2 stroke fuel for 4 stroke engine?

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NormanS

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I have a 2.5hp Mariner 2 stroke outboard, which uses a 50:1 mix. I also have a 1000w 4 stroke petrol generator, which lives in a locker, "just in case". Realistically, I think I have used it once in the last four years. It means that I have two 5 litre petrol containers, lurking in the aft locker. Would I get away with running the 4 stroke on the two stroke mix, or would it oil the plug etc?

The alternative would be to use a much smaller container for the pure petrol, maybe 1 litre, but it would be simpler if I could get away with just the one container for both engines. What does the team think?
 
NormanS said:
I have a 2.5hp Mariner 2 stroke outboard, which uses a 50:1 mix. I also have a 1000w 4 stroke petrol generator, which lives in a locker, "just in case". Realistically, I think I have used it once in the last four years. It means that I have two 5 litre petrol containers, lurking in the aft locker. Would I get away with running the 4 stroke on the two stroke mix, or would it oil the plug etc?

The alternative would be to use a much smaller container for the pure petrol, maybe 1 litre, but it would be simpler if I could get away with just the one container for both engines. What does the team think?
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You dont want to keep two can of petrol going stale or taking up valuable space

Just keep one , without oil , and mix the fuel for the Mariner, say 1/2 tank full at a time, as required.

That's how I manage the need for two different 2 stroke mixes. Both on the boat for two different outboards and at home for different items of garden machinery

I use plastic laboratory conical measures for measuring the oil and plastic jugs for the petrol when necessary
 
IMHO, a small ratio of oil, like 50:1 will not adversely affect a 4 stroke engine while it is running. The idea that it affects the lean/rich balance of the carb does not stand analysis.
Letting peroil mix evaporate in the carb of a small 4stroke might not be a good idea.
Lots of idling or light running of a cold 4stoke on oil mix might oil the plug.

Personally, when I need some fuel for a small 4 stroke, I just syphon it from my motorbike though.

Main thing IMHO is to avoid keeping more petrol than you need to, and to keep it in sealed containers not vented fuel tanks.
 
I've used the Honda fuel treatment for the petrol in my Honda 2.3 Seems to keep the fuel ok, I serviced it a couple of days ago and it started 2nd pull with the remains of the fuel from last year. For the 2 T engines I have at home I just mix it in a separate can, about 3 litres does me for a year, and I add a bit of the Honda additive.
 
Thanks for all the suggestions and comments. Obviously there are a few options. I'll have a think about it.
 
I have put 2 stroke in a 4 stroke mower and it kicked out a serious amount of smoke.
The garden looked like a re-enactment of the opening exchanges in the battle of Jutland.
 
doug748 said:
I have put 2 stroke in a 4 stroke mower and it kicked out a serious amount of smoke.
The garden looked like a re-enactment of the opening exchanges in the battle of Jutland.
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I have used 50/1 2 stroke mix in a 2hp honda 4 stroke. Didn't particular smoke or lose power . It's more critical to use fresh fuel either in 4 or 2 stroke. If it's a new Honda genny you will struggle to start it. If it does start you stand more chance of damage by stale fuel than a 2 stroke mix
 
There's no way that a mixture weakened by 2-stroke oil at 50:1 will cause problems in a generator donk. A drop in atmospheric pressure of only 20mb will give the same effect. I doubt many boaters consult their barometer (and humidity gauge) before firing up the gennie.

But that doesn't make petroil in a 4-stroke a good idea.
 
My view FWIW is that it won't make any difference- might even do it some good. In the bad old days we used to use upper cylinder lubricant, aka Redex, to keep everything running sweetly and it worked just fine. Just try it. Won't blow anything up that's for sure.......

PS I always put my leftover 2 stroke in the wife's VW every Spring, never had a problem.
 
sparkie said:
My view FWIW is that it won't make any difference- might even do it some good. In the bad old days we used to use upper cylinder lubricant, aka Redex, to keep everything running sweetly and it worked just fine. Just try it. Won't blow anything up that's for sure.......

PS I always put my leftover 2 stroke in the wife's VW every Spring, never had a problem.
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But Redex was only used at a dose rate of 10ml per 10 litres. That's a twentieth of the amount of oil in a typical 2 stroke outboard mix
 
I've always used up end of season surplus 50;1 mixture in my Honda 4 stroke mower. Never any problem in starting or running and no visible exhaust smoke. I gave the old mower way when eventually the base plate corroded through.
 
Absolutly-in practice, no problem.

When I was an impecunious young bike racer the race bike fuel tanks were drained and poured into the Morris Minor van or the Commer and neither had any ill effects. When not lugging the race bikes both vans were often used for commuting.

The Castor oil invariably used in the two stroke bikes made the exhaust's smell lovely.................
 
NormanS said:
I have a 2.5hp Mariner 2 stroke outboard, which uses a 50:1 mix. I also have a 1000w 4 stroke petrol generator, which lives in a locker, "just in case". Realistically, I think I have used it once in the last four years. It means that I have two 5 litre petrol containers, lurking in the aft locker. Would I get away with running the 4 stroke on the two stroke mix, or would it oil the plug etc?

The alternative would be to use a much smaller container for the pure petrol, maybe 1 litre, but it would be simpler if I could get away with just the one container for both engines. What does the team think?
Click to expand...

For my our boat's outboard, I tend to buy 5l of fuel.
So I have one can which never has any oil in it. I keep a second can, to which I add oil.
When the oiled can runs out, I mix 5 litres in the '2T' can, then put the empty 'no oil' can aside to be refilled at my leisure. So, we are never (in theory) caught with not enough fuel for the outboard.
I have found several times that having a couple of cans of diesel and a can of fresh-ish unadulterated unleaded on board has been very useful. To other people that is!
Being able to let other people have a few litres of fuel when they needed it might mean I feel less silly asking some other stranger for a favour.
 
It eventually fouls the plug, my Honda generator was fine for ages on 2stroke then started giving some impressive backfires and flames out the exhaust
 
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