Best Oil for '75 Merc 650

[mercurymang]

I'm quite sure this has been discussed ad-nauseum some where on here but I couldn't find it so I'll ask the question. Walmart has the Quicksilver premium plus with the red label for $20/gal. They also have the QS synthetic in the blue label for $27/gal. I usually buy the 16oz synthetic for $4 as it mixes perfectly into my 6gallon tanks. Anyone ever run the red label stuff in their merc two-stroke? Just wondering if I could save some money or should I stick to the synthetic.

 

[matt167]

Re: Best Oil for '75 Merc 650

Plenty here recomend the Walmart Supertech TCW3 as if you look at the MSDS and oil breakdown sheets. It actually is a better oil than most TCW3.. Your '75 650 ran on dino oil long before synthetic TCW oil was even thought of.. If you give the engine the correct spec oil in the proper ratio, then it will run for a long time.. IIRC the Supertech is $12/gal

 

[mercurymang]

Re: Best Oil for '75 Merc 650

This stuff? Super Tech TC-W3 Outboard Motor Oil - Walmart.com

Nice, that'll save me quite a bit.

Thanks Matt.

 

[emckelvy]

Re: Best Oil for '75 Merc 650

Besides oil, the most important thing you can do for your 650 Triple is give it a new impeller once a year!

These old-style Triple blocks will crack at the top of #1 cylinder when they overheat, so the impeller is cheap insurance for your motor.

Another worthwhile improvement is to move the telltale to the top of the block, as was done with later models. This ensures the block is properly vented and completely full of water, preventing pockets of steam from forming. This cuts down on the block-cracking as well!

Check out this parts diagram of a 60hp Triple block, you'll see the telltale fitting (part # 30) at the top. A 90 deg 1/8"-NPT fitting placed in the top-of-the-block in the same general vicinity as that fitting would do the job nicely. Then you just plug off the old telltale hole.

Mercury Marine 60 HP (3 CYL.) CYLINDER BLOCK AND CRANKCASE ASSEMBLY Parts

IMHO, HTH.............ed

 

[mercurymang]

Re: Best Oil for '75 Merc 650

Besides oil, the most important thing you can do for your 650 Triple is give it a new impeller once a year!

These old-style Triple blocks will crack at the top of #1 cylinder when they overheat, so the impeller is cheap insurance for your motor.

Yep, got that done. I intend to keep up with that.

Another worthwhile improvement is to move the telltale to the top of the block, as was done with later models. This ensures the block is properly vented and completely full of water, preventing pockets of steam from forming. This cuts down on the block-cracking as well!

Check out this parts diagram of a 60hp Triple block, you'll see the telltale fitting (part # 30) at the top. A 90 deg 1/8"-NPT fitting placed in the top-of-the-block in the same general vicinity as that fitting would do the job nicely. Then you just plug off the old telltale hole.

Mercury Marine 60 HP (3 CYL.) CYLINDER BLOCK AND CRANKCASE ASSEMBLY Parts

IMHO, HTH.............ed

Interesting. I learned this from some guys over at JohnsOldMercurySite. I floated that idea here and didn't seem to get too much of a bite on it. I had intended to do it but frankly I'm very hesitant to drill a hole in a perfectly good motor. Maybe I need some more encouragment.