Mercruiser 4.3 Oil

[trailshredder]

The service manual for my 87 Mercruiser 4.3 says to use Straight 40 weight, 20W40 or 20W50 Detergent Oil. Since it was written 25 years ago and those aren't as common as some of the lighter weights, can I use something else? I did find a walmart brand but it didn't say if it was a detergent oil. Suggestions?

 

[Levinz11]

Re: Mercruiser 4.3 Oil

I love oil threads. Someone will post the (updated) Mercruiser reccomended oil info. I use Castrol 10w-40 in my heep.

 

[Don S]

Re: Mercruiser 4.3 Oil

Here is direct from Merc.
MerCruiser Fuel & Oil FAQs | Storage & Maintenance MerCruiser FAQs | Mercury Marine

If that's not what you want, have a look at the last threads in this forum.
Non-Repair I/O and Inboards - Page 66

 

[RogersJetboat454]

Re: Mercruiser 4.3 Oil

The service manual for my 87 Mercruiser 4.3 says to use Straight 40 weight, 20W40 or 20W50 Detergent Oil. Since it was written 25 years ago and those aren't as common as some of the lighter weights, can I use something else? I did find a walmart brand but it didn't say if it was a detergent oil. Suggestions?

I believe the going conclusion after hundreds of "what kind of oil to use" threads is this;
If you're not going to use what the MFG suggests, use what ever makes you happy. Everybody has their own opinion, what ever makes THEM happy, right?

As far as Wally World oil, If it was 20W-50, chances are pretty good it was a detergent oil. Haven't seen any split weight oils that were non-detergent. Usually just a single weight like 30 or 40, and the bottle is usually well marked "Non detergent", or "ND". Look at the back of the bottle for the gold seal, and it will tell you the service grade that the oil is rated for. Something like SG, SH, SJ, etc...

 

[trailshredder]

Re: Mercruiser 4.3 Oil

I should have known and searched first. I think every forum I am a member of that has an engine, oil is one of those subjects that gets a billion opinions. BTW .... Just bought some Quicksilver Synthetic Blend 25W40 from Wally World. Didn't think to check the marine section yesterday. Some pricey oil, but since it will only get it once a year, suppose its worth it.

 

[MarkSee]

Re: Mercruiser 4.3 Oil

.... Just bought some Quicksilver Synthetic Blend 25W40 from Wally World....

That's better than the 5 or so WW I shop here in SoCal that all seem to carry the Quicksilver HiPo gear oil and some 2 cycle marine oil but none that actually carry any Merc engine oil I can use in my boat.

Mark

 

[Silvertip]

Re: Mercruiser 4.3 Oil

I was at my local farm store today (Fleet Farm) and there is an ample supply of 15-40, 15-50, 10W-30, 10W-40 any of which can be used and probably far cheaper than buying oil at a marine dealer or marina.