The Hull Truth - Boating and Fishing Forum - View Profile: mwn


mwn mwn is offline

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  • Last Activity: 12-27-2019 07:15 PM
  • Join Date: 02-04-2013
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Showing Visitor Messages 1 to 2 of 2
  1. 10-23-2015 05:10 PM

    Yamaha now says to only fill to the half way level [why no half way mark on the dipstick to take the guess work out?]. They say this to allow for the engine to "make" oil during use. That is the engine crank case takes on GASOLINE during operation. If the engine was filled to the full mark when the oil was changed the "making" of oil would result in too much "oil" in the engine.

    Yamaha does not know which specific engines will "make" oil, they do know which models are more prone to do it. So as not to alarm owners they now say only go 1/2 way and not to worry if the level rises but stays below full.

    It should be pointed out that four strokes are not designed to run with gasoline mixed in with the oil unlike two strokes.

    The bottom line is the "half way fill" is an attempt to mask the problem of gasoline getting to the pan, unfortunately it does not stop the dilution of the oil.
  2. 10-23-2015 05:09 PM
    Old guy here, for as long as I have been around it has been safe to run an engine with the oil level from "add" to "full".

    For just as long it has been practice to fill the pan to the full mark when changing oil, ie when the oil is cold. There is no need to leave room in the pan for the expansion of the cold oil as some Yamaha dealers are now saying.

    The manufacturer knows we add cold oil when changing oil, they mark the dipstick "full" at the point the pan should be filled to with cold oil. This prevents the crank form foaming the oil when the engine is hot and allows for some oil to leak/burn off before any needs to be added. Ideally no oil is needed between changes.

    to be continued

Likes Given

  1. mwn liked post by HTJ On thread : Planning on single engine
  2. mwn liked post by ondarvr1 On thread : Question about e10 gas and old two stroke engine...

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