tomposh101 Posted May 16, 2008 Share Posted May 16, 2008 I'm hoping that someone more technically minded than me or who has experienced the same problem as me can help I have a PAP Top 80 paramotor and the engine cuts out when it is rolled on its cage one way (about 20 degrees) and not the other. This is a simulated throwing it over my shoulder move as if to place it on my back where the problmes lie as I like to idle it before putting on. My temporary fix is putting it over the opposite shoulder first (so that it does not tilt the way that it cuts off). Also when applying full throttle the prop rough runs and the power declines (I have checked the display and this seems to happen over 9600rpm so I am guessing it is a safety to stop the engine over reving, it is a lighter prop than the original only because its a cheap replacement to the one I had before). Things I have done so far (that improved the tick over substantially.. 1) Cleaned the jets and the carb 2) Cleaned the bore (there was a quarter of a cotton buds worth of swarf in the jets and bore together ) 3) Checked the oil level in the clutch. (the bleed thingy does seem to excrete rather a lot of oil). That is the top of my technical experience.. please help me from here Quote Link to comment Share on other sites More sharing options...
pete_b Posted May 16, 2008 Share Posted May 16, 2008 I'm hoping that someone more technically minded than me or who has experienced the same problem as me can help I have a PAP Top 80 paramotor and the engine cuts out when it is rolled on its cage one way (about 20 degrees) and not the other. This is a simulated throwing it over my shoulder move as if to place it on my back where the problmes lie as I like to idle it before putting on. My temporary fix is putting it over the opposite shoulder first (so that it does not tilt the way that it cuts off). Also when applying full throttle the prop rough runs and the power declines (I have checked the display and this seems to happen over 9600rpm so I am guessing it is a safety to stop the engine over reving, it is a lighter prop than the original only because its a cheap replacement to the one I had before). Things I have done so far (that improved the tick over substantially.. 1) Cleaned the jets and the carb 2) Cleaned the bore (there was a quarter of a cotton buds worth of swarf in the jets and bore together ) 3) Checked the oil level in the clutch. (the bleed thingy does seem to excrete rather a lot of oil). That is the top of my technical experience.. please help me from here The engine should run in any orientation even upside down as long as the fuel pick up is in the fuel. Did you clean the very fine filter in the carb?? What do you mean "the prop rough runs and the power declines"?? The prop may look the same but they can cause max rpm to be different from the previous one. Pete b Quote Link to comment Share on other sites More sharing options...
tomposh101 Posted May 16, 2008 Author Share Posted May 16, 2008 Thanks for replying so quickly Pete It's more the engine than the prop.. the power delivery is smooth up to 9600rpm then if I hold the throttle fully open it goes all jelly belly with the engine dropping power, gaining a little more (always declining on each cycle) until finally it cuts out after 5-10 seconds. The filter is spotless, as are the jets now. Cheers Quote Link to comment Share on other sites More sharing options...
pete_b Posted May 16, 2008 Share Posted May 16, 2008 Is the mixture set right? are you sure that there are no places that the fuel pipe is creased ect, as it sounds as if it is slowly starving it self of fuel. Have you taken the plug out to see what color it is? Pete Quote Link to comment Share on other sites More sharing options...
Guest Posted May 16, 2008 Share Posted May 16, 2008 Yes plug colour (around the ceramic surrounding the central electrode) is vital at times like this. What carb is fitted to the Top 80 (WB32, WB37 or WG8 most likely)? WRT the cut out when leaning the engine over - that could well be a short in the kill switch curcuit (possibly also causing the top end problem but that sounds more likely to be carburation). Quote Link to comment Share on other sites More sharing options...
Mike Posted May 16, 2008 Share Posted May 16, 2008 Two things l think it could be, one already mentioned is a short in the kill switch circuit or there is a pinched area of your fuel line. Nothing else l can think of would give you the trouble just by leaning to one side. IMO. Regards Mike Quote Link to comment Share on other sites More sharing options...
Guest Posted May 17, 2008 Share Posted May 17, 2008 If it's a diaphragm carb then (like a Walbro or Mikuni) it should be completely independent of orientation to work properly however if the carb has been swapped for a float type (such as a Bing) then then the engine needs to maintain a more or less vertical position. The Bailey uses a float carb which can flood if you spend too long leaning forward while standing up. Quote Link to comment Share on other sites More sharing options...
tomposh101 Posted May 18, 2008 Author Share Posted May 18, 2008 Thanks guys so far. I've had a very experienced friend look at the PAP now and he says that one of the valves on the main jets in the carb has been scored (on the brass?) by something like a screwdriver. He says it is only hair line but means that at idle this now allows the mixture to be too rich which causes the engine to cut out on idle but not when the throttles been opened up. Does this sound right? He reckons it would be easier just to replace the carb and I have seen on sky dragons website that retail at over £150 for the Walbro (that mine is) or there is one for £75 on the same site that does not appear to be branded. Any body who could recommend a Carb for my PAP? Thank you so far. Quote Link to comment Share on other sites More sharing options...
Guest Posted May 18, 2008 Share Posted May 18, 2008 Sorry Tom but this does not make any sense. The main jet does not come into play at idle/low revs. There are small holes (idle jets) in the body of the carb (not brass like the main jet) that deal with the low rpm fuelling. If the main jet has a score mark (which wouldn't really give you the symptoms mentioned) then the main jet can be replaced (for pennies) without having to replace the whole carb. Contact Rowena Motors as they sell overhaul kits and whole Walbro carbs for half that price (even cheaper from the States) if a replacement is really necessary. What model of Walbro is it? Is there any possibility that the guy is talking about screwdriver damage to the diaphragms, etc? If so an overhaul kit is about a tenner from Rowena. Even then that could be the problem with the top end but the cut out when angled at low rpm is certainly nothing to do with what he describes. Where in the UK are you? If you are in the south-east perhaps we can meet. PM me and I'll give you my numbers. Edit - just done a bit more reasearch and I see that the standard carb for the Top 80 is a Walbro WG8. This carb does not have a Hi adjustment screw for top end fuelling adjustment so instead you just fit a different size main jet (simple screw in job). The Ros 125 engines have this carb fitted and recently PAP decided that they were under-jetted (not enough fuel flow for high revs) so owners had a choice of either fitting replacement main jets or just drilling out their existing brass main jets to a bigger size (as specified by the bulletin). The idea if binning an entire carb because the main jet has been scratched is ludicrous. Is there more to this than you have been able to understand in his explanation? Quote Link to comment Share on other sites More sharing options...
tomposh101 Posted May 18, 2008 Author Share Posted May 18, 2008 Hello v23nb, I'm in Shropshire so a little far away, thanks He did mention that it was screwdriver damage so you are closer to the mark than I am. It is a 24mm WG8 carb. Cheers. Quote Link to comment Share on other sites More sharing options...
Guest Posted May 18, 2008 Share Posted May 18, 2008 (edited) Take a look at the following website http://www.wind-drifter.com/technical/wg8walbro.htm Halfway down you will see the opened up carb showing underneath the pressure compensating diaphragm. Near where the metering lever is located is a brass circle with a slot cut in it and a hole in the center. This is the main jet and the slot is to allow a screwdriver to remove it and replace it. If someone has loctited it into place the the slot may be damaged after someone has tried to remove it! I can't see how the bore of the main jet could be damaged by a screwdriver and it doesn't have any valves. If the main jet is free of blockage it should not be causing any problems even if the screwdriver slot is damaged. Edited May 18, 2008 by Guest Quote Link to comment Share on other sites More sharing options...
Guest Posted May 18, 2008 Share Posted May 18, 2008 These guys are the mutts nuts for carb problems... http://www.rowenacarbs.co.uk/ Quote Link to comment Share on other sites More sharing options...
pete_b Posted May 18, 2008 Share Posted May 18, 2008 Hello v23nb,I'm in Shropshire so a little far away, thanks He did mention that it was screwdriver damage so you are closer to the mark than I am. It is a 24mm WG8 carb. Cheers. Where abouts in Shropshire I'm in Lydbrook Gloucestershire A good garden machinery workshop should be able to sort it out. Pete b Quote Link to comment Share on other sites More sharing options...
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