Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision
Previous revision
techtalk:evo:carb02 [2019/11/10 03:38]
ixl2relax [Enrichener Function (Choke)]
techtalk:evo:carb02 [2020/05/31 03:42] (current)
ixl2relax [The Idle Drop Method (IDM)]
Line 76: Line 76:
 This is from an [[http://​xlforum.net/​forums/​showthread.php?​t=30748|XLForum thread]]: chrishajer wrote - CBAS5 and I were talking about what it should sound like, good, and we filmed that one. Then he said "you know, we should show a bad one too" so we did that. I think the [vacuum] sound and the speed that the slide comes down are the two most important things. Those things you can't describe to someone really. I can't anyway. But it's absolutely the best way to verify that the diaphragm is seated properly. This is from an [[http://​xlforum.net/​forums/​showthread.php?​t=30748|XLForum thread]]: chrishajer wrote - CBAS5 and I were talking about what it should sound like, good, and we filmed that one. Then he said "you know, we should show a bad one too" so we did that. I think the [vacuum] sound and the speed that the slide comes down are the two most important things. Those things you can't describe to someone really. I can't anyway. But it's absolutely the best way to verify that the diaphragm is seated properly.
  
 +
 +** Youtube Videos of:\\
 <font 16px/Arial, , ;;#​ffffff;;#​00FFF0>​ <font 16px/Arial, , ;;#​ffffff;;#​00FFF0>​
-[[http://​www.youtube.com/​watch?​v=L4knwjlNC1o|YouTube Video of GOOD working slide]]</​font>​ .........+[[http://​www.youtube.com/​watch?​v=L4knwjlNC1o|The Sound of GOOD working slide]]</​font>​ .........
 <font 16px/Arial, , ;;#​ffffff;;#​FFFF00>​ <font 16px/Arial, , ;;#​ffffff;;#​FFFF00>​
-[[http://​www.youtube.com/​watch?​v=k1YOkoekIeA|YouTube Video of MALFUNCTIONING slide]]</​font>​\\+[[http://​www.youtube.com/​watch?​v=k1YOkoekIeA|The Sound of MALFUNCTIONING slide]]</​font>​**
  
  
Line 100: Line 102:
 {{  :​techtalk:​evo:​carb:​cv40-needle-em-jets.jpg?​360| Photo by IXL2Relax at the XLForum}} {{  :​techtalk:​evo:​carb:​cv40-needle-em-jets.jpg?​360| Photo by IXL2Relax at the XLForum}}
 The "​DynoJet"​ kits (and many equivalent ones) can be an issue. Typically, they replace the factory needle, emulsion tube, main jet & diaphragm/​slide spring. They also recommend that you drill the slide vacuum hole out for quicker throttle response. The DynoJet emulsion tube and main jets are not compatible with the Keihin emulsion tube/jets - they use different threads. There are even FAKE Dynojet kits that have shown up on the market, presumably from China ((Fake DJ Kit - https://​www.dynojet.com/​warnings/​PressReleaseKnockOffJetKits.pdf)) The "​DynoJet"​ kits (and many equivalent ones) can be an issue. Typically, they replace the factory needle, emulsion tube, main jet & diaphragm/​slide spring. They also recommend that you drill the slide vacuum hole out for quicker throttle response. The DynoJet emulsion tube and main jets are not compatible with the Keihin emulsion tube/jets - they use different threads. There are even FAKE Dynojet kits that have shown up on the market, presumably from China ((Fake DJ Kit - https://​www.dynojet.com/​warnings/​PressReleaseKnockOffJetKits.pdf))
 +
 +More info & links here: [[:​techtalk:​evo:​carb02c|SubDoc - Why Not Dynojet Kits?]]
  
 **__To check for DynoJet parts, look at these 4 things:__** ((Identify DJ vs Keihin - http://​xlforum.net/​forums/​showpost.php?​p=5238545)) **__To check for DynoJet parts, look at these 4 things:__** ((Identify DJ vs Keihin - http://​xlforum.net/​forums/​showpost.php?​p=5238545))
Line 107: Line 111:
   * Check the Main Emulsion Tube : Stock has 2x2Hi+4x3Lo Emulsion Holes - DJ uses only 2Lo Holes   * Check the Main Emulsion Tube : Stock has 2x2Hi+4x3Lo Emulsion Holes - DJ uses only 2Lo Holes
 {{  :​techtalk:​evo:​carb:​cv40-needle-jet.jpg?​200| Annotated by IXL2Relax at the XLForum}} {{  :​techtalk:​evo:​carb:​cv40-needle-jet.jpg?​200| Annotated by IXL2Relax at the XLForum}}
-  * The stock Keihin Emulsion Tube uses 6mm Main Jets - The DJ one takes only 5mm jets, which are incompatible with the Keihin tube and only available from DJ+  * The stock Keihin Emulsion Tube uses 6mm-threaded ​Main Jets - The DJ one takes only 5mm-threaded ​jets, which are incompatible with the Keihin tube and only available from DJ
  
 Here's the Dynojet Fraud Alert Press Release regarding counterfeit jet kits:\\ Here's the Dynojet Fraud Alert Press Release regarding counterfeit jet kits:\\
 {{ :​techtalk:​evo:​carb:​dynojet-pressrelease-knockoffjetkits.pdf |}} {{ :​techtalk:​evo:​carb:​dynojet-pressrelease-knockoffjetkits.pdf |}}
  
-While some people have had satisfactory results with the DJ kits, if you are having trouble getting a good tune on the carb, remove all DJ items and restore the carb to Keihin parts including buying another slide if it's been drilled. The stock parts are good quality and will provide excellent operation if the carb is tuned properly. ((the opinion of many on the XLForum))+While some people have had satisfactory results with the DJ kits, if you are having trouble getting a good tune on the carb, remove all DJ items and restore the carb to Keihin parts including buying another slide if it's been drilled. The stock parts are good quality and will provide excellent operation if the carb is tuned properly. ((the opinion of many on the XLForum)) ​See the paragraphs above about 'Some Tuning Considerations'​.
  
-More info & links here: [[:​techtalk:​evo:​carb02c|SubDoc - Why Not Dynojet Kits?]]+\\
  
 From the factory, there is a cap over the Idle Mixture Screw. This needs to be removed to make IMS adjustments during tuning. It does not need to be replaced when done, but the cap is available as HD P/N 28015-01 if you would like to replace it when done making changes.((IMS Cap - http://​xlforum.net/​forums/​showpost.php?​p=595622&​postcount=9)) From the factory, there is a cap over the Idle Mixture Screw. This needs to be removed to make IMS adjustments during tuning. It does not need to be replaced when done, but the cap is available as HD P/N 28015-01 if you would like to replace it when done making changes.((IMS Cap - http://​xlforum.net/​forums/​showpost.php?​p=595622&​postcount=9))
Line 216: Line 220:
   * Check IMS seat (Has the screw needle tip deformed the hole?)   * Check IMS seat (Has the screw needle tip deformed the hole?)
   * Set initial IMS to 2-1/2 turns out from lite seat   * Set initial IMS to 2-1/2 turns out from lite seat
 +
 +==== Inspecting Float Level - Carb Installed ====
 + 
 +HD advised of a tip for adjusting the float level thru Tech Tip #36 dated September 1993. \\
 +However, this only works if you have an overflow fitting on the bowl (carbs for 1200S models don't have this fitting). \\ 
 +  * Checking carburetor float level can be easily done without even removing the carburetor from the motorcycle.
 +  * Simply attach a section of clear model airplane fuel line to the float bowl overflow fitting.
 +  * Small diameter fuel line, which is compatible with gasoline, can be found in most hobby supply shops.
 +  * Route the hose upward alongside the carburetor body. The motorcycle must be held level and be running to perform this test.
 +  * Open the float bowl drain screw and fuel will rise in the tube to the same level as that in the bowl itself.
 +  * A carburetor with a properly adjusted float level will have the level the same height as the float bowl 0-ring surface.
  
 \\ \\
Line 309: Line 324:
 **Main Jet** - The Main Jet itself does not begin to limit fuel delivery to the carb operation until the vacuum slide is 75-90% wide open and the engine is revving. Until then, other parts & factors (such as the idle mixture screw, slow-jet and needle position in the needle jet) are controlling the fuel utilized by the carb. **Main Jet** - The Main Jet itself does not begin to limit fuel delivery to the carb operation until the vacuum slide is 75-90% wide open and the engine is revving. Until then, other parts & factors (such as the idle mixture screw, slow-jet and needle position in the needle jet) are controlling the fuel utilized by the carb.
  
-**Needle & Needle Jet** - The needle is a tapered, nail-like, rod that operates from the bottom of the slide into the needle jet. It does not affect the flow of fuel until the throttle plate opens sufficiently to create an active vacuum in the outer section of the venturi, which will lift the slide and move the needle in the needle jet. The fuel mix supplied thru the needle jet, by your selected needle and the emulsion tube, will combine with the transfer fuel mix of the slow jet as the carb operation moves out of the transfer period into the mid-range of the throttle/​slide function.\\ The main jet, located at the bottom of the emulsion tube, is way below where the needle rides and has no relationship with what the needle does other than to create an eventual upper fuel limit at WOT. ((wedge of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1820463&​page=9)) The needle rides in the needle jet which is the silver jet (hollow cylinder) that sticks up from the bottom of the throat of the carb and the needle moves up and down thru it during operation.\\ The tapered needle and needle jet together control fuel flow coming out of the emulsion tube into the throat. After the needle is almost up and out of the needle jet, then the main jet will become the limiting factor for the fuel flow at the wide open throttle position (WOT). Until the needle gets out of the way, the main jet is doing nothing to limit the needed fuel.\\ ( See this [[http://​xlforum.net/​forums/​showthread.php?​t=165259|XLForum Thread]] on needle dimensions)+**Needle & Needle Jet** - The needle is a tapered, nail-like, rod that operates from the bottom of the slide into the needle jet. It does not affect the flow of fuel until the throttle plate opens sufficiently to create an active vacuum in the outer section of the venturi, which will lift the slide and move the needle in the needle jet. The fuel mix supplied thru the needle jet, by your selected needle and the emulsion tube, will combine with the transfer fuel mix of the slow jet as the carb operation moves out of the transfer period into the mid-range of the throttle/​slide function. 
 + 
 +The main jet, located at the bottom of the emulsion tube, is way below where the needle rides and has no relationship with what the needle does other than to create an eventual upper fuel limit at WOT. ((wedge of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=1820463&​page=9)) The needle rides in the needle jet which is the silver jet (hollow cylinder) that sticks up from the bottom of the throat of the carb and the needle moves up and down thru it during operation. 
 + 
 +The tapered needle and needle jet together control fuel flow coming out of the emulsion tube into the throat. After the needle is almost up and out of the needle jet, then the main jet will become the limiting factor for the fuel flow at the wide open throttle position (WOT). Until the needle gets out of the way, the main jet is doing nothing to limit the needed fuel. 
 + 
 +( See this [[http://​xlforum.net/​forums/​showthread.php?​t=165259|XLForum Thread]] on needle dimensions)
  
 **Emulsion Tubes** ((stevo of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=2876)):​ - As the throttle plate is opened further the main circuit comes into play. Fuel enters the bottom of the emulsion tube thru the main jet. Air enters thru the main air bleed jet in the front of the carb. The air and fuel are mixed into an emulsion in the emulsion tube before it passes up the tube past the needle jet and needle into the carb venturi and down the intake chasing after (combining with) the idle circuit fuel. The size, number and position of the holes in the emulsion tube effect the fuel delivery. More holes = more air = leaner mixture. More holes at the top = leaner mixture at low speeds. More holes at the bottom = leaner mixture at high speeds. If you change emulsion tubes you need to use a compatible needle. It will also have an effect on the main jet size (at WOT) and quite often the pilot circuit thru the just-off-idle response. Needles, needle jet, emulsion tube (size, position and amount of holes), main air bleed size and main jet are all closely linked. Changing one can affect the others and all have an affect on the fuel delivery to differing amount at different throttle positions. **Emulsion Tubes** ((stevo of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=2876)):​ - As the throttle plate is opened further the main circuit comes into play. Fuel enters the bottom of the emulsion tube thru the main jet. Air enters thru the main air bleed jet in the front of the carb. The air and fuel are mixed into an emulsion in the emulsion tube before it passes up the tube past the needle jet and needle into the carb venturi and down the intake chasing after (combining with) the idle circuit fuel. The size, number and position of the holes in the emulsion tube effect the fuel delivery. More holes = more air = leaner mixture. More holes at the top = leaner mixture at low speeds. More holes at the bottom = leaner mixture at high speeds. If you change emulsion tubes you need to use a compatible needle. It will also have an effect on the main jet size (at WOT) and quite often the pilot circuit thru the just-off-idle response. Needles, needle jet, emulsion tube (size, position and amount of holes), main air bleed size and main jet are all closely linked. Changing one can affect the others and all have an affect on the fuel delivery to differing amount at different throttle positions.
  
  
-**Throttle Plate** - To assure the throttle plate is capable of closing completely, back out the idle set screw (on the side of the carb near the throttle cable cam) so that it is not limiting the closing of the throttle plate. Carefully loosen the two throttle plate mounting screws, slightly. After the throttle plate is fully closed and has centered itself in the venturi, retighten the two mounting screws (don't overtighten & strip the threads). Make sure the throttle plate rotates smoothly with the throttle cable cam. Set the position of the throttle plate, with the idle set screw, so that the bottom edge of the plate is closed just past the transfer port holes and is thus located between the single idle port hole and the multiple holes of the transfer ports. (If by chance, for any reason, you have the throttle plate completely off, be aware that there is right & wrong way to reinstall it. Be sure the plate is remounted with the right orientation because the top & bottom have an angled edge that needs to properly meet the carb venturi.)+**Throttle Plate** - To assure the throttle plate is capable of closing completely, back out the idle set screw (on the side of the carb near the throttle cable cam) so that it is not limiting the closing of the throttle plate. Carefully loosen the two throttle plate mounting screws, slightly. After the throttle plate is fully closed and has centered itself in the venturi, retighten the two mounting screws (don't overtighten & strip the threads). Make sure the throttle plate rotates smoothly with the throttle cable cam. Set the position of the throttle plate, with the idle set screw, so that the bottom edge of the plate is closed just past the transfer port holes and is thus located between the single idle port hole and the multiple holes of the transfer ports. ​In practice, this is easier on some CV40 carbs than others. Do what you can to keep the plate as closed as possible, but don't obssess on getting it exactly between those port holes. Your viewing angle is skewed when looking in there, anyway. 
 + 
 +(If by chance, for any reason, you have the throttle plate completely off, be aware that there is right & wrong way to reinstall it. Be sure the plate is remounted with the right orientation because the top & bottom have an angled edge that needs to properly meet the carb venturi.)
  
 {{ :​techtalk:​evo:​carb:​cv40-imscap-drillbit.jpg?​200|}} {{ :​techtalk:​evo:​carb:​cv40-imscap-drillbit.jpg?​200|}}
Line 346: Line 369:
  
  
-At this point, we need the engine to be warmed up to normal operating temperature to continue tuning the carb. A cold engine may operate quite differently once warmed up, therefore, tuning the carb while the engine is cold is not valid. Since we set the idle screw very low, you may need to use the throttle or enrichener to keep the bike running...+At this point, we need the engine to be warmed up to normal operating temperature to continue tuning the carb. A cold engine may operate quite differently once warmed up, therefore, tuning the carb while the engine is cold is not valid.
  
-Start the engine and use the enrichener for the first 1-3 minutes ​while you take the bike for a 10-15 minute ride to warm the engine fully. Then be careful of the burn potential while working around a hot engine. Make sure you have no intake leaks in the manifold seals by using an unlit propane torch to flow propane around those seals. The engine idle will alter if an intake leak allows propane into the manifold.+Start the engine and use the enrichener ​if the engine is cold, for the first minute or so, while you take the bike for a 10-15 minute ride to warm the engine fully. Then be careful of the burn potential while working around a hot engine. Make sure you have no intake leaks in the manifold seals by using an unlit propane torch to flow propane around those seals. The engine idle will alter if an intake leak allows propane into the manifold.
  
 ==== The Idle Drop Method (IDM) ==== ==== The Idle Drop Method (IDM) ====
Line 354: Line 377:
 The Idle Drop Method (IDM) will help find the right setting for the Idle Mixture Screw (IMS)((see the chrishajer thread link below)). At idle, the engine will have difficulty if the idle fuel mix is too lean or if the idle fuel mix is too rich. There is a small range between those excesses, which is the point of this adjustment. This procedure does require the correct Slow Jet, so you may need to change the Slow Jet if you cannot find the described idle range while performing the IDM. The Idle Drop Method (IDM) will help find the right setting for the Idle Mixture Screw (IMS)((see the chrishajer thread link below)). At idle, the engine will have difficulty if the idle fuel mix is too lean or if the idle fuel mix is too rich. There is a small range between those excesses, which is the point of this adjustment. This procedure does require the correct Slow Jet, so you may need to change the Slow Jet if you cannot find the described idle range while performing the IDM.
  
-With the engine ​idling, set the idle speed as low as the possible ​for smooth engine operation. Lock the idle speed with the throttle grip lock rather than changing the setting of the Idle Set Screw (which should still be between the Idle Port & the Transfer Ports).+If you have previously set the throttle plate, between the idle port and the transfer ports, using the Idle Set Screw, you may need to roll the throttle slightly to keep the engine ​idle. With the throttle grip, set the idle speed as low as possible, yet still smooth engine operation. Lock the idle speed with the throttle grip lock (rather than changing the setting of the Idle Set Screwwhich should still be between the Idle Port & the Transfer Ports). 
 + 
 +Now carefully reach under the carb and adjust the IMS with very small increments, turning it counter-clockwise (as if looking up from below). This is enrichening the fuel mix. Listen for the engine speed to begin faltering, then STOP adjusting the screw. Now begin turning the IMS clockwise with very small movements. Listen for the engine speed to return to running well and then begin faltering as you continue to turn the screw clockwise, which will create a lean condition. When it falters, STOP adjusting the screw. 
 + 
 +Do this several times to be sure of your results and to calculate the amount of movment in 1/8 turn increments (1/2 of a 1/4 turn = 1/8 turn) that represents this range, from too rich to too lean. 
  
-Now carefully reach under the carb and adjust the IMS in very small increments, turning it counter-clockwise (as if looking up from below)This is enrichening the fuel mixListen for the engine speed to begin falteringSTOP adjusting the screwNow begin turning ​the IMS clockwise in very small movements. Calculate ​the amount ​of movment in 1/8 turn increments ​(1/2 of a 1/4 turn = 1/8 turn)Listen for the engine speed to begin faltering due to a lean condition. STOP adjusting ​the screw.+| **Note ​Trouble Finding A Change** - If you can't find a fall off until below 1/2 turn out, you need a smaller Slow JetIf you can't find a fall off in idle until beyond 3-1/2 turns out, you need a larger Slow JetIf the IMS setting appears ​to make no difference, you may have other issuesYou may have an intake leak or exhaust leakYou may have fuel leaking into the carb thru the vacuum hose because ​of a defective petcock diaphragm or thru a defective Accelerator Pump diaphragm.((oldboy at Post#7 - http://xlforum.net/forums/​showthread.php?​t=2076811)) Or, you may have the throttle plate too far open, thereby running on the Transfer Ports instead of the Idle Port|
  
-(Note: If you can't find a fall off until below 1/2 turn out, you need a smaller Slow Jet. If you can't find a fall off in idle until beyond 3-1/2 turns out, you need a larger Slow Jet.) 
  
-Now, use the counting you made (of the number of 1/8 turns) in order to make a setting of the IMS in the near center of the range you moved the screw from TOO RICH to TOO LEAN. For instance, if after finding the TOO RICH (CCW) setting, you then counted turning the screw SIX 1/8 turns (going CW) when you found the TOO LEAN condition, you would NOW turn the screw back (CCW) THREE 1/8 turns in order for it to be in the center of the range that operated well.+**Once you have found the range,** use the counting you made (of the number of 1/8 turns) in order to make a setting of the IMS in the near center of the range you moved the screw from TOO RICH to TOO LEAN. For instance, if after finding the TOO RICH (CCW) setting, you then counted turning the screw SIX 1/8 turns (going CW) when you found the TOO LEAN condition, you would NOW turn the screw back (CCW) THREE 1/8 turns in order for it to be in the center of the range that operated well.
  
 You can try this several times to assure yourself that you found the TOO RICH condition (CCW), then found the TOO LEAN condition (CW) and then were able to set the IMS (CCW) at the center between those. If the idle increases significantly during the adjustment, turn the throttle down to lower the RPMs and do the check again. You can try this several times to assure yourself that you found the TOO RICH condition (CCW), then found the TOO LEAN condition (CW) and then were able to set the IMS (CCW) at the center between those. If the idle increases significantly during the adjustment, turn the throttle down to lower the RPMs and do the check again.
Line 366: Line 393:
 The goal is to have the engine properly idle from the Slow Jet & the Idle Mixture Screw rather than by opening the throttle plate with the Idle Set Screw or throttle grip. Once you are satisfied that you did find the proper setting, you can turn the bike off. The goal is to have the engine properly idle from the Slow Jet & the Idle Mixture Screw rather than by opening the throttle plate with the Idle Set Screw or throttle grip. Once you are satisfied that you did find the proper setting, you can turn the bike off.
  
-Now check to see how many turns you must go (clockwise) until you GENTLY seat (closed) the IMS. WRITE DOWN THIS SETTING. That's it - You completed the Idle Mixture Screw setting using the Idle Drop Method.+Now check to see how many turns you must go (clockwise) until you GENTLY seat (closed) the IMS. **__WRITE ​DOWN THIS SETTING.__** Now put the IMS back to where it belongs. That's it - You completed the Idle Mixture Screw setting using the Idle Drop Method.
  
-You can now release the throttle lock. Start the engine & adjust the Idle Set Screw (it should require very little adjustment) for the proper idle speed, typically, between 950 & 1050 RPMs.+You can now release the throttle lock. Start the engine & adjust the Idle Set Screw (it should require very little adjustment) for the proper idle speed, typically, ​it should be set between 950 & 1050 RPMs.
  
 If you blip the throttle a few times, the engine should respond crisply. If you roll the throttle open, it should respond smoothly, increasing the RPMs without hesitation. If you blip the throttle a few times, the engine should respond crisply. If you roll the throttle open, it should respond smoothly, increasing the RPMs without hesitation.
Line 393: Line 420:
 **Some considerations:​** **Some considerations:​**
  
-A) Even when tuned correctly, cold engines are more likely to have carb farts than after they warm up. It is easier to create a lean condition when you open the throttle and gulp a large amount of cold air. If you ride off while the engine is still cold, expect to have farts. When the outside temperature is cold, you may also notice more carb farts for a longer period for the same reason. Trying to set your tune to eliminate carb farts that occur under cold conditions is likely to lead to excess fueling. ​Be sure to warm up the engine.+A) Even when tuned correctly, cold engines are more likely to have carb farts than after they warm up. It is easier to create a lean condition when you open the throttle and gulp a large amount of cold air. If you ride off while the engine is still cold, expect to have farts. When the outside temperature is cold, you may also notice more carb farts for a longer period for the same reason. Trying to set your tune to eliminate carb farts that occur under cold conditions is likely to lead to excess fueling. ​Instead, be sure to fully warm up the engine ​before tuning.
  
 B) You __should__ need the enrichener to start a cold engine. If you don't need it, your carb settings are too rich from the start. Go back to the general tuning stage and get this corrected before looking at carb farts. You may not have carb farts if you are that rich (which is not a good solution). B) You __should__ need the enrichener to start a cold engine. If you don't need it, your carb settings are too rich from the start. Go back to the general tuning stage and get this corrected before looking at carb farts. You may not have carb farts if you are that rich (which is not a good solution).
  
-C) HD added an Accelerator Pump on the CV40 in 1989 to help minimize carb farts by squirting extra fuel into the carb when you first twist the throttle. However, the EPA settings on the carb create a general lean condition which tends to increase the problem. This is another reason to do a proper tune on the carb, getting the overall Air-Fuel-Ratio (AFR) right, before addressing carb farts. Be sure the Accerator Pump is squirting a good spray into the carb, directed at the needle.+C) HD added an Accelerator Pump on the CV40 in 1989 to help minimize carb farts by squirting extra fuel into the carb when you first twist the throttle. However, the EPA settings on the carb create a general lean condition which tends to increase the problem. This is another reason to do a proper tune on the carb, getting the overall Air-Fuel-Ratio (AFR) right, before addressing carb farts. Be sure the Accerator Pump is squirting a good spray into the carb, directed at the needle ​to break up the stream into a spray.
  
 Every carb and engine is slightly different. Pay close attention to when & how you are getting carb farts. Use a thorough and patient approach to finding where the problem is located and choosing the right solution. Every carb and engine is slightly different. Pay close attention to when & how you are getting carb farts. Use a thorough and patient approach to finding where the problem is located and choosing the right solution.