{"product_id":"marine-contact-set-points-for-gm-4-cylinder-single-point-ignition-replaces-mercruiser-34235-omc-380538-sierra-18-5311","title":"Sierra 18-5311 Contact Set for Mercruiser 110, 120, 140, 2.5L, 3.0L I\/O Engines - Replaces Mercruiser 34235","description":"\u003cp\u003eThe Sierra 18-5311 is a marine ignition contact set (breaker points) built for contact-controlled distributor ignition systems on Mercruiser stern drive engines, standard rotation, excluding Thunderbolt ignition. It is the correct contact set for the Mercruiser 110, 120, and 140 models, as well as the 2.5L and 3.0L L4 engines, matching the tune-up kit and distributor components used across these engine families. As the wear item that opens and closes the primary ignition circuit inside the distributor, the contact set directly affects spark timing and engine starting reliability, so it is a standard replacement during a tune-up or when points become pitted, worn, or out of adjustment.\u003c\/p\u003e\u003cp\u003eConstructed with a glass-reinforced base and finished in white, the 18-5311 is built to meet or exceed original equipment quality so it drops into the distributor housing in place of the factory points without modification. It is sold as a single contact set (quantity of 1) and is intended to be paired with the matching rotor, distributor cap, coil, and spark plug wires for a complete tune-up on these applications.\u003c\/p\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Sierra\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number:\u003c\/strong\u003e 18-5311\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Ignition Contact Set\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Glass\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eColor:\u003c\/strong\u003e White\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.06 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC:\u003c\/strong\u003e 030999236609\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUnit Count:\u003c\/strong\u003e 1\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIgnition Type:\u003c\/strong\u003e Contact-controlled distributor, standard rotation, excludes Thunderbolt ignition\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFitment:\u003c\/strong\u003e Mercruiser 110, 120, 140 (153\/181 cid L4), 2.5L, and 3.0L L4 I\/O engines\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Cross-Reference:\u003c\/strong\u003e Chris-Craft 16.69-00049; GLM 70020; Mallory 9-29006; Mercruiser 34235, 34235T, 35637; OMC 380538\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eMercruiser 110 (153 cid\/L4), model years 1963-1966, serial numbers 1537370-2044033\u003c\/li\u003e\n\u003cli\u003eMercruiser 120 (153 cid\/L4), model years 1964-1986, serial numbers 1666601-B531853\u003c\/li\u003e\n\u003cli\u003eMercruiser 2.5L (153 cid\/L4), model years 1987-1989, serial numbers B531854-C853255\u003c\/li\u003e\n\u003cli\u003eMercruiser 140 (181 cid\/L4), model years 1968-1986, serial numbers 2508261-B450800\u003c\/li\u003e\n\u003cli\u003eMercruiser 3.0L (181 cid\/L4), model years 1987-1989, serial numbers B450801-C856558\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eChris-Craft 16.69-00049\u003c\/li\u003e\n\u003cli\u003eGLM 70020\u003c\/li\u003e\n\u003cli\u003eMallory 9-29006\u003c\/li\u003e\n\u003cli\u003eMercruiser 34235\u003c\/li\u003e\n\u003cli\u003eMercruiser 34235T\u003c\/li\u003e\n\u003cli\u003eMercruiser 35637\u003c\/li\u003e\n\u003cli\u003eOMC 380538\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat engines does the Sierra 18-5311 contact set fit?\u003c\/strong\u003e The 18-5311 fits Mercruiser 110 (1963-1966), 120 (1964-1986), 140 (1968-1986), 2.5L (1987-1989), and 3.0L (1987-1989) I\/O engines, all 153 or 181 cid L4 models using a contact-controlled distributor with standard rotation (not Thunderbolt ignition).\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs 18-5311 the same as Mercruiser part 34235?\u003c\/strong\u003e Yes, Sierra 18-5311 is a direct equivalent to Mercruiser 34235 and 34235T, as well as Chris-Craft 16.69-00049, GLM 70020, Mallory 9-29006, Mercruiser 35637, and OMC 380538.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the 18-5311 contact set weigh?\u003c\/strong\u003e The Sierra 18-5311 contact set weighs 0.06 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the contact set made of?\u003c\/strong\u003e The 18-5311 contact set uses a glass-reinforced base finished in white, matching the color and construction of the original equipment contact points.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes this contact set work with Thunderbolt ignition systems?\u003c\/strong\u003e No, the 18-5311 is designed for contact-controlled distributor systems with standard rotation and specifically excludes Thunderbolt ignition applications.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat comes in the box with the 18-5311?\u003c\/strong\u003e Each order includes one Sierra 18-5311 contact set, sold as a single unit count of 1.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDo I need to replace other ignition parts along with the contact set?\u003c\/strong\u003e For a complete tune-up on Mercruiser 110, 120, 140, 2.5L, or 3.0L engines, the contact set is typically replaced along with the matching rotor, distributor cap, coil, and spark plug wires for that model.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs Sierra 18-5311 an OEM or aftermarket part?\u003c\/strong\u003e The 18-5311 is an aftermarket replacement built to meet or exceed original equipment quality, cross-referencing directly to OEM numbers like Mercruiser 34235 and OMC 380538.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill 18-5311 fit a Mercruiser 3.0L from 1990 or later?\u003c\/strong\u003e No, the 18-5311 contact set applies to the 3.0L 181\/L4 engine for model years 1987-1989; later 3.0L serial ranges use a different contact set.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat color is the 18-5311 contact set?\u003c\/strong\u003e The Sierra 18-5311 contact set is white.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow do I know if my contact set needs replacing?\u003c\/strong\u003e Pitted, burned, or misadjusted contact points on the distributor commonly cause hard starting or rough idle, and replacing the 18-5311 contact set is the standard fix during a tune-up on these Mercruiser applications.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988208791771,"sku":"SIE-18-5311","price":12.02,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/SIE-18-5311_lg__86309.1558128338.500.750.jpg?v=1785189098","url":"https:\/\/www.goodvibesmarina.com\/products\/marine-contact-set-points-for-gm-4-cylinder-single-point-ignition-replaces-mercruiser-34235-omc-380538-sierra-18-5311","provider":"Good Vibes Marina","version":"1.0","type":"link"}