{"id":19540,"date":"2023-05-22T08:00:00","date_gmt":"2023-05-21T23:00:00","guid":{"rendered":"https:\/\/www.decoboco.info\/en\/?p=19540"},"modified":"2026-09-24T13:46:13","modified_gmt":"2026-09-24T04:46:13","slug":"pilot-screw-dramatically-improves-zephyr-550-400-startability","status":"publish","type":"post","link":"https:\/\/www.decoboco.info\/en\/20230522\/decoboco-cars\/zephyr550zr550\/pilot-screw-dramatically-improves-zephyr-550-400-startability","title":{"rendered":"Dramatically Improving Zephyr 550\/400 Startability with Pilot Screw Adjustment"},"content":{"rendered":"<div id=\"decob-2518500076\" class=\"decob- decob-entity-placement\"><a href=\"https:\/\/www.decoboco.info\/advertise\" aria-label=\"ad_sample_1456_180_1\"><img src=\"https:\/\/www.decoboco.info\/en\/wp-content\/uploads\/sites\/2\/2025\/04\/ad_sample_1456_180_1.png\" alt=\"\"  srcset=\"https:\/\/www.decoboco.info\/en\/wp-content\/uploads\/sites\/2\/2025\/04\/ad_sample_1456_180_1.png 1456w, https:\/\/www.decoboco.info\/en\/wp-content\/uploads\/sites\/2\/2025\/04\/ad_sample_1456_180_1-300x37.png 300w, https:\/\/www.decoboco.info\/en\/wp-content\/uploads\/sites\/2\/2025\/04\/ad_sample_1456_180_1-1024x127.png 1024w, https:\/\/www.decoboco.info\/en\/wp-content\/uploads\/sites\/2\/2025\/04\/ad_sample_1456_180_1-768x95.png 768w\" sizes=\"(max-width: 1456px) 100vw, 1456px\" width=\"812\" height=\"100\"   \/><\/a><\/div>\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" width=\"1024\" height=\"576\" src=\"https:\/\/www.decoboco.info\/wp-content\/uploads\/2023\/05\/3934ddc04f48b1e41070ea7354a4ea7b-1024x576.png\" alt=\"\" class=\"wp-image-19539\" srcset=\"https:\/\/www.decoboco.info\/en\/wp-content\/uploads\/sites\/2\/2023\/05\/3934ddc04f48b1e41070ea7354a4ea7b-1024x576.png 1024w, https:\/\/www.decoboco.info\/en\/wp-content\/uploads\/sites\/2\/2023\/05\/3934ddc04f48b1e41070ea7354a4ea7b-300x169.png 300w, https:\/\/www.decoboco.info\/en\/wp-content\/uploads\/sites\/2\/2023\/05\/3934ddc04f48b1e41070ea7354a4ea7b-768x432.png 768w, https:\/\/www.decoboco.info\/en\/wp-content\/uploads\/sites\/2\/2023\/05\/3934ddc04f48b1e41070ea7354a4ea7b-1200x675.png 1200w, https:\/\/www.decoboco.info\/en\/wp-content\/uploads\/sites\/2\/2023\/05\/3934ddc04f48b1e41070ea7354a4ea7b.png 1280w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<div style=\"height:100px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n<div class=\"swell-block-balloon\"><div class=\"c-balloon -bln-left\" data-col=\"gray\"><div class=\"c-balloon__body -speaking -border-none\"><div class=\"c-balloon__text\">\n<p><strong>&#8220;Pilot Screw Adjustment with Stock Carburetor&#8221;<\/strong><br>is quite effective.<\/p>\n<span class=\"c-balloon__shapes\"><span class=\"c-balloon__before\"><\/span><span class=\"c-balloon__after\"><\/span><\/span><\/div><\/div><\/div><\/div>\n\n\n<p class=\"has-text-align-center wp-block-paragraph\"><br><br>The service manual&#8217;s specified value<br>may not always be<br>the best for each individual unit.<br><br>It&#8217;s determined from various perspectives<br>such as exhaust emissions CO\/HC<br>with social and environmental considerations being quite high.<br><br>Simply adjusting to<br>the amount of fuel<br>the engine currently wants<br>often reveals<br>hidden performance potential.<\/p>\n\n\n\n<p class=\"has-text-align-center wp-block-paragraph\"><br><\/p>\n\n\n\n<div style=\"height:100px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<!--more-->\n\n\n\n<div style=\"height:100px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"has-text-align-center wp-block-paragraph\"><br><\/p>\n\n\n\n<figure class=\"wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<iframe title=\"\u59cb\u52d5\u6027\u300c\u6fc0\u5909\u300dZEPHYR550 ZR550 \u30bc\u30d5\u30a1\u30fc550\u4e2d\u53e4\u6574\u5099\u30d1\u30a4\u30ed\u30c3\u30c8\u30b9\u30af\u30ea\u30e5\u30fc\u8abf\u6574\u3000Used maintenance pilot screw adjustment\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/QvkCnVLGIg0?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe>\n<\/div><\/figure>\n\n\n\n<div style=\"height:100px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"has-text-align-center wp-block-paragraph\">I actually shot the video<br>before writing this blog post,<br>so please refer to it.<br>Currently,<\/p>\n\n\n<div class=\"swell-block-balloon\"><div class=\"c-balloon -bln-left\" data-col=\"gray\"><div class=\"c-balloon__body -speaking -border-none\"><div class=\"c-balloon__text\">\n<p><strong>&#8220;Churrrr!&#8221;<\/strong>and it starts beautifully.<\/p>\n<span class=\"c-balloon__shapes\"><span class=\"c-balloon__before\"><\/span><span class=\"c-balloon__after\"><\/span><\/span><\/div><\/div><\/div><\/div>\n\n\n<p class=\"has-text-align-center wp-block-paragraph\"><br><\/p>\n\n\n\n<div style=\"height:100px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"has-text-align-center wp-block-paragraph\">The manual specifies 2\u00b11\/4 turns<br>common to both Zephyr 400\/550.<br>Currently,<br>I have it set to<strong>&#8220;3-1\/2<\/strong>&#8221; turns open.<br><br>However, my model<br><strong>has a &#8220;secondary air reduction system&#8221;<\/strong><br>installed\u2014<br><br>in other words,<br>it cleans exhaust by leaning the mixture,<br>which also leans the fuel,<br>making both startability and response<br>extremely poor.<br><br>This Zephyr 400\/550<br>with CVK carburetor<\/p>\n\n\n<div class=\"swell-block-balloon\"><div class=\"c-balloon -bln-left\" data-col=\"gray\"><div class=\"c-balloon__body -speaking -border-none\"><div class=\"c-balloon__text\">\n<p>has the most difficult pilot screw adjustment<br>difficulty level number one!<\/p>\n<span class=\"c-balloon__shapes\"><span class=\"c-balloon__before\"><\/span><span class=\"c-balloon__after\"><\/span><\/span><\/div><\/div><\/div><\/div>\n\n\n<p class=\"has-text-align-center wp-block-paragraph\"><br><br><br>My favorite PS driver absolutely<br>won&#8217;t fit in the extremely tight clearance.<br><\/p>\n\n\n<div class=\"swell-block-balloon\"><div class=\"c-balloon -bln-left\" data-col=\"gray\"><div class=\"c-balloon__body -speaking -border-none\"><div class=\"c-balloon__text\">\n<p>Honestly,<br>it&#8217;s abnormally tight&#8230;<br>Since it&#8217;s based on the 400,<br>it can&#8217;t be helped.<\/p>\n<span class=\"c-balloon__shapes\"><span class=\"c-balloon__before\"><\/span><span class=\"c-balloon__after\"><\/span><\/span><\/div><\/div><\/div><\/div>\n\n\n<p class=\"has-text-align-center wp-block-paragraph\"><br><br>There are tools<br>that could be called Zephyr 400\/550 specific,<br>so please definitely get one!<\/p>\n\n\n<div class=\"swell-block-balloon\"><div class=\"c-balloon -bln-left\" data-col=\"gray\"><div class=\"c-balloon__body -speaking -border-none\"><div class=\"c-balloon__text\">\n<p>( *\u00b4\u8278\uff40) Go ahead and tinker with<br>the pilot screw.<br><a href=\"https:\/\/www.decoboco.info\/en\/?p=19537\">\u2462<strong>Ignition Improvement ZEPHYR 400\/550 Zephyr 550\/400 &#8220;NGK Plug Cap\/Silicon Plug Code Replacement Works Better Than Expected&#8221;<\/strong><\/a><\/p>\n<span class=\"c-balloon__shapes\"><span class=\"c-balloon__before\"><\/span><span class=\"c-balloon__after\"><\/span><\/span><\/div><\/div><\/div><\/div>\n\n\n<div style=\"height:100px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\t\t<div class=\"pochipp-box\"\n\t\t\tdata-id=\"346\"\n\t\t\tdata-img=\"l\"\n\t\t\tdata-lyt-pc=\"imgbig\"\n\t\t\tdata-lyt-mb=\"vrtcl\"\n\t\t\tdata-btn-style=\"dflt\"\n\t\t\tdata-btn-radius=\"on\"\n\t\t\tdata-sale-effect=\"flash\"\n\t\t\t data-cvkey=\"383609a2\"\t\t>\n\t\t\t\t\t\t\t<div class=\"pochipp-box__image\">\n\t\t\t\t\t<a href=\"https:\/\/af.moshimo.com\/af\/c\/click?a_id=3739420&#038;p_id=170&#038;pc_id=185&#038;pl_id=4062&#038;url=https%3A%2F%2Fwww.amazon.co.jp%2Fdp%2FB004J271L6\" rel=\"nofollow noopener\" target=\"_blank\">\n\t\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/m.media-amazon.com\/images\/I\/316jEesGFCL._SL500_.jpg\" alt=\"\" width=\"120\" height=\"120\" \/>\t\t\t\t\t<\/a>\n\t\t\t\t<\/div>\n\t\t\t\t\t\t<div class=\"pochipp-box__body\">\n\t\t\t\t<div class=\"pochipp-box__title\">\n\t\t\t\t\t<a href=\"https:\/\/af.moshimo.com\/af\/c\/click?a_id=3739420&#038;p_id=170&#038;pc_id=185&#038;pl_id=4062&#038;url=https%3A%2F%2Fwww.amazon.co.jp%2Fdp%2FB004J271L6\" rel=\"nofollow noopener\" target=\"_blank\">\n\t\t\t\t\t\tZephyr 400\/550 optimal pilot screw adjustment angled driver\t\t\t\t\t<\/a>\n\t\t\t\t<\/div>\n\n\t\t\t\t\t\t\t\t\t<div class=\"pochipp-box__info\">\u30a2\u30b9\u30c8\u30ed\u30d7\u30ed\u30c0\u30af\u30c4<\/div>\n\t\t\t\t\n\t\t\t\t\t\t\t\t\t<div class=\"pochipp-box__price\">\n\t\t\t\t\t\t\u00a57,469\t\t\t\t\t\t<span>\uff082026\/09\/21 17:35\u6642\u70b9 | Amazon\u8abf\u3079\uff09<\/span>\n\t\t\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\t\t\t\t\t<div class=\"pochipp-box__review\">\n\t\t\t\t\t\t<a href=\"https:\/\/af.moshimo.com\/af\/c\/click?a_id=3739420&amp;p_id=170&amp;pc_id=185&amp;pl_id=4062&amp;url=https%3A%2F%2Fwww.amazon.co.jp%2Fproduct-reviews%2FB004J271L6\" rel=\"nofollow noopener\" target=\"_blank\">\n\t\t\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.decoboco.info\/en\/wp-content\/plugins\/pochipp\/assets\/img\/review.svg\" alt=\"\" width=\"16\" height=\"16\" \/>\n\t\t\t\t\t\t\t<span>\u53e3\u30b3\u30df\u3092\u898b\u308b<\/span>\n\t\t\t\t\t\t<\/a>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"pochipp-box__btns\"\n\t\tdata-maxclmn-pc=\"fit\"\n\t\tdata-maxclmn-mb=\"1\"\n\t>\n\t\t\t\t\t<div class=\"pochipp-box__btnwrap -amazon\">\n\t\t\t\t\t\t\t\t<a href=\"https:\/\/af.moshimo.com\/af\/c\/click?a_id=3739420&#038;p_id=170&#038;pc_id=185&#038;pl_id=4062&#038;url=https%3A%2F%2Fwww.amazon.co.jp%2Fdp%2FB004J271L6\" class=\"pochipp-box__btn\" rel=\"nofollow noopener\" target=\"_blank\">\n\t\t\t\t\t<span>\n\t\t\t\t\t\tAmazon\t\t\t\t\t<\/span>\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/i.moshimo.com\/af\/i\/impression?a_id=3739420&#038;p_id=170&#038;pc_id=185&#038;pl_id=4062\" width=\"1\" height=\"1\" style=\"border:none;\">\t\t\t\t<\/a>\n\t\t\t<\/div>\n\t\t\t\t\t\t\t<div class=\"pochipp-box__btnwrap -rakuten\">\n\t\t\t\t\t\t\t\t<a href=\"https:\/\/af.moshimo.com\/af\/c\/click?a_id=3739418&#038;p_id=54&#038;pc_id=54&#038;pl_id=616&#038;url=https%3A%2F%2Fitem.rakuten.co.jp%2Fastroproducts-shop2%2F2007000007099%2F\" class=\"pochipp-box__btn\" rel=\"nofollow noopener\" target=\"_blank\">\n\t\t\t\t\t<span>\n\t\t\t\t\t\tRakuten\t\t\t\t\t<\/span>\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/i.moshimo.com\/af\/i\/impression?a_id=3739418&#038;p_id=54&#038;pc_id=54&#038;pl_id=616\" width=\"1\" height=\"1\" style=\"border:none;\">\t\t\t\t<\/a>\n\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t\t<div class=\"pochipp-box__btnwrap -yahoo\">\n\t\t\t\t\t\t\t\t<a href=\"https:\/\/af.moshimo.com\/af\/c\/click?a_id=3739424&#038;p_id=1225&#038;pc_id=1925&#038;pl_id=19142&#038;url=https%3A%2F%2Fstore.shopping.yahoo.co.jp%2Fastroproducts%2F2007000007099.html\" class=\"pochipp-box__btn\" rel=\"nofollow noopener\" target=\"_blank\">\n\t\t\t\t\t<span>\n\t\t\t\t\t\tYahoo!\t\t\t\t\t<\/span>\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/i.moshimo.com\/af\/i\/impression?a_id=3739424&#038;p_id=1225&#038;pc_id=1925&#038;pl_id=19142\" width=\"1\" height=\"1\" style=\"border:none;\">\t\t\t\t<\/a>\n\t\t\t<\/div>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t\t<div class=\"pochipp-box__logo\">\n\t\t\t\t\t<img decoding=\"async\" src=\"https:\/\/www.decoboco.info\/en\/wp-content\/plugins\/pochipp\/assets\/img\/pochipp-logo-t1.png\" alt=\"\" width=\"32\" height=\"32\">\n\t\t\t\t\t<span>\u30dd\u30c1\u30c3\u30d7<\/span>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t","protected":false},"excerpt":{"rendered":"<p>The service manual&#8217;s specified valuemay not always bethe best for each individual unit. It&#8217;s determined from various perspectivessuch as exhaust emissions CO\/HCwith social and environmental considerations being quite high. Simply adjusting tothe amount of fuelthe engine currently wantsoften revealshidden performance potential.<\/p>\n","protected":false},"author":2,"featured_media":19538,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"pochipp_cv_data":"{\"383609a2\":{\"pv\":5693,\"imp\":4211,\"clickedOther\":142,\"clickedAmazon\":77,\"clickedYahoo\":16,\"clickedRakuten\":16}}","swell_btn_cv_data":"","footnotes":""},"categories":[41],"tags":[607,601,612,613],"class_list":["post-19540","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-zephyr550zr550","tag-zephyr-400","tag-zephyr-550","tag-zephyr550","tag-zr550"],"_links":{"self":[{"href":"https:\/\/www.decoboco.info\/en\/wp-json\/wp\/v2\/posts\/19540","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.decoboco.info\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.decoboco.info\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.decoboco.info\/en\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.decoboco.info\/en\/wp-json\/wp\/v2\/comments?post=19540"}],"version-history":[{"count":0,"href":"https:\/\/www.decoboco.info\/en\/wp-json\/wp\/v2\/posts\/19540\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.decoboco.info\/en\/wp-json\/wp\/v2\/media\/19538"}],"wp:attachment":[{"href":"https:\/\/www.decoboco.info\/en\/wp-json\/wp\/v2\/media?parent=19540"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.decoboco.info\/en\/wp-json\/wp\/v2\/categories?post=19540"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.decoboco.info\/en\/wp-json\/wp\/v2\/tags?post=19540"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}