crankcase oil fill and drain on force?

[jmoracco]

hello everyone! new to the boating world and have a weird question. i have a 1986 force 125 outboard 2stroke. i changed lower unit oil, but where the heck or how do you change the crankcase oil, know the bottom end of the motor has to get lubricated from somewhere. i just cant figure how. does the lower unit oil get forced up there somehow? if anyone can help my ignorance it would be greatly, greatly appreatiated! i just ordered a manual but wont be here for a week.

 

[roscoe]

Re: crankcase oil fill and drain on force?

Welcome to iboats.

Hopefully your manual is a Clymer manual.
There is some good reading in it for you.

The Seloc manual is not very good.
It will explain how a 2 stroke motor works.

2 stroke motor.
That means you need to mix 2.6 ounces of oil with each gallon of gasoline.
Use any TCW-3 rated oil.

That is where the "crankcase" (powerhead) gets its lubrication.
You forget to mix the oil in the fuel, you engine blows up in a very short amount of time.

The lube in the lower unit is sealed in there.
Make sure you used a marine grade gearcase lube.

Don't be afraid to ask questions.

 

[Silvertip]

Re: crankcase oil fill and drain on force?

The reason there is no "sump" (also called an oil pan) on your engine is because your engine is a two-stroke, not a four-stroke like a car engine. Oil is mixed with the fuel at the carbs, and sucked into the crankcase under vacuum as the piston for each cylinder rises. When the piston fires and begins its downward stroke, the reed valves close to prevent the fuel/oil charge from being blown back out the carb so the area that was under vacuum before, is now under pressure. The piston uncovers a port in the cylinder and the pressurized fuel/oil mix enters the cylinder and the piston rises again closing that port and compressing the fuel/oil charge. It goes bank and the process starts all over again (very quickly). While the fuel/oil charge is in the crankcase, the roller bearings are lubriced by the oil in the fuel. Unlike a four-stroke, the crankcase for each cylinder is sealed from the others.

 

[jmoracco]

Re: crankcase oil fill and drain on force?

thanks so much guys! i do understand now. you guys explained perfectly. for the lower unit, i used mobil one synthetic gearlube. not marine grade but i was told that it would work good, is this correct you think or should i just drain and refill with marine grade lube? thanks once again guys!
one more thing; the boat i purchased was sitting and rotting for the last five years. i think that i got lucky with the motor still being good, mainly due to low hours, and it does have a new impeller. runs good. the boat is a 17.10 bayliner capri and im going to do some fiberglass work, luckily i work with a fiberglass guy,but was woundering by any chance if anyone has had to refurbish the transom area, the bolts mounting the motor have pulled thru the inner fiberglass of the boat and is rotten around that area, can i cut inner fiber glass out clean up and stick a new piece of plywood in and fiberglass the crap out of it, without redoing the whole rear section of the boat. or am i doomed to redo the whole thing. thanks again! by the way if anyone has pics of there boats i would realy like to see them to admire and maybe get some new interior ideas.

 

[roscoe]

Re: crankcase oil fill and drain on force?

Marine grade gearlube is made to work, even if the seals on the lower unit fail, and allow water to enter.
In the event of water intrusion, the water will mix with the lube and the lube will still provide corrosion protection for the gears.
I don't know what your mobil one will do.

As for the transom repair, it is important to remove all wet and rotted or damaged wood and glass. Also to remove any glass that has separated from the wood. Otherwise you are wasting your time.

You will find plenty of info in the boat restoration forums.

http://forums.iboats.com/forumdisplay.php?s=&daysprune=-1&f=22


http://forums.iboats.com/forumdisplay.php?s=&daysprune=-1&f=407