Synthetic 2-Stroke oil

[larrymul]

I"m the new owner of a bass boat with a Mercury 200 hp outboard, the boat is an '88, I assume the motor is '88 or '89. I've been all over inside and outside and cannot find any serial number in any places I see mentioned in various forums. Inside the cowling it stays Rev. 3-14-89 under a part number. I haven't ordered a manual for this motor yet.

I'm wanting to top off the fuel tank for winter storage, the previous owner has removed the oil injection system, but didn't tell me what oil he was using for his mix, he's in another state, I can't get hold of him. It's cheap insurance, so I plan to use good oil (Quicksilver?), just wondering if I can use synthetic, and whether it makes any difference if the previous owner was using fossil oil? Thanks, Larry

 

[Chris1956]

You must use oil with the TCW-III rating. Since these rate oils mix without an issue, use any brand you like, synthetic, blend or Dino versions. Obviously mix it 50::1.

You may use a fuel stabilizer if you like. You can fog the engine if you like. Some recommend, some don't. I definitely recommend changing the gear oil, greasing the fittings, and removing the prop, to allow greasing of the prop shaft.

 

[wired247]

If it had used full synthetic I wouldnt top it off and let it sit with dyno oil mix or vise versa. Depending on the brand they are not 100% compatible and you could get some sludge formation in the tank TCW 3 or not. Full the tank with gas and tie a quart of oil to the filler neck. Dump the oil in in the spring and burn it up as fast as you can run through it. You were going to do that anyway.

After that pick a brand of oil and stick with it. ( cough...Penzoil Marine synthetic blend premium )

 

[larrymul]

Thanks Chris and Wired (nice boat Wired...lotta motor there...), I've read some synthetics are compatible, the idea of filling the tank and using the oil necklace appeal to me. I appreciate the responses. Still trying to determine the motor year, but that's another subject.

 

[Chris1956]

I think Mercs of the late 80s had the clam shell style cowling. If you look on the crowleymarine website, you may be able to match up the cowling, and determine a range of ages.

 

[Texasmark]

If it had used full synthetic I wouldnt top it off and let it sit with dyno oil mix or vise versa. Depending on the brand they are not 100% compatible and you could get some sludge formation in the tank TCW 3 or not. Full the tank with gas and tie a quart of oil to the filler neck. Dump the oil in in the spring and burn it up as fast as you can run through it. You were going to do that anyway.

After that pick a brand of oil and stick with it. ( cough...Penzoil Marine synthetic blend premium )

I used that oil and really liked it, plus sitting side by side to Merc OEM it was half price. Very little smoke and with Sea Foam, my piston crowns were spotless. Since it is a blend, I see no reason why it shouldn't mix with dino oil, it's already mixed. On full Syn and I don't see any for sale around here, I never had a syn oil (non TC-W3) that said don't mix with dino oils. Course there's nothing magic about the marine oil other than additives as I see it so I don't know why it wouldn't mix. Both are oil and even if they didn't mix they both lube. While I'm yacking, I read on grease applications where they say don't mix types like Lithium with Moly for instance. Well both are grease and even though they might look like icing for a cake you are stirring in a bowl, they are both lubes and lube is what you are after. Course if you must have the retention properties of Moly then I could see that the Lithium could undermine that in areas where it alone was present.

Mark

 

[Dukedog]

Look at tha base of number 2 cylinder (top cyl on port side) on tha block half (cyl or back half) where tha block halves split. Kinda right behind tha bend in tha upper part of tha timing arm. There will be a build date (m/d/yr) stamped in 1/8" numbers. For serial number look on top of block behind flywheel for welsh plug. Looks like a freeze plug. It may or may not be there. Most did in those years but some will just have "200" stamped on 'em.......

 

[wired247]

I used that oil and really liked it, plus sitting side by side to Merc OEM it was half price. Very little smoke and with Sea Foam, my piston crowns were spotless. Since it is a blend, I see no reason why it shouldn't mix with dino oil, it's already mixed. On full Syn and I don't see any for sale around here, I never had a syn oil (non TC-W3) that said don't mix with dino oils. Course there's nothing magic about the marine oil other than additives as I see it so I don't know why it wouldn't mix. Both are oil and even if they didn't mix they both lube. While I'm yacking, I read on grease applications where they say don't mix types like Lithium with Moly for instance. Well both are grease and even though they might look like icing for a cake you are stirring in a bowl, they are both lubes and lube is what you are after. Course if you must have the retention properties of Moly then I could see that the Lithium could undermine that in areas where it alone was present.

Mark

I agree that oil is oil to an extent but Ive seen too many times over the years in non marine gearboxes and etc that full synthetic and dyno oil were mixed and it turned into jello. Too many times to be comfortable doing in something that mattered to me personally even if it is watered down with gas. May or may not be an issue but for something that is going to be set up for several months it seems like poor economy to take the chance. I like the mix it and go approach better.

 

[MH Hawker]

or the run it dry and start over.