Oil for small 2010 Yamaha 4-stroke 4HP outboard?

Joined
May 30, 2008
Messages
2,376
Location
New York
I've read some threads debating what oil is suitable for larger 4-stroke outboards, but didn't see much for smaller engines. I recently purchased a like-new 2010 Yamaha 4HP. Peering at the oil it must have been changed before storage as it is perfectly clean. In fact, everything under the cover looks as clean as a new outboard. In any case, the manual specifies the following:

Recommended engine oil group 1*:
SAE 10W-30/10W-40/5W-30
API SE/SF/SG/SH/SJ/SL

Recommended engine oil group 2*:
SAE 15W-40/20W-40/20W-50
API SH/SJ/SL

It says to go for group 1 first, but if you can't obtain go for group 2. This chart seems to imply almost any automotive oil would satisfy group 1. For general protection reasons I'd like to use a full synthetic oil. But, I'd rather not pay boutique oil prices at the marine store for something labeled "marine" that might not be as good as standard automotive stuff. This thing will power a small dinghy and mostly see short runs of 15 minutes or less during the summer, so ease of pull starting is a factor more than hot running at WOT. Thoughts?
 
PM Pablo, he is an Amsoil Dealer, and he will point you in the right direction on what oil to use. I am guessing the recommendation will not be Pennzoil or Mobil 1

Of course, I could be wrong.
 
Why not NAPA full synthetic. It's reasonable priced. I doubt your engine will be tough on oil.

Although given the quantity of oil involved for a 4 HP outboard (I assume) you could use Yamaha brand and not break the bank.

Make sure it's gas rated oil however. Some of the heavy duty diesel rated oils are not gas rated.
 
I'm sure there's nothing wrong with Yamalube 10W-30, and it only needs 0.6 liters so cost is not a huge consideration, but I just like the potential extra protection going synthetic.
 
Most people in pleasure boating change the oil at 50 hours or once a season and mostly go less than 50 hours a season.

And with boating it's doubtful there will be very many winter starts when the temp is below zero. An area where full synthetic oil excels.

I am a big fan of synthetic oil and have been using synthetic since I got my new Jeep in 1976.

But not really needed in your case.
 
Most people in pleasure boating change the oil at 50 hours or once a season and mostly go less than 50 hours a season.

And with boating it's doubtful there will be very many winter starts when the temp is below zero. An area where full synthetic oil excels.

I am a big fan of synthetic oil and have been using synthetic since I got my new Jeep in 1976.

But not really needed in your case.
I hear ya, but the same arguments for non-synthetics could be made for most cars and trucks most of us drive. We could run the engines on dino oil for the life of the car, like we used to back in the day, but many of us still like to know we have that extra protection if the engine overheats, or the fuel gets diluted, or we make an unusual number of cold winter starts, or we have to run way over the recommended mileage for a change. Not critical, but I like the fact synthetics provide superior protection.
 
Back
Top