Custom Baits - Forum
General => General Discussion => Topic started by: Justin9j on 02/14/12 20:42 UTC
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I value everyones opinion on here. So i hope it is ok if i ask a boat question. I have only had a boat for 9 months now and have a question about lower unit oil.
Synthetic oil or not. Motor is a 90 70hp johnson. I know syn is not what it calls for but I have heard syn will get you more rpms.
And what brand do Most of you guys run.
Thanks Justin
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Typically Synthetic oils are more stable, more "Slick", and offer better lubrication performance. I am not an expert in lower unit lubricants. I would ask a qualified / certified outboard mechanic about your particular engine. I do know the new 100% synthetic oils that are approved for my engine type provide smoother performance in my aged 2 stroke Yamaha. I also never run anything except 100% gasoline in the engine. Never any alcohol blends; ever. This is after an engine rebuild quite a few years ago when the master mechanic said to me "If you value this engine, run only 100% gasoline and top grade oils". Based on what I paid him for his expertise on the rebuild, I have taken his advice.
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I would stick with the manufacturer recommendations or for an older motor an experienced technician. I have an older 85 HP Johnson and I went with the standard stuff. More RPM's isn't always good. For good boat performance the prop, motor, and lower unit must by in sync or you could have problems.
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Agreed. An engine is designed to run within certain parameters. Over rpm's or over propping are really tough on an engine, especially an older one. I have no idea how long it has been since I ran my Yamaha at or above 4,500 rpm (engine orange line of 5,300 ). Usually run 3,500 - 3,750. Note in my earlier post I said smoother, not faster. The engine has the Yamaha factory prop of the correct pitch for my "full load" boat weight. Faster can become expensive very quickly.
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I was not really looking for more rpms. Just thought if it helped the motor work less it would be a good thing. I tournament fish some but with a 70 hp I'm not out running anything but a paddle boat. So I don't get in to big of a hurry anyway. We own a auto repair shop here. But boats are a different animal. I'm still learning. I just don't want to learn the hard way.
Thanks guys.
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The main thing is 100% gas and the best 2 stroke oil that is approved for your engine at the correct add rates. A good quality gas treatment / stabilizer is a good idea as well. Sta-bil ( blue ) and sea foam are the two most mentioned in the forums. I use Sta-bil blue; with yamaha ring free every 4 to 5 tanks.
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x2 2 on everything above. Stay away from ethenaol.
Just as an FYI - the one time I got fancy with a motor and tried to get a little more out of it I blew it up! I'm sure it was more about how I was using it, but who knows for sure.
Jason
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thanks everyone. for the help.