Outboard Motor Help

[Liam Wald]

I have a 4 stroke Yamaha 2.5hp. It has approximately 30 hours since new. It always ran just fine, although it hadn't been run in two years. I changed the oil. To do so I took it home. I also drained the gas and refilled with fresh fuel. After I took it back to the boat it wouldn't start. I left it at the boat but forgot to close the fuel cock. I brought it home again and discovered that there was fuel in the crankcase oil.
I drained the crankcase and put in new oil. I took the spark plug out and found that there was fuel and oil in the cylinder. I cleaned the spark plug and tried to drain the cylinder.
I replaced the spark plug and tried to start it up. It starts but will only run about 5 seconds and then stops. It will do this over and over again. Lots of smoke like it is burning oil.
I am thinking I should remove the spark plug again, try to flush the cylinder with alcohol to remove any oil residue and then install a new spark plug.
Any help would be greatly appreciated.

[Kettlewell]

My guess is that your carburetor is gummed up and needs a good cleaning. The float might be sticking allowing too much fuel to run into the engine, which is seriously flooding it. First take off and clean the carburetor thoroughly. You may want to get the rebuild kit, though I find in general a soak and clean does the trick. Pay careful attention to the tiny passages where fuel needs to flow, particularly the jets. Don't run anything through the jet or they can be damaged. You can use compressed air or something like the spray nozzle on a can of WD40 to squirt through the jets to help clean them. The spark plug will need to be pulled and dried and cleaned of oil, but don't put alcohol into the cylinder. When the spark plug is out pull over the motor a few times to pump out any wet fuel that may still be in there. I put marine StaBil (the blue stuff) in every tank of gas that goes through my outboards to help guard against the carb. plugging up.

One trick I do is to disassemble the carb. while it is within something like a dishpan so that I don't lose any of the tiny parts that inevitably fall out.

[DeborahLee]

The reason you are getting gas in the oil is you are laying it down on its side with the handle up. The oil drains thru carb. Had a 2.5 and did the same thing then read the book, just didn't seem right laying it on the handle. Another problem that could be causing your starting problem is the fuel filter is clogged. It is in the bottom of the fuel tank. All you have to do is wash it off with some dish detergent. Mine clogged several times once it left us hanging on to an anchor rode in a strong current. Finally took it out and put a bigger in-line filter that I could get to.

[Liam Wald]

Originally Posted by DeborahLee

The reason you are getting gas in the oil is you are laying it down on its side with the handle up. The oil drains thru carb. Had a 2.5 and did the same thing then read the book, just didn't seem right laying it on the handle. Another problem that could be causing your starting problem is the fuel filter is clogged. It is in the bottom of the fuel tank. All you have to do is wash it off with some dish detergent. Mine clogged several times once it left us hanging on to an anchor rode in a strong current. Finally took it out and put a bigger in-line filter that I could get to.

Thanks Deborah.
Yes, seems counter intuitive to lay the motor on the handle. I saw that in the book although too late.
So the fuel filter is inside the fuel tank???
I will look for it and clean as you recomend.
Thanks again.

[rwidman]

Originally Posted by Liam Wald

...........
I am thinking I should remove the spark plug again, try to flush the cylinder with alcohol to remove any oil residue and then install a new spark plug..

I don't think alcohol is a solvent for oil, but in any event, I would not put anything in the cylinder that doesn't belong there.

[rwidman]

Originally Posted by Liam Wald

Thanks Deborah.
Yes, seems counter intuitive to lay the motor on the handle. I saw that in the book although too late..

It's funny how reading the book changes things.

[Liam Wald]

Originally Posted by rwidman

It's funny how reading the book changes things.

You are absolutely correct. Admittedly, this is one of my shortcomings. Other than a cursory once over I seldom read owners manuals before things go awry.
Who would have thought that laying an outboard on it's side would cause the oil to leak through the carb and into the cylinder.

Not trying to be defensive, but it would also have been nice of Yamaha to instead of just telling you how to lay the engine down, tell you why.
Maybe in big bold or italic letters something like, "Because of our crappy design, lying your engine in any way other that described will cause the crank case oil to leak into the cylinder and then require some serious attention."

[rwidman]

Originally Posted by Liam Wald

You are absolutely correct. Admittedly, this is one of my shortcomings. Other than a cursory once over I seldom read owners manuals before things go awry.
Who would have thought that laying an outboard on it's side would cause the oil to leak through the carb and into the cylinder.

Not trying to be defensive, but it would also have been nice of Yamaha to instead of just telling you how to lay the engine down, tell you why.
Maybe in big bold or italic letters something like, "Because of our crappy design, lying your engine in any way other that described will cause the crank case oil to leak into the cylinder and then require some serious attention."

It's not just Yamaha and it's not a "crappy design". If you think of a cross section of a four stroke gasoline engine, the cylinder and piston are on one end, the crankcase and oil pan are on the other. The engine is on its side in normal operation. Lay it down the correct way and the piston is on top, the crank case on the bottom. Lay it the other way and the oil filled crank case is on top and oil leaks down whatever way it can.

[Liam Wald]

Originally Posted by rwidman

It's not just Yamaha and it's not a "crappy design". If you think of a cross section of a four stroke gasoline engine, the cylinder and piston are on one end, the crankcase and oil pan are on the other. The engine is on its side in normal operation. Lay it down the correct way and the piston is on top, the crank case on the bottom. Lay it the other way and the oil filled crank case is on top and oil leaks down whatever way it can.

Makes sense. Thanks.

[Stu Jackson]

Originally Posted by Liam Wald

, this is one of my shortcomings. Other than a cursory once over I seldom read owners manuals before things go awry.

Not trying to be defensive, but it would also have been nice of Yamaha to instead of just telling you how to lay the engine down, tell you why.
Maybe in big bold or italic letters something like, "Because of our crappy design, lying your engine in any way other that described will cause the crank case oil to leak into the cylinder and then require some serious attention."

Uhm, if ya didn't rtfm to begin with, what difference would it make?

[SkiprJohn]

Four strokes are very much unlike two strokes in the position they can be carried and stored as you've determined.
Both engines should not be stored in any position with E-10 or any kind of ethanol fuel in tank, lines or carb.. I run mine dry after each use. It's the only thing that keeps me from having to clean/rebuild the carb each time I store them for a few months. Luckily there is a new service station within 6 miles that sells non-ethanol fuel so I can safely use it in outboards, weedwhackers and chainsaws although I still run them dry after each use just to be certain.
The Fed and State government has done us no favors by requiring E-10 fuel.
kind regards,

[rwidman]

Originally Posted by SkiprJohn

Four strokes are very much unlike two strokes in the position they can be carried and stored as you've determined.
Both engines should not be stored in any position with E-10 or any kind of ethanol fuel in tank, lines or carb.. I run mine dry after each use. It's the only thing that keeps me from having to clean/rebuild the carb each time I store them for a few months. Luckily there is a new service station within 6 miles that sells non-ethanol fuel so I can safely use it in outboards, weedwhackers and chainsaws although I still run them dry after each use just to be certain.
The Fed and State government has done us no favors by requiring E-10 fuel.
kind regards,

It's just not practical to drain the fuel after each use. At the end of the season perhaps, or before a period of non use, but not after every trip ashore. Modern engines are designed for E10 fuel.

I share your distain for E 10 and regulations, but we must either live with them, work around them, or move to a third world country where the government doesn't care about these things.

BTW: My Honda has little feet on the side that's supposed to be down when in storage.

[DeborahLee]

The fuel line goes right on the end of the filter. It is about 1/4" in dia and 1" long white plastic. You probably won't see anything on it. It gets a clear coating of something from our new and improved fuel. The dish detergent will dissolve it. Usually no warning when it decides to kill the engine. If that doesn't do it then its the carb, try fuel bowl and needle valve. Good luck I had a love hate relationship with mine.

[DeborahLee]

If you go into the carb be careful of the throttle cable. On mine the end wasn't soldered and it frayed making it hard to put back on the carb. Finally hard to replace it. Strange thing though the replacement cable from Yamaha had the end soldered imagine that and it wasn't cheap.

[SkiprJohn]

Originally Posted by rwidman

It's just not practical to drain the fuel after each use. At the end of the season perhaps, or before a period of non use, but not after every trip ashore. Modern engines are designed for E10 fuel.

I share your distain for E 10 and regulations, but we must either live with them, work around them, or move to a third world country where the government doesn't care about these things.

BTW: My Honda has little feet on the side that's supposed to be down when in storage.

What you are describing is an engine with a built in tank and no fuel shut off? If it has a fuel shut off valve just turn it closed and run the fuel out of the carb. The carb is where most the junk builds up. Very gooey mess if you've ever seen it. It does not disolve in carb cleaner. Nasty stuff.

kind regards,