I only have 5 hours on ur oil in my 4 stroke used Yamaha so have not put it to the test ! However I have used it in my Indian motorcycle some years back and would say that it never failed. I have friends who swear by it. I believe it to be superior oil.

Quality product, have used it for years and no issues.

I have trusted this oil in my Volvo Penta 5.0 V8 for many years, and in my Mercruiser 5.7 V8 before that. These engines always started and ran perfectly. Great protection.

I ran it in my 4.3 mercrusier and it worked great, I am going to run it next year also

Good for smaller trolling motors without oil filters

I am using this on a 2017 Mercury 115 four stroke. I like the idea of having extra protection from a full synthetic, especially in tough marine conditions.

Used in a high revving supercharged Yamaha jet boat that is mostly used in the ocean and I Change oil every 50 hours and engine does not consume a drop of it.

I run this oil exclusively in my 425 HP Yamaha SX-195 Race Boat. It delivers the performance that I need in a high boost application!!

I owned a taxi and shuttle service and did all my own maintenance. I used Amsoil in everything. Never lost a transmission or engine and retired vans at 750,000 miles.

Been running this for a long time

This is my first boat. It has a Yamaha 175hp SHO 4-Stroke. I have Amsoil in everything I own. After the breakin hours passed. I replaced everything with Amsoil. Motor,lower unit and bearing grease. It's the only oil for me. Always a Great choice.

I use this great lube oil for my 1990 Cruisers Esprit with twin Crusader 350's. I am never disappointed with this synthetic, even though they were designed for straight SAE 40. They run smooth and oil pressures are spot on.

Fantastic no issues with this product will buy again and recommend it Thanks

Great product, love it

Use Amzoil in all my cars and motorcycles, jetski's etc. Never had an oil related failure. Will continue to trust Amzoil.