{"id":19262,"date":"2025-10-28T10:02:46","date_gmt":"2025-10-28T10:02:46","guid":{"rendered":"https:\/\/krogragg.com\/?p=19262"},"modified":"2025-10-28T10:02:46","modified_gmt":"2025-10-28T10:02:46","slug":"how-to-replace-an-outboard-water-pump","status":"publish","type":"post","link":"https:\/\/krogragg.com\/?p=19262","title":{"rendered":"How to Replace an Outboard Water Pump"},"content":{"rendered":"<p>    How to Replace an Outboard Water Pump<br \/>\n \t<BR><br \/>\n<BR><\/BR><br \/>\n    <!-- no image --><br \/>\n \t<BR><br \/>\n<BR><\/BR><\/p>\n<div>\n<section class=\"hydra-container\">\n<div class=\"hydra-canvas\">\n\t\t\t\t\t<img data-recalc-dims=\"1\" fetchpriority=\"high\" decoding=\"async\" width=\"800\" height=\"600\" src=\"https:\/\/i0.wp.com\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-1-1024x768.jpg?resize=800%2C600&#038;ssl=1\" class=\"hydra-image disable-lazyload\" alt=\"Water pump for an outboard engine\" sizes=\"(max-width: 1400px) 100vw, 1400px\" srcset=\"https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-1-1024x768.jpg 1024w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-1-300x225.jpg 300w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-1-768x576.jpg 768w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-1-1536x1152.jpg 1536w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-1.jpg 2000w\">                <\/div><figcaption class=\"caption margin_top_xs full border_1 hydra-figcaption\">\n                <span class=\"hydra-image-caption\">An outboard engine\u2019s water pump is driven by the driveshaft. Here the author is shown sliding the water-pump housing into place.<\/span><br \/>\n                <span class=\"article_image_credit italic margin_right_xs\">John Tiger<\/span><\/p>\n<\/figcaption><\/section>\n<p><iframe id=\"wxuzj5efbz\" src=\"https:\/\/boatingmag.dragonforms.com\/wxuzj5efbz\" scrolling=\"no\" style=\"width:100%;height:165px;border:none;overflow:hidden;\"><\/iframe><\/p>\n<p>Salt, sand, and debris take their toll on your outboard\u2019s water-pump impeller, housing, and related parts. Despite many \u201cI\u2019ve never replaced the water pump\u201d stories, good preventative maintenance practice includes replacement of the pump and housing at regular intervals\u2014annually is best.<\/p>\n<p>Because every engine is different, these instructions are general. Buy a service manual, such as a Seloc manual, for your specific engine before attempting this job. Then budget an hour or so to remove the gear case, \u00adreplace the pump, then reinstall the gear case.<\/p>\n<p><strong>1.<\/strong> Disconnect the shift cable \u00adunder the engine cowl. It will be easy to see if your helper shifts the control as you watch the \u00adcable. There also might be a shift-rod connection to \u00adaddress. Most Mercury and \u00adYamaha engines have a shift-rod \u00adconnection in the gear case that slides apart; Johnson and Evinrude engines have a connection under the cowl. Many manufacturers specify that the unit be in forward gear or neutral or reverse, and stay there until you reinstall the lower unit. The specific procedure will be described in your\u00a0manual.<\/p>\n<p><strong>2<\/strong>. Next, make the unit as light to handle as you can. Remove the propeller and any planing plates. If your engine is larger (over 60 to 70 hp), the unit will be hefty. Be sure that you can tilt the engine high enough and you have room \u00adto extract the gear case and drive shaft from the outboard.<\/p>\n<section class=\"hydra-container\">\n<div class=\"hydra-canvas\">\n\t\t\t\t\t<img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"600\" src=\"https:\/\/i0.wp.com\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-2-1024x768.jpg?resize=800%2C600&#038;ssl=1\" class=\"hydra-image\" alt=\"Outboard on an engine stand\" sizes=\"(max-width: 1400px) 100vw, 1400px\" srcset=\"https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-2-1024x768.jpg 1024w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-2-300x225.jpg 300w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-2-768x576.jpg 768w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-2-1536x1152.jpg 1536w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-2.jpg 2000w\">                <\/div><figcaption class=\"caption margin_top_xs full border_1 hydra-figcaption\">\n                <span class=\"hydra-image-caption\">You\u2019ll need a stand or support for the gear case (aka leg or lower unit) once you have removed it. Smaller ones can be clamped into a bench vise, with wood pads on the jaws. Larger ones require a dedicated stand.<\/span><br \/>\n                <span class=\"article_image_credit italic margin_right_xs\">John Tiger<\/span><\/p>\n<\/figcaption><\/section>\n<p><strong>3<\/strong>. You\u2019ll need a stand to hold the gear case after it\u2019s off the outboard. A wooden stand can be fashioned and used again. Clamp smaller units in a vise by the skeg. Pad the jaws of the vise with wood to protect the finish.<\/p>\n<section class=\"hydra-container\">\n<div class=\"hydra-canvas\">\n\t\t\t\t\t<img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"600\" src=\"https:\/\/i0.wp.com\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-3-1024x768.jpg?resize=800%2C600&#038;ssl=1\" class=\"hydra-image\" alt=\"Various parts of an outboard water pump\" sizes=\"(max-width: 1400px) 100vw, 1400px\" srcset=\"https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-3-1024x768.jpg 1024w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-3-300x225.jpg 300w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-3-768x576.jpg 768w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-3-1536x1152.jpg 1536w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-3.jpg 2000w\">                <\/div><figcaption class=\"caption margin_top_xs full border_1 hydra-figcaption\">\n                <span class=\"hydra-image-caption\">Boaters commonly say that their engine \u201cneeds a new impeller.\u201d In actuality, an engine\u2019s cooling water pump includes many parts that should be replaced, including a wear plate, gaskets, O-rings and more. <\/span><br \/>\n                <span class=\"article_image_credit italic margin_right_xs\">John Tiger<\/span><\/p>\n<\/figcaption><\/section>\n<p><strong>4<\/strong>. Typically, there are two or three bolts securing the lower unit on each side of the engine. There also might be a bolt in the front. Usually there is at least one or two hidden fasteners under the antiventilation plate. Before you completely remove that last bolt or nut, prepare yourself to catch the gear case in case it drops right out.<\/p>\n<p><strong>5<\/strong>. Carefully pull the unit down and away from the engine. You might have to coax it with some careful wiggling and prying. \u201cChoice words\u201d sometimes get voiced at this stage.<\/p>\n<section class=\"hydra-container\">\n<div class=\"hydra-canvas\">\n\t\t\t\t\t<img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"600\" src=\"https:\/\/i0.wp.com\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-4-1024x768.jpg?resize=800%2C600&#038;ssl=1\" class=\"hydra-image\" alt=\"Water pump's impeller\" sizes=\"(max-width: 1400px) 100vw, 1400px\" srcset=\"https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-4-1024x768.jpg 1024w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-4-300x225.jpg 300w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-4-768x576.jpg 768w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-4-1536x1152.jpg 1536w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-4.jpg 2000w\">                <\/div><figcaption class=\"caption margin_top_xs full border_1 hydra-figcaption\">\n                <span class=\"hydra-image-caption\">The impeller is the heart of the water pump. Its vanes push \u00adcooling water through the system to maintain the engine\u2019s operating temperature.<\/span><br \/>\n                <span class=\"article_image_credit italic margin_right_xs\">John Tiger<\/span><\/p>\n<\/figcaption><\/section>\n<p><strong>6<\/strong>. Use compressed air to clear debris from the intake passages and the area surrounding the pump. After removing the pump and the impeller plate, use the extended air-gun tip to reach down into the intake passages and blow out any accumulated silt. Blow compressed air up into the brass water tube in the engine midsection to clear any \u00addebris. Pull the impeller up and off the driveshaft, and remove the old Woodruff key, which should be replaced by a new one.<\/p>\n<section class=\"hydra-container\">\n<div class=\"hydra-canvas\">\n\t\t\t\t\t<img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"600\" src=\"https:\/\/i0.wp.com\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-5-1024x768.jpg?resize=800%2C600&#038;ssl=1\" class=\"hydra-image\" alt=\"Pushing impeller into water-pump housing\" sizes=\"(max-width: 1400px) 100vw, 1400px\" srcset=\"https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-5-1024x768.jpg 1024w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-5-300x225.jpg 300w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-5-768x576.jpg 768w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-5-1536x1152.jpg 1536w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-5.jpg 2000w\">                <\/div><figcaption class=\"caption margin_top_xs full border_1 hydra-figcaption\">\n                <span class=\"hydra-image-caption\">Here, we see the author about to fit the impeller into the water-pump housing. It\u2019s important that the impeller vanes are oriented the correct way: clockwise.<\/span><br \/>\n                <span class=\"article_image_credit italic margin_right_xs\">John Tiger<\/span><\/p>\n<\/figcaption><\/section>\n<p><strong>7<\/strong>. Install a new Woodruff key. When sliding the \u00adimpeller down the driveshaft, align the\u00a0slot in the impeller with\u00a0the Woodruff key. Be sure of \u00adproper impeller rotation, which is clockwise, then install the pump housing on top of the impeller while turning the driveshaft so that the vanes compress in the proper direction. Use a dab of engine oil on the impeller vanes of the impeller so that it\u2019s prelubricated upon startup of the engine. This also makes compressing the vanes easier.<\/p>\n<section class=\"hydra-container\">\n<div class=\"hydra-canvas\">\n\t\t\t\t\t<img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"600\" src=\"https:\/\/i0.wp.com\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-6-1024x768.jpg?resize=800%2C600&#038;ssl=1\" class=\"hydra-image\" alt=\"Applying sealant to the water-pump housing\" sizes=\"(max-width: 1400px) 100vw, 1400px\" srcset=\"https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-6-1024x768.jpg 1024w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-6-300x225.jpg 300w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-6-768x576.jpg 768w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-6-1536x1152.jpg 1536w, https:\/\/boatingmag.com\/wp-content\/uploads\/2025\/10\/BTG1025-Water-Pump-6.jpg 2000w\">                <\/div><figcaption class=\"caption margin_top_xs full border_1 hydra-figcaption\">\n                <span class=\"hydra-image-caption\">Applying the proper sealant.<\/span><br \/>\n                <span class=\"article_image_credit italic margin_right_xs\">John Tiger<\/span><\/p>\n<\/figcaption><\/section>\n<p><strong>8<\/strong>. Use any sealants called for by your engine\u2019s manual. Carefully tighten the housing screws. Do not overtorque, or you might crack the housing and cause a leak later, which could lead to overheating. This is also a great time to drain, check, and refill the gear \u00adlubricant.<\/p>\n<p><strong>9<\/strong>. Remember that the gear case must be in the correct gear before installation. Don\u2019t move the shift rod at all, or else you might have a hard time \u00adreinstalling the lower unit.<\/p>\n<p><strong>10<\/strong>. Clean the top of the driveshaft, then dab marine grease on the splines\u2014not on the top. Greasing the splines will make removal of the gear case easier next time. Be sure that the exhaust adapter is properly positioned in the midsection.<\/p>\n<p><strong>Read Next:<\/strong> <a href=\"https:\/\/boatingmag.com\/how-to-service-sterndrive-water-pump-impeller\/\">How to Service a Sterndrive Water Pump Impeller<\/a><\/p>\n<p><strong>11<\/strong>. While sliding the unit up into the midsection, ensure that the driveshaft, shift shaft and water tube are positioned properly. If you miss, the engine will not receive cooling water and will overheat, or it won\u2019t shift \u00adproperly and you\u2019ll have to \u00adremove and install it again.<\/p>\n<p><strong>12<\/strong>. After the installation is complete and you\u2019ve reconnected the shift shaft and shift cable, start the engine and ensure that it is pumping water, running properly at the proper temperature, and shifting from neutral to forward and to reverse correctly. <\/p>\n<p>The post <a rel=\"nofollow\" href=\"https:\/\/boatingmag.com\/how-to\/replacing-an-outboard-water-pump\/\">How to Replace an Outboard Water Pump<\/a> appeared first on <a rel=\"nofollow\" href=\"https:\/\/boatingmag.com\/\">Boating Mag<\/a>.<\/p>\n<\/div>\n<p> \t<BR><br \/>\n <BR><\/BR><br \/>\n    John Tiger<br \/>\n \t<BR><br \/>\n<BR><\/BR><br \/>\n<a href=\"https:\/\/boatingmag.com\/how-to\/replacing-an-outboard-water-pump\/\">Go to boatingmag<\/a><br \/>\n \t<BR><br \/>\n <BR><\/BR><\/p>\n","protected":false},"excerpt":{"rendered":"<p>How to Replace an Outboard Water Pump An outboard engine\u2019s water pump is driven by the driveshaft. Here the author is shown sliding the water-pump housing into place. John Tiger Salt, sand, and debris take their toll on your outboard\u2019s water-pump impeller, housing, and related parts. Despite many \u201cI\u2019ve never replaced the water pump\u201d stories, [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[178,126,179,175,6468,352],"tags":[127],"class_list":["post-19262","post","type-post","status-publish","format-standard","hentry","category-boat-maintenance","category-boatingmag","category-diy-projects","category-how-to","category-november-december-2025","category-outboards","tag-boatingmag"],"_links":{"self":[{"href":"https:\/\/krogragg.com\/index.php?rest_route=\/wp\/v2\/posts\/19262"}],"collection":[{"href":"https:\/\/krogragg.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/krogragg.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/krogragg.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/krogragg.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=19262"}],"version-history":[{"count":0,"href":"https:\/\/krogragg.com\/index.php?rest_route=\/wp\/v2\/posts\/19262\/revisions"}],"wp:attachment":[{"href":"https:\/\/krogragg.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=19262"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/krogragg.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=19262"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/krogragg.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=19262"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}