Mercury Thunderbolt 650 4 Lube Question

[ArmyVeteran_721]

I'm sure many have already asked this question, my apologies in advance if that's the case. I just need to know what weight of oil I need for my lower unit, and also any specific oil Type I need to add to the gas, Thank you guys very much!

 

[alldodge]

Howdy

Here is a link which list all of the greases and lubes used on your 650 4cylinder
http://www.mercruiserparts.com/Show_...ases+and+lubes

http://www.mercruiserparts.com/Show...desc=4+Stroke+outboard+oil+-+including+Verado

 

[flyingscott]

You need any tcw 3 oil for the fuel mix and 80w 90 marine lube for the lower unit.

 

[alldodge]

Not an outboard guy flyingscott but I'm pretty sure this is a 4 stroke, isn't it?

 

[racerone]

I think the OP has a 4 cylinder 2 stroke 1971 or older !

 

[flyingscott]

Mercury used the thunderbolt designation in the 60s and 70s. They also added a 0 to the HP rating at the same time a 650 would be a 65 Hp . That is why I think it's a 2 strk to early to be a 4 strk.

 

[alldodge]

I'll go back and sit on the couch

 

[GA_Boater]

Saving a spot on the couch, AD. LOL

Merc 650 is a 2 stroke for sure. Like my Merc 500, knock off a 0 for the HP. *

For the 2 stroke oil, WallyWorld has you covered. I like the Synthetic Blends by Pennzoil - Just my personal preference. WW carries the Mercury.Quicksilver lower unit lube - One for higher horsepower and one for lesser HP - Look at the label for the right one, I think 90 HP up is one of them.

*flyingscott had this covered. :doh:

 

[flyingscott]

One thing I forgot you need to mix the fuel oil at a 50-1 mix.

 

[GA_Boater]

Forgot to :welcome: you to iboats, Vet.

If this is a new to you motor and history is missing, it's a good idea to replace the water pump impeller. Mainly because it's one of the most critical things and one of the most neglected. Might be a good idea to put a new one in anyway, just for peace of mind.

While you're at it, change the lower unit lube. From your question, it looks like that's the direction you're going. Just making sure.