{"product_id":"sierra-18-1700-lower-unit-seal-kit-yamaha-60-70-hp","title":"Sierra 18-1700 Lower Unit Seal Kit, Yamaha 60-70 HP","description":"\u003cp class=\"nvn-hero\"\u003eThe Sierra 18-1700 lower unit seal kit reseals the gearcase on Yamaha 60-70 HP outboards in one complete set. You get the prop shaft and driveshaft seals, bearings, gaskets, and O-rings, all matched to meet or exceed the original parts. It's the cheap fix that keeps water out of your gear oil and saves the whole lower unit.\u003c\/p\u003e\n\n\u003cdiv class=\"nvn-description\"\u003e\n\u003cp\u003eWhen your Yamaha 60 or 70 HP outboard starts leaving a milky film on the dipstick, or you spot gear lube weeping past the prop shaft, it's almost always the lower unit seals letting go. This Sierra 18-1700 lower unit seal kit gives you everything you need to reseal the gearcase in one go. Seals, bearings, gaskets, and O-rings, all matched to fit Yamaha 60-70 HP engines.\u003c\/p\u003e\n\u003cp\u003eHere's the thing about lower unit seals. They're cheap. The damage they prevent isn't. A weeping prop shaft seal lets water sneak into the gearcase, and once saltwater mixes with your gear oil, the bearings and gears start to corrode. Catch it early with a fresh set of seals and you're looking at an afternoon of work. Ignore it and you're pricing out a whole lower unit. That's why we tell folks to pull the gearcase and pressure-test it every couple of seasons, especially if you run in salt.\u003c\/p\u003e\n\u003cp\u003eSierra builds this kit to meet or exceed the original equipment parts it replaces, so the fit and the sealing surfaces match what came off your engine. You get the seals that ride on the prop shaft and driveshaft, the bearings, the gaskets, and the O-rings that live in the housing grooves. One box, one part number, no hunting down individual seals by the piece.\u003c\/p\u003e\n\u003cp\u003eA few things worth knowing before you dive in. Seal orientation matters. A lot. The lower prop shaft seal has to face the right direction or water walks straight past it into the crankcase, and you'll be back in there in a week. Take a photo before you press the old ones out. Clean the housing grooves until they're spotless before you seat the new O-rings, because even a little old gasket material or debris will keep a seal from sitting flat and it'll leak under pressure.\u003c\/p\u003e\n\u003cp\u003eWhile you've got the lower unit off, look at the driveshaft splines. On older Yamahas the splines like to corrode, so wire-brush them clean and grease them before you slide the bearings and driveshaft back together. If the pump housing is scored or worn, replace it too, or the new seals won't have a clean surface to work against. And if you're this deep into the gearcase already, it's a smart time to drop in a fresh water pump impeller and key. Most folks running saltwater refresh the impeller every two to three seasons anyway, and doing it now saves you pulling the lower unit twice.\u003c\/p\u003e\n\u003cp\u003eFitment covers Yamaha 60 HP and 70 HP outboards. These engines ran across a lot of model years, and the bearing sizes on some of the 1990s blocks differ from the 2000s ones, so match the 18-1700 part number to your specific engine before you order. When in doubt, give us the year and model of your motor and we'll help you confirm it's the right kit before it ships, so you're not stuck mid-service with the wrong seals on the bench.\u003c\/p\u003e\n\u003cp\u003eReassembly is straightforward if you take your time. Use a proper seal driver so you don't cock a seal in its bore, seat everything square, and torque the housing bolts to the factory spec. That last part gets skipped more than it should. Under-torqued or uneven bolts warp the housing plate and you'll chase leaks all season. Do it right once and this reseal holds for years.\u003c\/p\u003e\n\u003cp\u003eFor a first-timer this is a very doable job with a manual, a seal driver, and a rainy Saturday. For a shop, it's routine. Either way, starting with a complete Sierra kit beats piecing seals together and hoping you got them all. Keep the old seals set aside until the job's buttoned up and the engine's run, just in case you want to double-check a size or an orientation against them.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul class=\"nvn-features\"\u003e\n  \u003cli\u003eComplete lower unit reseal in one box: seals, bearings, gaskets, and O-rings for Yamaha 60-70 HP outboards\u003c\/li\u003e\n  \u003cli\u003eSierra 18-1700 direct-fit kit meets or exceeds the original equipment parts it replaces\u003c\/li\u003e\n  \u003cli\u003eProp shaft and driveshaft seals keep gear oil in and water out of the gearcase\u003c\/li\u003e\n  \u003cli\u003eHousing O-rings and gaskets reseal the pressure surfaces so the case holds under load\u003c\/li\u003e\n  \u003cli\u003eFits both Yamaha 60 HP and 70 HP outboard engines\u003c\/li\u003e\n  \u003cli\u003eOne part number covers the full seal set, no piecing together individual seals\u003c\/li\u003e\n  \u003cli\u003eIdeal for a scheduled gearcase service or fixing a milky gear-oil leak\u003c\/li\u003e\n  \u003cli\u003ePairs well with a fresh water pump impeller and key while the lower unit is off\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cdiv class=\"nvn-trust\"\u003e\n  \u003ch2\u003eWhy Buy from NVN Marine\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eAuthorized Sierra Marine reseller, full manufacturer warranty\u003c\/li\u003e\n    \u003cli\u003eNMEA member and ABYC certified, advice from real boat techs\u003c\/li\u003e\n    \u003cli\u003eSame-day shipping before 3 PM ET on in-stock items\u003c\/li\u003e\n    \u003cli\u003eNY headquarters and Fort Lauderdale flagship retail store\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cdiv class=\"nvn-faq\"\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat engines does the Sierra 18-1700 seal kit fit?\u003c\/summary\u003e\n    \u003cp\u003eIt fits Yamaha 60 HP and 70 HP outboard engines. These motors ran across many model years, so match the 18-1700 part number to your specific engine and year before ordering, since some 1990s blocks use different bearing sizes than the 2000s ones.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat comes in the kit?\u003c\/summary\u003e\n    \u003cp\u003eThe kit includes the lower unit seals, bearings, gaskets, and O-rings needed to reseal the gearcase. It's a complete seal set for the job in one part number.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eDoes this kit include a water pump impeller?\u003c\/summary\u003e\n    \u003cp\u003eNo. This is a seal kit: seals, bearings, gaskets, and O-rings. If you're already pulling the lower unit, it's a good time to install a fresh water pump impeller and key at the same time, since most saltwater boaters refresh the impeller every two to three seasons anyway.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhy does seal orientation matter when I install these?\u003c\/summary\u003e\n    \u003cp\u003eThe lower prop shaft seal has to face the correct direction. Reverse it and water walks straight past the seal into the crankcase, causing an immediate leak. Take a photo of the old seals before you press them out so you can match the orientation.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow often should I replace the lower unit seals?\u003c\/summary\u003e\n    \u003cp\u003ePlan on a gearcase reseal every couple of seasons, more often if you run in saltwater. Pull the lower unit, pressure-test it, and replace the seals as part of routine service before a small weep turns into water in your gear oil.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat should I check before reassembling the lower unit?\u003c\/summary\u003e\n    \u003cp\u003eClean the housing O-ring grooves until they're free of any old gasket material or debris, or the new seals won't seat flat and will leak under pressure. Also inspect the driveshaft splines for corrosion, wire-brush them clean, and grease them before sliding the bearings back on.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eAre these OEM-quality parts?\u003c\/summary\u003e\n    \u003cp\u003eYes. Sierra engineers this kit to meet or exceed the original equipment part it replaces, so the sealing surfaces and fit match what came off your engine. Sierra supplies replacement parts to many OEM engine and boat builders.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eAny tips for a clean, long-lasting install?\u003c\/summary\u003e\n    \u003cp\u003eUse a proper seal driver so you don't cock a seal in its bore, seat everything square, and torque the housing bolts evenly to the factory spec. Uneven or under-torqued bolts warp the housing plate and lead to repeat leaks. If the pump housing is scored or worn, replace it too so the new seals have a clean surface to ride on.\u003c\/p\u003e\n  \u003c\/details\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003ctable class=\"nvn-specs\"\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003cth\u003eTitle\u003c\/th\u003e\n\u003ctd\u003eSierra 18-1700 Lower Unit Seal Kit\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003ctd\u003eSierra Marine\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eManufacturer Part Number\u003c\/th\u003e\n\u003ctd\u003e18-1700\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eUPC\u003c\/th\u003e\n\u003ctd\u003e808282383183\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eKit Type\u003c\/th\u003e\n\u003ctd\u003eLower Unit Seal Kit\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eApplication\u003c\/th\u003e\n\u003ctd\u003eLower unit \/ gearcase seal replacement\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eEngine Make\u003c\/th\u003e\n\u003ctd\u003eYamaha\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eEngine Horsepower Range\u003c\/th\u003e\n\u003ctd\u003e60-70 HP\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eFits Engines\u003c\/th\u003e\n\u003ctd\u003eYamaha 60-70 HP outboards\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eKit Contents\u003c\/th\u003e\n\u003ctd\u003eSeals, bearings, gaskets, and O-rings\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eIncludes Seals\u003c\/th\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eIncludes Bearings\u003c\/th\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eIncludes Gaskets\u003c\/th\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eIncludes O-Rings\u003c\/th\u003e\n\u003ctd\u003eYes\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eReplacement Standard\u003c\/th\u003e\n\u003ctd\u003eMeets or exceeds OEM specification\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e\n{\n    \"@context\": \"https:\/\/schema.org\",\n    \"@type\": \"FAQPage\",\n    \"mainEntity\": [\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What engines does the Sierra 18-1700 seal kit fit?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"It fits Yamaha 60 HP and 70 HP outboard engines. These motors ran across many model years, so match the 18-1700 part number to your specific engine and year before ordering, since some 1990s blocks use different bearing sizes than the 2000s ones.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What comes in the kit?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"The kit includes the lower unit seals, bearings, gaskets, and O-rings needed to reseal the gearcase. It's a complete seal set for the job in one part number.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Does this kit include a water pump impeller?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"No. This is a seal kit: seals, bearings, gaskets, and O-rings. If you're already pulling the lower unit, it's a good time to install a fresh water pump impeller and key at the same time, since most saltwater boaters refresh the impeller every two to three seasons anyway.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Why does seal orientation matter when I install these?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"The lower prop shaft seal has to face the correct direction. Reverse it and water walks straight past the seal into the crankcase, causing an immediate leak. Take a photo of the old seals before you press them out so you can match the orientation.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"How often should I replace the lower unit seals?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Plan on a gearcase reseal every couple of seasons, more often if you run in saltwater. Pull the lower unit, pressure-test it, and replace the seals as part of routine service before a small weep turns into water in your gear oil.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What should I check before reassembling the lower unit?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Clean the housing O-ring grooves until they're free of any old gasket material or debris, or the new seals won't seat flat and will leak under pressure. Also inspect the driveshaft splines for corrosion, wire-brush them clean, and grease them before sliding the bearings back on.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Are these OEM-quality parts?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Yes. Sierra engineers this kit to meet or exceed the original equipment part it replaces, so the sealing surfaces and fit match what came off your engine. Sierra supplies replacement parts to many OEM engine and boat builders.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Any tips for a clean, long-lasting install?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Use a proper seal driver so you don't cock a seal in its bore, seat everything square, and torque the housing bolts evenly to the factory spec. Uneven or under-torqued bolts warp the housing plate and lead to repeat leaks. If the pump housing is scored or worn, replace it too so the new seals have a clean surface to ride on.\"\n            }\n        }\n    ]\n}\n\u003c\/script\u003e\n","brand":"Sierra Marine","offers":[{"title":"Default Title","offer_id":45072558260317,"sku":"2009289","price":45.19,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0299\/7266\/0317\/files\/ImageServerAPI_c036438a-1d56-4766-819b-085c197482aa.png?v=1789751286","url":"https:\/\/nvnmarine.com\/products\/sierra-18-1700-lower-unit-seal-kit-yamaha-60-70-hp","provider":"NVN Marine","version":"1.0","type":"link"}