stops emptying the primer. If it does, this is the problem you need to address. Some models like the Spectra G include a carb shield that is there for this very purpose. I have ONLY seen this problem on PUH models, I've personally NEVER seen this happen on an RC format model. The cooling shrouds are usually very different on those motors. I talked with Luis Salas at Walbro (he's the guy that WROTE the Walbro Service Manual) about why he thinks this happens. He indicated that this was a problem that they did not see regularly so he didn't have a good explanation for why it would happen. However from digging through the carburetor remember there is a port that runs directly from the primer bulb to the main fuel reservoir. If for some reason there is more vacuum than fuel in the reservoir it can pull it from the primer bulb. This is obviously what is happening, its less clear exactly why. All I can say is that EVERY time I've ever seen this happen, blocking the air flow onto the carburetor has resolved it. In my experience even replacing the carburetor hasn't resolved this problem. If you've had different experiences or resolved it a different way I'd like to hear it. Quote Link to comment Share on other sites More sharing options...
dwarfy Posted November 30, 2011 Share Posted November 30, 2011 clear as mud now!! Quote Link to comment Share on other sites More sharing options...
stebro Posted November 30, 2011 Share Posted November 30, 2011 clear as mud now!! Haha yep. Think it just going to be 1 of those things mate Quote Link to comment Share on other sites More sharing options...
leerobo Posted November 30, 2011 Author Share Posted November 30, 2011 Been talkin to nige at freeprawn racing and he said- Hiya, No it shouldn't empty. It normally means your running the car lean. Try richening up the 'H' needle by screwing it out a tiny amount at a time till is back to normal. Regards, Nige. Quote Link to comment Share on other sites More sharing options...
toys4x4boys Posted November 30, 2011 Share Posted November 30, 2011 Cool, if that sorts it, that's a nice easy fix Quote Link to comment Share on other sites More sharing options...
stebro Posted November 30, 2011 Share Posted November 30, 2011 Been talkin to nige at freeprawn racing and he said- Hiya, No it shouldn't empty. It normally means your running the car lean. Try richening up the 'H' needle by screwing it out a tiny amount at a time till is back to normal. Regards, Nige. well we learn something new every day Quote Link to comment Share on other sites More sharing options...
dwarfy Posted November 30, 2011 Share Posted November 30, 2011 thats why Nige and Ian Oddie are in the business!! Quote Link to comment Share on other sites More sharing options...
leerobo Posted November 30, 2011 Author Share Posted November 30, 2011 thanks for all the advice, will be trying it out this weekend and ill get back to you all. Quote Link to comment Share on other sites More sharing options...
Dan Garf Posted December 3, 2011 Share Posted December 3, 2011 have you found out what was wrong Quote Link to comment Share on other sites More sharing options...
nitro-basher Posted March 12, 2012 Share Posted March 12, 2012 (edited) old thread, but............ replaced my 603 with a 813, now first thing i noticed even with the primer bulb primed to test the carb, engine it wouldnt start, tried every thing untill i thought id connect up the tank, and then walla it started, but on my 813 the bulb emptys completely, but it still runs fine, the problem i have is if i adjust the H needle in or out i get poor top end. same as for the low. i have the needles set perfectly for low and high, but the bulb still emptys! as for heat were can i get this heat shield? of is it some thing i can fabricate? Edited March 12, 2012 by nitro-basher Quote Link to comment Share on other sites More sharing options...
Bigjimknickers Posted October 24, 2014 Share Posted October 24, 2014 Hmm, Ive noticed this primer bulb emptying before my eyes on my 668 & F270 engine, plus its not revving cleanly at max revs, but only when hot? Pretty odd? Quote Link to comment Share on other sites More sharing options...
HarveyC Posted October 25, 2014 Share Posted October 25, 2014 Tank Vent Blocked?? Harvey Quote Link to comment Share on other sites More sharing options...
mark35 Posted October 25, 2014 Share Posted October 25, 2014 Good luck tuning the 813 its pants mate you should have got a 990. if you have trouble starting it just open the low needle half turn so you know where it was an it'll fire no probs Quote Link to comment Share on other sites More sharing options...
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