Switching 2 stroke for a 4 stroke, can I use mixed fuel left on tank on 4 stroke?

[dmas]

HI everbody

I'm upgrading from a 1989 Force 125HP 2 stroke motor to a 2003 Johnson 115HP 4 stroke, I sitll have a lot of mixed fuel left on my tank, should I empty the tank and flush it with fresh fuel or can I run the left over mixed fuel on my 4 stroke? could that cause any damage to the fuel inyection system? thanks.

Dan

 

[robert graham]

Re: Switching 2 stroke for a 4 stroke, can I use mixed fuel left on tank on 4 stroke?

You can probably do it, but it may smoke some. If it was mine I'd find some other use for that gas/oil mix and fill the tank with fresh gas. Good Luck!

 

[jeff_smith_0423]

Re: Switching 2 stroke for a 4 stroke, can I use mixed fuel left on tank on 4 stroke?

Those evinzuki's are pretty tough but I don't know about this. I run 50/1 out of my boat tanks in my Kohler motors, weed eater, blower, etc, but with as big of an outlay as an outboard, i probably wouldn't do it.

I would expect the first thing that would happen is that your fuel/water separator will get clogged with oil.

If you're going to do it, at least dilute what's in the tank 50/50 with good, fresh, non-ethanol fuel.

I would think the cost of dumping your old fuel would be way less than the repair bill!

 

[Jamie-C]

Re: Switching 2 stroke for a 4 stroke, can I use mixed fuel left on tank on 4 stroke?

I don't know much about this but if I'm honest I would just dump the fuel to be on safe side.

 

[surge006]

Re: Switching 2 stroke for a 4 stroke, can I use mixed fuel left on tank on 4 stroke?

i know pretty much enough about motorcycles and dirt bikes and you DO NOT want to use pre mix fuel in a 4 stroke for the cost of new fuel vs a new motor its not worth it

 

[Tig]

Re: Switching 2 stroke for a 4 stroke, can I use mixed fuel left on tank on 4 stroke?

At the end of the season I often burn a few gallons of left over mixed fuel in a car, truck or what ever. Trolling or idling for long periods with mixed gas in a four stroke may foul the plugs. Running mixed gas all season might cause excess deposits. As mentioned dilute it as much as possible. I usually mix with 3/4 fresh gas and I've never noticed a difference in how the engine runs or smells.
How big is your tank and how much mixed fuel is in it?
Fuel filter specs do not change from two to four stoke engines.
If anyone can explain a technical reason to not do this I'm all ears.
I think a bit of extra lube on the valves and fuel pump would be good. Cylinders have trace amounts of oil so no harm there either.

 

[ondarvr]

Re: Switching 2 stroke for a 4 stroke, can I use mixed fuel left on tank on 4 stroke?

It will make no noticable difference, just fill the tank up and run it, one tank will have zero effect on anything.

 

[dmas]

Re: Switching 2 stroke for a 4 stroke, can I use mixed fuel left on tank on 4 stroke?

thanks guys for your replys, I got about a quarter tank left of mixed fuel and I was planning on doing what you guys said, fill up the tank up with fresh fuel to dilute the mix or empy the mix to a couple of plastic containers, but if what it does is only create some smoke I would rather dilute the mix with fresh fuel.

I was concerned about the fuel inyectors getting clogged, since parts aren't cheap on this engine.

 

[scipper77]

Re: Switching 2 stroke for a 4 stroke, can I use mixed fuel left on tank on 4 stroke?

I would absolutely not use it. I'm sure the combustion chamber on wouldn't care about a little oil. I mean how many old cars burn oil at a rate that's got to be equivalent to a 100:1 ratio. But like you I'd worry about my injectors. The way I see it injectors last a "really" long time compared to a carb, but they aren't cheap to replace. Why jeopardize them?

 

[WIMUSKY]

Re: Switching 2 stroke for a 4 stroke, can I use mixed fuel left on tank on 4 stroke?

At the end of the season I often burn a few gallons of left over mixed fuel in a car, truck or what ever.

I do the same thing with leftover string trimmer/leaf blower gas. I dump it in my truck. As far as your outboard, you can probably get away with using it, but if it were me, I wouldn't. Dump it in your car/truck. Just my opinion.

 

[ondarvr]

Re: Switching 2 stroke for a 4 stroke, can I use mixed fuel left on tank on 4 stroke?

So tell me what a 200-1 oil mix is going to do to an injector to destroy it....nothing, it won't even know its there.

Just run the stuff.

 

[Cricket Too]

Re: Switching 2 stroke for a 4 stroke, can I use mixed fuel left on tank on 4 stroke?

You're not gonna have any problem if you fill up and dilute it that much...it won't do a thing. I've put fogging oil through injectors to winterize engines, 2stroke aint gonna do a thing, fill up and go enjoy it.

If won't have any affect on injectors or any filters. Fuel water separators are the same for any engine, they separate fuel and water, they don't care what kind of engine they do it for.

 

[coolguy147]

Re: Switching 2 stroke for a 4 stroke, can I use mixed fuel left on tank on 4 stroke?

dilute dilute dilute and dilute some more

then do a nice decarb

 

[rodbolt]

Re: Switching 2 stroke for a 4 stroke, can I use mixed fuel left on tank on 4 stroke?

as long as the left over 2 stroke fuel is clean and fresh, clean and fresh, clean and fresh.
you wont have any issues, infact we use a 24/1 mix when winterizing merccruisers,volvos and EFI four stroke yamahas to aid in keeping pumps and injector pintles from sticking over long term storage.
notice I asked if the remaning fuel was clean and fresh?

 

[kenmyfam]

Re: Switching 2 stroke for a 4 stroke, can I use mixed fuel left on tank on 4 stroke?

Completely agree. The existing fuel must not be stale. Top off the tank as often as you can with unmixed gas to get the oil ratio lower sooner and you should not have any issues.
Been using 2 stroke mix in the mower for years.
My 2 cents.

 

[dmas]

Re: Switching 2 stroke for a 4 stroke, can I use mixed fuel left on tank on 4 stroke?

thanks for you help guys, I ended up removing 99% of the 2 stroke fuel and filled it up with fresh fuel and btw, is working great.

 

[The Hammer]

Re: Switching 2 stroke for a 4 stroke, can I use mixed fuel left on tank on 4 stroke?

If will foul up your plugs badly.

 

[bigrockets]

Re: Switching 2 stroke for a 4 stroke, can I use mixed fuel left on tank on 4 stroke?

If you're truck or car has a catalytic converter don't dump the leftover mix in the vehicle. Nothing kills a cat faster than oil. You should be able to dilute it with no harm to the engine or you can trade all of your friends and neighbors with weedwackers and leaf blowers to a tank of gas in return for a can or two of beer.

 

[RicMic]

Re: Switching 2 stroke for a 4 stroke, can I use mixed fuel left on tank on 4 stroke?

Amazing, its OK to burn it in a two stroke, without it hurting anything, but people think it will do all kinds of bad things in a four stroke? Whats the difference? If it dosn't carbon up anything in one, why would it do it in the other? There's nothing magic there. People run DOUBLE oil in their two strokes all the time and never even realize it and it dosn't hurt anything.

 

[The Hammer]

Re: Switching 2 stroke for a 4 stroke, can I use mixed fuel left on tank on 4 stroke?

Don't know the answer to that RicMic. I had about a gallon of leftover 50:1 from my boat and tried to use it in my 4 stroke Lawn Boy, about 20 minutes it quits, I pull the plug and it is coked right up so I clean it and reinstall again 20 mins later same thing so I returned to straight gas and it doesn't do it now.