mercruiser 4.3 I/O oil type and weight?

Fishermark

Vice Admiral
Joined
Oct 19, 2003
Messages
5,617
Re: mercruiser 4.3 I/O oil type and weight?

From Mercruiser:

Engine Oil

For optimum engine performance and maximum protection, use the following oil:
Application Recommended Oil
All MerCruiser engines Mercury MerCruiser Full-Synthetic Engine Oil, 20W-40, NMMC FC-W rated

IMPORTANT: Lubrication requirements for catalyzed engines differ from the requirements for non-catalyzed engines. Some marine-grade lubricants contain high levels of phosphorus, which can damage the catalyst system on MerCruiser engines. Although these high-phosphorus lubricants may allow acceptable engine performance, exposure over time will damage the catalyst. Catalysts damaged by lubricants containing high levels of phosphorus may not be covered by the MerCruiser Limited Warranty.

If Mercury MerCruiser Full-Synthetic, 20W-40 oils is unavailable, use the following lubricants, listed in order of recommendation. If you are servicing a catalyst engine, use these for short periods of time only.

Mercury/Quicksilver 25W-40 Synthetic Blend, NMMA FC-W-rated 4-cycle MerCruiser oil
Mercury/Quicksilver 25W-40, NMMA FC-W-rated 4-cycle MerCruiser oil
Other recognized brands of NMMA FC-W-rated 4-cycle oils
A good-grade, straight-weight detergent automotive oil according to the last row of the operating chart below.

NOTE: We do not recommend non-detergent oils, multi-viscosity oils (other than as specified), non-FC-W-rated synthetic oils, low-quality oils, or oils that contain solid additives.

This crankcase oil recommendation supersedes all previously printed crankcase oil recommendations for MerCruiser gasoline engines. The reason for this change is to include the newer engine oils that are now available in the recommendation.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
13,150
Re: mercruiser 4.3 I/O oil type and weight?

4.3 takes about 3.5 qts plus about .5 qt for the filter.
 

Fishermark

Vice Admiral
Joined
Oct 19, 2003
Messages
5,617
Re: mercruiser 4.3 I/O oil type and weight?

Most important note about capacity is to check the level on the dipstick with the boat in the water - not on a trailer.
 
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