I have a 2 stroke outboard, so I mix my oil and gas in a 5 gallon can and pour it into the boat.  Messy and a pain.  This may seem like a silly question, but can I just pull up to the pump, pump in 5 gallons, and then just pour in the required amount of oil?  Will the sloshing around as I drive adequately mix it?

I always put the oil in first, then add the gas. Been doing it that way for years with no problems. 

The way I do it is put in 3 gallons of gas, put in 8 oz of oil, put in 3 more gallons then 8 oz of oil and so on until it's full.  I'll jerk the boat a few times to be sure it's  mixed.

When I had an outboard like that I put the gas in and then the oil. It will mix with no problems while going down the road.

It is going to get mixed regardless how you do it if you do any traveling after you put it in.

 

Gas and oil both come from crude.  So they mix fairly easily.  It's not like trying to mix oil and water.  Also, at the typical ratio of oil to gas, there's not much oil in the mix to begin with.  So I can't imagine it's too critical that every drop be equally mixed.  

 

I'd just fill it with a little bit of gas, just enough so cover the bottom of the tank, then put in the oil, then fill the rest with gas.  The force of the gas coming from the pump will do a good job of mixing the two.  Combine that with a bit of driving around, and you'll be fine.

49 minutes ago, Bankc said:

I'd just fill it with a little bit of gas, just enough so cover the bottom of the tank, then put in the oil, then fill the rest with gas.  The force of the gas coming from the pump will do a good job of mixing the two.  Combine that with a bit of driving around, and you'll be fine.

This is exactly how I did the mix for my old 40HP Evinrude on the runabout...never had an issue.

Been running 2-cycle LawnBoy mowers since I was in grade school...and 2-cycle outboard in my boat for the past 20 years. 

 

I've done it both ways...oil first, then gas.  Gas first, then oil.  Works either way. Preferred method is to go oil first, then fill with gasoline

 

Side note:  I always, I mean ALWAYS use ethanol free fuel. This is CRITICAL in my opinion. I have never had a fuel related issue with any of my small engines or outboard motors.

28 minutes ago, DaubsNU1 said:

I always, I mean ALWAYS use ethanol free fuel.

Agreed.  I bought my old boat a few years ago, and it came with a working separate oil mixer, but everything I read said to cut it out of there, that the first time I realized it wasn't working was when the engine seized up.  So now I mix.

52 minutes ago, billmac said:

Agreed.  I bought my old boat a few years ago, and it came with a working separate oil mixer, but everything I read said to cut it out of there, that the first time I realized it wasn't working was when the engine seized up.  So now I mix.

 

Ouch! Bummer...

 

7 minutes ago, DaubsNU1 said:

Ouch! Bummer...

Well, it didn't happen.  I was just warned it would happen.