1985 115hp merc outboard

I have a 1985 mercury 115 hp outboard in which I hand mix the fuel and oil. After sitting for two years we took the boat out in S. Puget Sound. It started and ran great. Most of the time we were at half throttle, but opened it up several times to 43 mph. We landed it on the beach for an hour, started up and went about 2 miles to another beach with no problems. Upon shoving off to go back to the docks, it was hard to start and we had to go very slow. When opening up the throttle, it just died, so had to back off. When I got home to flush the motor, it was again hard to start and barely pumped out the water. I noticed that there was oil on the grass from the exhaust and a trickle of oil coming down the lower portion but I don't know where. Is my oil mix too rich. I use 50:1 but over the years the fuel may be too rich. I put it away until next Spring for now. Any suggestion?
Kent

Re: 1985 115hp merc outboard

Pump out that old fuel and run it in your lawn mower.

ALWAYS run fresh fuel with stabilizer (and oil). The stabilizer will help keep the fuel from souring for a few months, but much more than that, especially a couple of years, drain it and use fresh.

Spark plugs may be suspect after trying to burn that crud.

Re: 1985 115hp merc outboard

CharlieB said:

Pump out that old fuel and run it in your lawn mower.

ALWAYS run fresh fuel with stabilizer (and oil). The stabilizer will help keep the fuel from souring for a few months, but much more than that, especially a couple of years, drain it and use fresh.

Spark plugs may be suspect after trying to burn that crud.

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Thank you for the advice. I will drain the fuel and start fresh along with new plugs and the stabilizer.
Kent

Re: 1985 115hp merc outboard

Pre mix fuel is the worst to store. The gas and oil don't stay mixed well and the oil actually looses its abillity to lubricate. I am surprised that it even ran on 2 year old fuel. I wouldn't be surprised if the carbs weren't full of varnish as well as having a fouled plug.

Re: 1985 115hp merc outboard

Mercman, I am not sure where you get your info, but gas and oil stay very well mixed. They will never seperate. The oil also does not lose it's ability to lubricate.

The gas can get old and when it evaporates it can leave behind some varnish, and I therefore agree with your advise to check the carbs.

Re: 1985 115hp merc outboard

I use Stihl 50:1 mix oil at the house as I have a bunch already. But the stihl mix does have a form of sta bilt in it that preserves the fuel. And it does a good job of lubrication. The problem with ethanol and mix gas it it breaks down Dino oils thus reducing the lubrication properties. http://www.motorcycleaddicts.org/off-topic/35477-2stroke-fuel-mixing-storing.html#post255667

Sorry Chris I'm not the only one with this opinion. I have had 2 strokes since I was 8. Air cooled and water cooled. Any of the oil manufacturers recommend not storing more than what you can use in six months, the oil will not go bad by itself but when mixed it changes the characteristics of the oil.It's just not good practice to store premixed gas.

Chris1956 said:

Mercman, I am not sure where you get your info, but gas and oil stay very well mixed. They will never seperate. The oil also does not lose it's ability to lubricate.

The gas can get old and when it evaporates it can leave behind some varnish, and I therefore agree with your advise to check the carbs.

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Re: 1985 115hp merc outboard

I agree it is not good practice to store gasoline (mixed or not) for too long. However, gas and oil will stay mixed forever and the oil will lubricate just fine, after it is mixed, for as long as the gasoline is usable.