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Summary tests synthetic engine oil in an outboard motor and sees a 3.5 – 14% improvement in fuel economy using Royal Purple.

Note: Improvements in performance depend on the vehicle, it’s condition and how it’s used. This video is not intended to imply that all users will experience the same performance gain by upgrading to Royal Purple.


[Disclaimer: The opinions expressed in the video you are about to see are solely those of and it's Test Captain.]

Captain Steve Larivee: Hi. Captain Steve of and today we're going to do a test with Royal Purple. We've tested it on inboards before. Today, we're going to test it on an outboard. We found a yard boat, with a Mercury 40 EFI 4-stroke and it's got 400 hours on it.

We're going to run it up, find out what the parameters are with its existing oil, then change it and we're going to run it up again. We've got the hose connected to it, so we're not going to have anything on the water, we're not going to have waves or anything like that affecting our parameters, it's out off the water.

We're hooking up a laptop with diagnostic programming into it that will give us 17 different parameters for reading out what the engine's putting out. As a backup, we've also hooked up our own fuel flow meter. So this will tell us exactly what is going on with this outboard.

Narrator: Now, we've collected the numbers for the brand name synthetic oil, so let's switch over to Royal Purple and rerun the numbers.

Captain Steve: The first thing I'm going to do is go ahead and drain the oil. Now I'll take the oil filter off and of course, I don't dress like this every time I do an oil change but for you folks, I'll stay pretty.

Now, we'll add the Royal Purple in. Okay. So now we've got the Royal Purple in. Let's fire it up and get some new test numbers.

Narrator: In the low RPM range, we found no change in economy between Royal Purple and the brand "X" synthetic oil. In the mid-RPM range, where most of use our boats, we found a significant difference, ranging from 20% at 2500 RPM to 12.5% at 4000 RPM giving us an average of 14.6 improvement fuel economy.

At the high RPM range, we saw changes ranging from 6% at 4500 RPM to 2% at 6000 RPM, but we also found a 9.4% decrease in economy at 5500 RPM with Royal Purple.

At first we thought that this was an anomaly, but we ran the number three times and it came out the same every time. So, if you insist on using the brand "X" synthetic oil, we suggest that you only run your engine at 5500 RPM.

Overall, our tests show the engine was 3.5% more efficient when running with Royal Purple. Now that doesn't seem like much, but in the critical midrange between 2500 and 4000 RPM, where most people run their boat, giving us an average of 14.6 improvement of fuel economy.

At the end of the day, with all the variables taken out, it appears that it works as advertised. From, I'm Captain Steve. We'll see you on the water.