Kicker oil question

[codybuehler]

I just bought a brand new Tohatsu 8hp 4 stroke motor.  It comes with no oil, so I am trying to figure out which oil to use in it.  I was going to get Royal Purple Synthetic 10w40, but I am shying away a bit.  The owner's manual for the motor says not to use synthetic.  There exact words are, "use of synthetic oil is not recommended in 4-stroke outboard engines. Outboards use raw water cooling systems and using synthetic oil may prevent the engine from reaching sufficient operating temperature."  Is there any truth in this?  I know synthetics are more efficient, but that efficient?  I have no issues with using either marine grade conventional or synthetic.  I just thought I would put this out there for some input from people who are more knowledgeable than I. 

 

Thanks!!

 

[Iceman]

CB:

There should be an alphanumeric designation for the grade of oil recommended for this engine, once you know this, you can select the correct oil.

John

Copied from the Tohatsu web site.

For your 4-stroke outboard, you should use Genuine Tohatsu FC-W 4-Cycle Oil. Tohatsu FC-W 4-Cycle Oil is NMMA Certified and has been specially formulated to handle the higher RPM's that outboards are subjected to, as well as special rust inhibitors to combat the harsh operating conditions of the marine environment. Genuine Tohatsu Oil reduces friction & wear and ensures the internal components are properly lubricated for optimum performance. If Tohatsu 4-Cycle Oil is not available we recommend using an NMMA Certified FC-W 4-cycle oil formulated for use in outboard engines. Look for oils bearing the FC-W trademark.

Your Tohatsu 4-stroke outboard is equipped with an Engine Oil Warning Lamp (except for 2hp, 2.5hp & 3.5hp). When the warning lamp is off, it indicates that sufficient oil pressure is present. If the warning lamp is on (red light is on) or blinking on/off, immediately shut down your outboard and check the oil level. Replenish as needed. If the oil level is at the appropriate level and the light continues to stay on or blink, consult your local dealer for assistance (do not use your outboard until a dealer has corrected the problem).

You may notice the engine oil warning lamp come on when you first start your outboard. This is normal and should go off after a few seconds. On cold starts, the lamp may stay on longer due to the oil being thicker. If so, stop the engine and restart and the lamp should go off quickly. If the warning lamp does not go out after 4-8 seconds, stop the engine and consult your local dealer.

Edited February 10, 2015 by Iceman

[Frogger]

Im not sure about the cooling aspect, but unless technology has dramatically changed you shouldn't be using a synthetic in a breakin period for a new motor or using it in a newer (low hr) motor.  Something about not getting the rings to sit like their supposed to.  There may be an engine techee that can chime in.  Just my humble knowledge.

[codybuehler]

Thanks for the info this far. I read somewhere about the break in and using conventional oil. As long as it has the fc-w on it, and isn't from the bargain bin, should be good.

Sent from my SM-G900V using Lake Ontario United mobile app

[Knotlost]

These are most all myths, they are from the days when synthetics were new. Call the tec support at amsoil and you will talk to an expert that can really help you. There are some places where there is a degree of difference but most of the time its simple ignorance, as a synthetic is not what most people think it is.