1990 Conbrio Oil? [Archive]

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StefK

07-22-2017, 10:19 PM

My first stern drive, beautiful boat with 650hrs with a PCM 351 Windsor. Looking to do an oil change after my next outing on the water. Any suggestions on what to run for engine oil? I'm located in AB Canada. Thanks!

crystal waters

07-23-2017, 09:59 AM

michael hunter

07-23-2017, 01:27 PM

For the past 30 years I have been running Mobil 1 15w50 in all my boats . 15 w 50 is the only weight recommended by Mobil for both roller and flat lifter engines.

StefK

07-23-2017, 09:37 PM

Thanks for the info gents. Michael, is the Mobil 1 15w50 you run in your boats a full synthetic or conventional? I tried to google Mobil 1 15w50 and could only find a full synthetic. If that's the case, I'm a bit leary as the original owner only ran conventional oil. With 650 hrs on the engine, I'm a bit reluctant to swap to a full syntheic at this point..?

StefK

07-23-2017, 09:45 PM

Manual says 30 weight oil for your average outside temp range.
See photo below taken from manual.
I have 89 conbrio with 351w and run 30 weight semi synthetic.
Enjoy you new purchase.
Great boat!

1824318243

So....are you running straight 30 weight or a 5w30/10w30 synthetic blend?? sorry for the dumb questions...

zroe

07-24-2017, 06:28 AM

I'm not sure if your motor is still a flat tappet or not but it wouldn't hurt to add some ZDDP or zinc additive just to be safe. Over the past decade or so they have removed a lot of the zinc and other engine protecting additives because they have a tendency to clog catalytic converters . Since you don't have to worry about cats in an older boat I would suggest an additive like STP's ZDDP as cheap insurance. I personally run Lucas 15w-40 Hot Rod blend with zinc.
Happy Boating!

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jbousman88

07-24-2017, 09:33 AM

I used Valvoline VR1 that has a zinc additive as well. I agree with the zinc comments above. Seems Mobile 1, Royal purple, Rotella, and VR1 all have pretty high Zinc

Zkdk3000

07-25-2017, 05:08 AM

Vr1 for me. But Michael Hunter is guru so either or. This is age old debate.

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