What's the easiest/cleanest way to pre-mix two stroke gas with built in gas tank?

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z33tec

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I just picked up a Sea Nymph with a 70hp Johnson two stroke. The previous owner disabled the VRO, so that means I'll have to pre-mix the oil (debatable on whether that's better or not than the VRO it came with, but anywho.)

The question I'm having is, the boat has the gas tank "built in" under the floor, and there's just a gas filler cap behind the outboard. What's the cleanest/easiest way to premix the gas and oil and fill it up? Fill it with gas at pump then put the oil in a small gas can with a nozzle and do it that way? Also, would it mix with the gas properly just doing it that way and not really being shaken up at all?

And yes, I realize this is probably a stupid quesiton :lol: First two stroke I'm dealing with since an old chain saw I had.

Thanks for any assistance!
 
I used one of these. Just top off the tank, note how many gallons you put it in, measure the corresponding amount of oil, and dump it in. About as painless as it can be.

https://www.walmart.com/ip/Attwood-11873-1-Wide-Mouth-Marine-Fuel-Oil-Mixing-Bottle-1-Quart/38057090?wmlspartner=wlpa&selectedSellerId=5155&adid=22222222227026950857&wl0=&wl1=g&wl2=c&wl3=43324546712&wl4=aud-430887228898:pla-82772113472&wl5=9023412&wl6=&wl7=&wl8=&wl9=pla&wl10=125208114&wl11=online&wl12=38057090&veh=sem&gclid=CjwKCAjwxLH3BRApEiwAqX9arVeI_ltBCAHn-uLTOEN1fqZz080g1YZt--QoYTl1MilOkndQ8HZiyxoCJ2EQAvD_BwE
 
So you bought the boat. We are going to require pictures so we can celebrate with you! I like to fill the tank and put a shot of gas aside to mix the oil in and then dump the mix in the tank. This makes sure the oil doesn't just coat the filler neck but goes right into the tank. To clarify, I put x gallons in the tank, calculated x ounces and put that in a mixing container and ad the slosh of gas, swirl it around and dump it down the filler.

Sent from my CLT-L04 using Tapatalk

 
I think I'd reverse the order that Weldor suggested. Mix your oil into a gallon or two, outside the tank. Pour it in, then proceed to fill the tank. The action of filling will mix that oil-heavy "charge" into the added fuel quite well.
And, yes......pics are a must.

Roger
 
GTS225 said:
I think I'd reverse the order that Weldor suggested. Mix your oil into a gallon or two, outside the tank. Pour it in, then proceed to fill the tank. The action of filling will mix that oil-heavy "charge" into the added fuel quite well.
And, yes......pics are a must.

Roger
I've done that when I knew exactly how much fuel I was putting in

Sent from my CLT-L04 using Tapatalk

 
I always had 2 5 gallon cans I used to put the oil in, then fill with gas and top the tank off with those. if it was really low I'd put the oil directly in the tank for 5 or 10 gallons worth of fuel and then fill at the pump and watch the meter. sometimes a combo of both so I always kept it consistent. I haven't seen any recommendations I would argue with though. I was always afraid of getting the mix too lean or rich so I did it this way.
 
The above solutions seem overcomplicated to me, but to each their own.

Assuming a 10 gallon fill up, that's 25 ounces of oil at 50:1. The oil film left in the filler tube would be inconsequential, if not totally washed away from gas splashing around on the way to the lake. Just dump it in, no need to overthink it.
 
Thanks guys! I really appreciate all the helpful tips! I was surprised to see how many replies I got what I assumed to be a dumb question :lol:

I'm going to take the advice here and get a separate can to do the mixing. I saw those measuring bottles and had planned on picking one of those up too, they just didn't have any way of cleanly pouring it in to the filler cap I have on my boat so that's what had me questioning.

Thanks again and I will definitely be posting a separate thread with some pics as soon as I take some! So much to learn still! You guys are awesome.
 
MrGiggles said:
I used one of these. Just top off the tank, note how many gallons you put it in, measure the corresponding amount of oil, and dump it in. About as painless as it can be.

https://www.walmart.com/ip/Attwood-11873-1-Wide-Mouth-Marine-Fuel-Oil-Mixing-Bottle-1-Quart/38057090?wmlspartner=wlpa&selectedSellerId=5155&adid=22222222227026950857&wl0=&wl1=g&wl2=c&wl3=43324546712&wl4=aud-430887228898:pla-82772113472&wl5=9023412&wl6=&wl7=&wl8=&wl9=pla&wl10=125208114&wl11=online&wl12=38057090&veh=sem&gclid=CjwKCAjwxLH3BRApEiwAqX9arVeI_ltBCAHn-uLTOEN1fqZz080g1YZt--QoYTl1MilOkndQ8HZiyxoCJ2EQAvD_BwE

That's what I use on my non-injected boat. Perfect.
 

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