Suggestions on how to fill my onboard gas tank?

Chris1956

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Mar 25, 2004
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Gee, I cannot read all the posts. Likely some have been duplicated. It is real simple. Mix the fuel every 6 or 12 gallons. So get some pint or quart containers. Dump in a pint of oil, fill with 6 gal of gasoline, repeat with gasoline, and oil. when you think you are close to full, do 8 oz oil and 3 gal gas. If you mess up. modern motors run just fine on 24::1 ratios so you have a bit more smoke than usual.
 

BWR1953

Admiral
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Jan 23, 2009
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...My beat up old body wouldn't do well with hefting a bunch for fuel cans in and out of my truck, then up onto the stern of the boat. I do have a small fuel transfer pump, but the hose isn't long enough to reach the boat fill nozzle...
Hi guys. I guess I was too subtle about my concern. The italics above are the real issue. I'm talking about not being able to physically lift or lug fuel cans around, whether 5 gallons or 6 or 10 or 12; dolly or not. And I don't use a marina, so it'll be a gas station.

I already know how to correctly measure and mix the correct fuel/oil ratio. :sneaky:

It's been 30 years since I've owned a boat with an onboard fuel tank which had a 2-stroke engine and I just can't remember exactly what I did back then. 🧓

Since that time I've owned boats with built in tanks but 4 stroke engines or other boats with portable tanks and 2-stroke engines. And that's why I started the thread.

I think what I did before was to pour in X amount of oil to mix with 5 gallons of gas, then pump the gas in and repeat. I never actually filled the 18 gallon tank back then, I just topped it off.

With my current boat and its 29 gallon onboard tank, I guess I'll have to do the same thing. I know it has maybe 5 gallons in there now, so I'll add 10 or 15 gallons more, in 5 gallon increments, mixing as I go.

The gas tank fill doesn't have a long hose, just a short drop into the tank at the stern of the boat. It's a Perko plastic fill cap with built in ventilation.

My favorite lake is 40 miles away and my 2nd favorite lake is 25 miles distant, so self mixing while en route should be fine. 🤓

I can't see me sitting in a gas station, mixing up little batches of gas/oil and adding them to the tank while other folks wait around for me to get done. 🤪

Thanks for your thoughts and helping to jog my memory. 😎
 

racerone

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Dec 28, 2013
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Many marinas frown on those folks who fill fuel tanks in the slip to save $$$-----Something to do with liability and " gasoline handling " rules / regulations.----Gasoline spills are a big issue in a marina!
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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Use a 2-gallon tank. Mix that and prime the fuel system. This allows you to fire it up before the splash. Then add oil for the remainder of the tank capacity, and top off the tank at your local gas station. Then as you drive down the rough pot-hole infested roads....the rest will mix
 

cyclops222

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Mar 21, 2024
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Tests were done decades ago on how LITTLE of a oil to gas ratio could a 2 stroke engine run on at WOT.
BIG surprise. As little as 300 to 1 would not cause any noticeable wear.

BUTT BUTT
You know they REALLY MIXED the gas and oil .........Perfectly
None of the crappy put the gas in . Then add the oil.
Luck always can beat skill. For a while.
 

BWR1953

Admiral
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Jan 23, 2009
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How often do you run WOT?
I'm a bass fisherman, so pretty much WOT all the time when the engine is running. 😃

But, like most bass anglers, I go from spot to spot and then stop and use the electric trolling motor for the bulk of the day. During an 8 hour fishing day, the engine might only run for 10 or 15 minutes in total. 😏
 

cyclops222

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Mar 21, 2024
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I do the WOT on a regular basis if the fish are not biting during trolling for them. It perfectly cleans off all the carbon and oil on the plug.
 

jimmbo

Supreme Mariner
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May 24, 2004
Messages
13,438
Tests were done decades ago on how LITTLE of a oil to gas ratio could a 2 stroke engine run on at WOT.
BIG surprise. As little as 300 to 1 would not cause any noticeable wear.

BUTT BUTT
You know they REALLY MIXED the gas and oil .........Perfectly
None of the crappy put the gas in . Then add the oil.
Luck always can beat skill. For a while.
Actually, if the engine is completely Antifriction Bearing, including Piston Pin, it can survive running at idle with No Oil.
 

Chris1956

Supreme Mariner
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Mar 25, 2004
Messages
27,815
Jimmbo, You might want to correct your post to say that even idle requires some small amount of oil mixed into the gas for carb 2 cycle motors. If you have evidence of 2 cycle motors with carbs running on straight gasoline, I would like to see it.

Modern engines need 50::1 or maybe a bit leaner gas oil fuel to run at full throttle. If you run your 2 cycle carb engine on straight gasoline it will seize. No doubt about it.
 

jimmbo

Supreme Mariner
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May 24, 2004
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13,438
I will stand with that Statement. I had read about it several times back in the 70s
 
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