paramotormac Posted August 29, 2009 Share Posted August 29, 2009 COULD ANYONE TELL HOW TO GET MORE AIR FLOW IN CARB I HAVE CHANGED FROM THE 32 TO THE 37 WALBRO I HAVE READ COUPLE COMMENTS ON THIS SITE BUT COULD I GET IT IN EASY TO UNDER STAND TERMS AS IM NOT A GREAT MACANIC I NO IT INVOVLES THE BUTTERFLY BIT AND SOME FILLING BUT JUST HOW AND HOW MUCH IS NEEDED WOULD BE GREAT HELP. ANY PHOTOS BE GOOD. KIND REGARDS MAC Quote Link to comment Share on other sites More sharing options...
bendmeroundthehedge Posted August 29, 2009 Share Posted August 29, 2009 Some good info here. http://www.geocities.com/farellus/idle_adaptation.html kev Quote Link to comment Share on other sites More sharing options...
Phil_P Posted August 29, 2009 Share Posted August 29, 2009 The WB32 and 37 carbs are the same choke size as each other, so will flow the same amount of air. The only real difference between them is the way the high jet is situated in the venturi. There has been some discussion that this actually makes the 37 more susceptible to carb icing. The butterfly notching mod will help to improve idle, and transition as you open the throttle, but doesn't increase air flow in total, it simply encourages air over the low speed jet rather rather than it flowing round the whole butterfly circumference. The only way you'll flow more air, is by fitting a larger carb, but is that actually what you want to do? Larger carb also means lower venturi airflow speed, so likely poorer fuel atomisation. Is there a specific problem you are trying to rectify, or are you hoping to increase power output? If it's the second one of the two, you are probably flogging a bit of a dead horse I'm afraid, unless you want to do some porting and polishing work on the internals (or take your engine to Stan Stevens or someone similar). Phil Quote Link to comment Share on other sites More sharing options...
paramotormac Posted August 29, 2009 Author Share Posted August 29, 2009 thanks for reply kev regards mac. Quote Link to comment Share on other sites More sharing options...
paramotormac Posted August 29, 2009 Author Share Posted August 29, 2009 no just been reading bout how better the 37 is over the 32 i noticed the dif when i changed it on a solo machine i had and thought would make improvement on my simonini mini 2, thanks for your help and quick reply, regards mac Quote Link to comment Share on other sites More sharing options...
Farmer_Dave Posted August 30, 2009 Share Posted August 30, 2009 I heard the 37 gives better economy than the 32. I run the Simo200 with a 37 and my 2 stone lighter cousin runs a Simo 200 with a 32 walbro. This isn't a fair comparison because my prop's 50mm bigger and geared differently, but on the same wing he burns proud of 5 litres an hour and I use 3.3 lt/hour. I'm about to fit the 37 to his unit, so will update you when we've done some tests. Dave Quote Link to comment Share on other sites More sharing options...
outkast Posted August 30, 2009 Share Posted August 30, 2009 I changed my tilottson to a walbro 37 on my solo powered machine, at first I could not get the idle smooth until I performed the butterfly mod, now it runs sweet as a nut. Dave. Quote Link to comment Share on other sites More sharing options...
paramotormac Posted January 6, 2010 Author Share Posted January 6, 2010 any ideas on how to reduce carb icing Quote Link to comment Share on other sites More sharing options...
Phil_P Posted January 6, 2010 Share Posted January 6, 2010 Duct some warm air from round the cylinder head, or better yet, the exhaust, to your air intake. Make it an easy to remove mod so that in low icing conditions you can dispense with it to get max power. Or fit a flap valve so you can turn 'carb heat' on and off, a la GA aircraft. Ultimately, fit fuel injection Quote Link to comment Share on other sites More sharing options...
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