15w-40 in my boat, is diesel oil OK?

[BrocLuno]

Unless that water is frozen all around the hull, the bilge temps will always be high enough for 15W to work. Yeah, the motor might turn over a slight bit easier with 5W when the ice flows are forming... But 15W is fine most times for any boat. The water around you helps moderate the low temps

 

[rokwldr]

I've been using NAPA 15-40 diesel in my Yamaha 115 4-stroke for 4 years and never a problem. If you had a catalitic converter maybe it would screw up. It's fine, use it.

 

[rokwldr]

Been using NAPA 15-40 Universal Fleet for years in my Yamaha F115. Never a problem. Yamaha oil has 1100ppm zink as does all deisel oil. The Yamaha F115 is a flat tappet engine needing this extra protection. Read the MSDS.

 

[terminaldegree]

I ran Delo 400LE 15w-40 in my Nautique this year and everything seemed fine. I picked it over the ever-popular Rotella because some of the VOA's I saw indicated it may have slightly more ZDDP. There are so many other maintenance items on a boat that tend to get ignored that I would never spend more on synthetics. For that matter, everything gets changed pretty frequently anyway.

 

[CT8]

Originally Posted By: yvon_la
cj-4 oil are designed for engine with total sulfur content of max .5 % so no you likely cant use that oil if it is a sn/cj-4 oil

you ll damage your engine
How will the oil damage the engine?

 

[CT8]

Originally Posted By: terminaldegree
I ran Delo 400LE 15w-40 in my Nautique this year and everything seemed fine. I picked it over the ever-popular Rotella because some of the VOA's I saw indicated it may have slightly more ZDDP. There are so many other maintenance items on a boat that tend to get ignored that I would never spend more on synthetics. For that matter, everything gets changed pretty frequently anyway.
A happy boat is an over maintained boat ! Time on the water is too valuable to chance a break down from neglect.

 

[BrocLuno]

That's SM right there. Run it with confidence