2 stroke piston ring health??
 

Any of you folks ever ruin an outboard because of stuck rings or carbon
under the rings?

Was it from long hours of low speed trolling or high speed use?

I tend to run my engine at 40:1 with OMC XD30 and I was wondering if
perhaps that is bad for my rings compared to 50:1 mix. I run the engine
pretty hard pulling a skier often, amounting to about 50% of the engine
hours. I can turn the engine easy enough with my hands on the flywheel
and the compression is balanced at about 120 each. I am really just
trying to get the most life out of this motor and not hurt it.

The motor is a 1981 3cyl 70hp Evinrude.

Anyone want to share "wish I wouldn't have done that" stories?

TNX guys

I think your 40:1 makes sense for hard running. Back in the '70's we used
to run 24:1 in our dirt bikes. Just remember, heavy oil mix takes away some
from your fuel. Too much oil will make it run lean (since the oil doesn't
burn, it takes the place of the gas). If your plugs look good,
compression's good, my bet would be to do exactly as you are. I troll a lot
with my 200 merc and do tend to foul the plugs somewhat (with 50:1).
LD

"Gudmundur" wrote in message
...
Any of you folks ever ruin an outboard because of stuck rings or carbon
under the rings?

Was it from long hours of low speed trolling or high speed use?

I tend to run my engine at 40:1 with OMC XD30 and I was wondering if
perhaps that is bad for my rings compared to 50:1 mix. I run the engine
pretty hard pulling a skier often, amounting to about 50% of the engine
hours. I can turn the engine easy enough with my hands on the flywheel
and the compression is balanced at about 120 each. I am really just
trying to get the most life out of this motor and not hurt it.

The motor is a 1981 3cyl 70hp Evinrude.

Anyone want to share "wish I wouldn't have done that" stories?

TNX guys

Running it hard tends will keep it cleaner that trolling. 2 strokes are
more prone to carbon build up. Just their nature.

"Gudmundur" wrote in message
...
Any of you folks ever ruin an outboard because of stuck rings or carbon
under the rings?

Was it from long hours of low speed trolling or high speed use?

I tend to run my engine at 40:1 with OMC XD30 and I was wondering if
perhaps that is bad for my rings compared to 50:1 mix. I run the engine
pretty hard pulling a skier often, amounting to about 50% of the engine
hours. I can turn the engine easy enough with my hands on the flywheel
and the compression is balanced at about 120 each. I am really just
trying to get the most life out of this motor and not hurt it.

The motor is a 1981 3cyl 70hp Evinrude.

Anyone want to share "wish I wouldn't have done that" stories?

TNX guys

"JamesgangNC" wrote in message
.net...
Running it hard tends will keep it cleaner that trolling. 2 strokes are
more prone to carbon build up. Just their nature.

"Gudmundur" wrote in message
...
Any of you folks ever ruin an outboard because of stuck rings or carbon
under the rings?

Was it from long hours of low speed trolling or high speed use?

I tend to run my engine at 40:1 with OMC XD30 and I was wondering if
perhaps that is bad for my rings compared to 50:1 mix. I run the engine
pretty hard pulling a skier often, amounting to about 50% of the engine
hours. I can turn the engine easy enough with my hands on the flywheel
and the compression is balanced at about 120 each. I am really just
trying to get the most life out of this motor and not hurt it.

The motor is a 1981 3cyl 70hp Evinrude.

Anyone want to share "wish I wouldn't have done that" stories?

TNX guys


Most of the engine damage I've seen is always because one of the carbs was
not working. Running your engine with one carb clogged causes the cyl to
run dry. This damages the rings/cyl on one or more cyls. Sometimes it's
hard to not limp in on one carb (safety reasons).

When I get a missing or dead cyl I stop and check for spark. If I have none
I feel it's safe to limp home. IF the cyl has spark I pull the plug and if
dry call for a tow. It's better to pay the $150 than to total an engine.

Most of the engine damage I've seen is always because one of the carbs was
not working. Running your engine with one carb clogged causes the cyl to
run dry. This damages the rings/cyl on one or more cyls. Sometimes it's
hard to not limp in on one carb (safety reasons).

When I get a missing or dead cyl I stop and check for spark. If I have none
I feel it's safe to limp home. IF the cyl has spark I pull the plug and if
dry call for a tow. It's better to pay the $150 than to total an engine.


I never thought about that, but it makes sense. No matter how clean
I try to keep the system there is always something down there sloshing
around in the fuel. I could see where a stuck float or dirt causing a
cylinder to drop would also kill the available lubrication and end up
with a wrecked engine. All the better reason to pull my system down and
look closer this fall in preparation for the coming spring.