I recently replaced an old 2 stroke Johnson with a newer 4 stroke Johnson. Fuel is mixed with oil as I did not use VRO. Is it safe to run the fuel/oil mix through the 4 stroke. I’m concerned about fouling the plugs or injectors. Who can pump out the old fuel. Thanks
quote:
Originally posted by WaterbreakerI recently replaced an old 2 stroke Johnson with a newer 4 stroke Johnson. Fuel is mixed with oil as I did not use VRO. Is it safe to run the fuel/oil mix through the 4 stroke. I’m concerned about fouling the plugs or injectors. Who can pump out the old fuel. Thanks
You do not want to run the oil gas mix if you can help it. To drain it, take your hose off after the primer bulb and put a piece of hose on it that will put the end below the bottom of the tank. Prime to get fuel flowing and make a siphon.
I don’t know where you are, but I have a 12 volt gas pump you can use if you cannot siphon it out.
Looking for 21-24 bay or deep V boat
I have run a lot of Chevy trucks on pre-mix – never had a problem. Explanation: Had a lawn business and the only fuel I carried was pre-mix for the weed wacker…
owned by trailer bearings…
How much fuel are you talking about? Can’t see any harm in adding 5 gallons of premix to a tank of gas in an old PU! I have 2, 55 gallon drums of old ethanal gas sitting in my garage now. I’ll run it in lawn equipment, but won’t run it in anything with injectors! Like MattR said, take the gas line loose from your first connection after the tank and extend it to go out of the boat. Make some sort of siphon and drain it into something. Don’t run the fuel through any filters like a water/fuel seperator when you drain it. The problem is if your tank has a top feed tube on it. The feed tube does not go all the way to the bottom of the tank, so you are still going to have gas in the tank. I have a 12 volt in-line fuel pump I got at an auto parts store. I mounted it to a short board and attached hoses to it. Hook the pump up to your boat battery with some long wires and gater clips and start pumping.
quote:
Originally posted by 192GradyI have run a lot of Chevy trucks on pre-mix – never had a problem. Explanation: Had a lawn business and the only fuel I carried was pre-mix for the weed wacker…
owned by trailer bearings…
Old Chevy “tree fiddy” will run on a mix of chicken urine and turpentine. 
I loved my old chevys.
Depending on the engine, oil mixture, and remaining oil, it probably will not hurt it. The oil will build carbon at a high rate. Carbon and high compression is a recipe for pre ignition. Preignition will tear a motor apart quickly. (350 has a knock sensor to retard timing to help with preignition, lots of 4 stroke outboards do not)
So, if its 5 gallons of premix 50-1 to 15 gallons of gas, run it. If its 5 gallons of 32-1 and 5 gallons of gas, I would pump it.
Looking for 21-24 bay or deep V boat
I’d drain the tank. If you can take the fuel line directly from the tank (before the filter) and run it through the drain hole in the bilge you will be at the lowest point in the boat. Have a container ready and sometimes gravity will do all the work. If fuel line is too short buy a couple of feet of clear tubing and a double end barbed connection from any hardware store. Connect the clear tube to the fuel line and though the drain hole. If it doesn’t drain by itself siphon it. It’s pretty simple, cost less than 5 bucks.
Run it you be fine once ran 12gal of 50/1in my 4.8 Chevy when the boat was down and the wallet was thin
fish today work tomorrow
If you insist on running the old fuel through the 4 strk then you should fill the tank w/ fresh gas to at least dilute the oil mixture.
it will burn it, but its not gonna like it
it can easily foul the plugs, then sensor are going to set codes and its gonna run bad