Question for the Experts

This topic has 4 replies, 5 voices, and was last updated 17 years, 2 months ago by basschaser.

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March 20, 2009 at 12:46 am #331259

tschooler1956
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Concerning Lower Unit Gear Lube, for a 08 Hammer 250 Series 2. Need to know the best lower unit gear lube. Dont have a problem sticking with the manufactures lube but some of the tests I have been reading show Mercurys HPF and Evinurudes HPF XP better for water intrusion and friction tests at WOT. Can or should you even attempt to run other brands? Just want the best. Thanks

March 20, 2009 at 2:59 am #331280

bworner
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Tschooler if she is under warranty I believe its in your best interest to use what yamaha recommends…now if they say “any approved marine lower unit fluid”, then by all means get the best stuff, and in my opinion 1st would be the BRP XR synthetic that the E-TEC runs, in most of our motors its clean for the 3 years+, 2nd Mecury High Performance lube…..check your book if its vague ask a trusted service manager or tech, just dont tell them your name or serial #……Thats my advice, we use the BRP stuff in our Mercs and Etecs, heck we use it in the Tohatsus, and customers Hondas, Suzukis, and Yammies……Brannon Your Signature …

March 20, 2009 at 5:38 am #331300

oldtimer57
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Im not a particular fan of synthetic in the lower unit. It wont mix with water at all. If you get a little water intrusion, the oil will not emulsify with the water, so any sort of quick check wont show the problem. But those water droplets can collect at a bad place and invite some rust. My favorite for years has been a “mixture”. Merc non-synthetic lower unit lube, plus a bottle of the teflon friction reducer from Bobs Machine down in FLA. This stuff is yellowish and is slick as owl sh** mixed with motor oil with a overcoat layer of grease on it. I have tortured a lower unit (the small XR6 gearcase) spinning a 28″ chopper at 6K or so for 10 years now and all I do is replace the seals every year or two (I have removed the inner exhaust liner among other things and the shift-shaft seal gets a little hard after 2-3 years so I replace before it starts to leak in a place that is impossible to see, but which will let the oil out and the water in while you are fishing. I like the non-syn oil as I can pull the drain plug with a small clear glass cup under it, catch a teaspoonful of oil and determine if it has emulsified by mixing with water that ought not be present. I could never “read” the syn oil like that, unfortunately, although it is a better material overall.2008 Pantera Classic2014 Mercury Pro XS 200

March 20, 2009 at 3:37 pm #331319

tswanson
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I use synthetic in everything from my 15 Evenrude to my 330hp/Alpha One – For many years. The Alpha One gets so hot water boils off the top of it (I dont have a spray bar dumping water on top of the unit to cool it). Oil and water does not mix. Water will sink to the bottom of the gearcase. The problem is the layer of water. Water causes rust and is poor lubrication. The old non-synthetic heavy duty gearcase lube did not encapsulate water causing a layer of water in the bottom of the gear case. Synthetics have emulsifier stablizers. The oil encapsulated water. Water in the lower unit will appear as tiny bubbles dispersed throughout the gearcase. When draing the lower unit let it run it thru your hand. You can feel that it the gearcase lube is still very slippery even with the water trapped in it. One summer the Alpha One took on water fast. I wanted to wait till winter to reseal it. I changed the synthetic oil mid-summer that year. When I resealed the gearcase I inspected the gears, bearings, shifter and clutch dog. They were fine even with water in the lower unit for an entire season.

March 21, 2009 at 3:38 am #331339

basschaser
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Get the Yamaha lower unit grease and be done with it. These motor manufactures arent making their money on the oil but instead the engine sales. They have the oils/lubes because they designed their motors to use them. That is exactly what you need to be running. Judd Lasiter
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