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  • Writer's pictureDave LeGear

Low budget Outboard Pre-Lube pump (4 Stroke only)

The reason Military and many other Industrial grade engines last so much longer (other than being built for such and run expensive lube oils) is that they employ a Pre-Lube pump to circulate lube oil throughout the engine before it is lit off / started. One of our long standing checklist items back when I was in the USCG and yes, this was well past the use of Cannon Balls and Sails for those calling me OLD! LOL... Was to bring online and make sure we had X amount of Oil PSI, before the crank was spun over a single degree. So, looking to employ such thinking on our past Yamaha F70 Outboard especially after an engine oil change... I discovered that "if" I left the red kill safety switch insert disconnected (unlike my past BF150 Honda) that I could spin the engine over for some time and it would not start.

This is great! and though not a true Pre-Lube pump by design..., It does allow one to spin the engine over and allow oil pressure to build up since the oil pump is a mechanical pump, before putting fire to any cylinder. As such, anytime I go to start the engine now... I leave the kill switch disconnected and spin her over for 5 to 10 seconds to build up oil pressure inside the Engine, before I then reach down and insert it for what I call the final "Light Off" Now will this help any? Well, much better than the engine going from setting (sometimes for days or longer) and starting right up with many components still dry, now under a full load, and getting hot real fast, than no oil at all... Also, a good practice after making an oil change and most all the new oil is just setting in the oil pan so you can move that fresh oil all around the engine some. I am sure some will say this could be hard on a Starter. If you stayed on the ignition switch for a real long period of time I might agree, and therefore I do it for such a short periods of time. And in the long run, I would much rather swap out a starter than having to rebuild the top end or entire engine any day! Again, you do not need to spin her over for a real long period of time... Now this was tested on my 2013 F70 and my 2022 115 SHO Yamaha and I "suspect" that is the way Yamaha makes all their more recent ignition switches, and it might work the same way for you? Easy enough to test for sure... And it could work for other makes / years of Outboards knowing how they all source many of the same parts from the same vendors. I do know that my past 2004 Honda simply would not even turn over if it was disconnected. Again, easy enough to test if you would like to try this process and if nothing else, to ensure your safety switch is indeed working as designed? I would just make sure; you have water hooked up and flowing through a set of muffs and the prop is clear before trying. Hope this helps extend the life of your Outboard, and do let us know your results!

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