The oil in my 98 Johnson 150 lower unit is really nasty looking. I want to replace with Royal Purple synthetic but I would like to flush the gear case before I do. Is there a safe and effective way of doing this or do I just need to drain and refill. Thanks
To be honest, you don't really accomplish anything by "flushing" the case. If you have metal fragments floating around inside, you need to find out what caused this by looking inside the case. If you have old looking oil, let it drain overnight and refill. If it's watered down, then you need a pressure and vacuum test to see if a leak can be found. The Royal Purple is good stuff. Good choice !!
Cool, thanks for the info. I did have a small amount of water so I will test for leaks. Yep, I'm running the Royal stuff based on your reccomendations. I would love to free up the case and get a few more rpmI run synthetic in everything else I have so why not my lower unit.
Good point !! I run R.P. oil in my old chevy 327, and picked up @ 4 M.P.G.
<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by gearcaseman »</td></tr><tr><td class="quote">Good point !! I run R.P. oil in my old chevy 327, and picked up @ 4 M.P.G.
Looks like I need to do that to my old 94 chebby wid 190 hp 350...WTF?????
Hey, you might be pleasantly surprised, who knows???
Wow. 4 MPG. It's definitely worth a try..
Rick
what is this royal purple you talking about?
do they make a lower unit oil or do you just put regular 75w-90 gear oil in?
<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by sandbarDan »</td></tr><tr><td class="quote">what is this royal purple you talking about?
do they make a lower unit oil or do you just put regular 75w-90 gear oil in?</td></tr></table>
Pretty much, cures everything from Hemmoriods to the common cold.
awsome I'll put some in instead of the xd50 too!!!
I actually haven't tried it on the hemmoroids yet, but all my customers that switched to it picked up 300-400 R.P.M.'s on the top end. The factory engineers finally realized that the lighter weight oil made a huge difference in the efficiency of the case and "Presto", they began to make their on brand of synthetics just for the lower units. Imagine That!! Anyway, it works great and it's a very good product. You can find it at most of the O'reilly stores. Try the 75-90 gearoil.
the 300-400 rpms seems a little high unless they were using vaseline before.
but what the hell I'll give it a try, my motor should do about 6200 then. wonder how serious Johnson was about that 5500rpm max?
<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by sandbarDan »</td></tr><tr><td class="quote">the 300-400 rpms seems a little high unless they were using vaseline before.
but what the hell I'll give it a try, my motor should do about 6200 then. wonder how serious Johnson was about that 5500rpm max?</td></tr></table>
When your internals start to become externals., give me a holler.Gearcase
So....Just to verify, I can safely run the RP 75w-90 in my 98 200 venom?
<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by sandbarDan »</td></tr><tr><td class="quote">the 300-400 rpms seems a little high unless they were using vaseline before.
but what the hell I'll give it a try, my motor should do about 6200 then. wonder how serious Johnson was about that 5500rpm max?</td></tr></table> They were pretty serious about it actually. The R.P. is a way to make your rig a little more efficient, not a guarantee that you'll see those kind of R.P.M. increases.
So if a motor was turning max RPMS with Evinrude gear oil then switched to the Royal Purple gear oil that's suggested he likely might see a RPM increase and then may be able run a pitch more on the prop and gain speed and performance and bring max rpms back to the factory recommended limit.Is my thinking correct??
<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by Ranger692 »</td></tr><tr><td class="quote">So if a motor was turning max RPMS with Evinrude gear oil then switched to the Royal Purple gear oil that's suggested he likely might see a RPM increase and then may be able run a pitch more on the prop and gain speed and performance and bring max rpms back to the factory recommended limit.Is my thinking correct??</td></tr></table>
Yep.
Thanks for the info.Used penzoil gear lube in the past but this fall put the Evinrude stuff that a local marina suggested when I winterized.Will run that for a while this spring to see if there is any rpm difference between the penzoil and the Evinrude oil.Then might have to try the Royal purple stuff and see what happens.With all the trouble and money we spend to get most out of our motors this almost sounds too easy to be true but sometimes the little things are what makes the most difference.Thanks for all the knowledge and experience you guys share on this board...ED
1994 Evinrude 175 intruder self mixed
1998 Ranger 692
You're on the right track, but again, not all boat/motor combinations will see the noticable increase in R.P.M.'s. There are many variables to be considered here. For example, what type of oil was used before, is the craft set up for maximum performance, what type of boat is involved. The type of rig that will see this kind of performance will be the ultimate set up by the most particular boat owner that has more than average knowledge of performance modifications. Boat hull design and weight have much to do with the overall increases one can expect from simple alterations.
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