Honda 9.9 burning oil

[maineiac5586]

New to me 2008 9.9
Can't get it to accelerate without big bog that will kill the motor if not turning back throttle to idle. If you turn throttle slowly it will rev up but blowing smoke out exhaust. I cleaned carb thoroughly. Found engine oil in airbox on that screen looking part. Pulled spark plugs I think they are oily. Put camera down plug holes pistons look a little wet to me. Crosshatch still good. What do you think of these plugs? Oily? What to do next?

 

[dingbat]

New to me 2008 9.9
Can't get it to accelerate without big bog that will kill the motor if not turning back throttle to idle. If you turn throttle slowly it will rev up but blowing smoke out exhaust. I cleaned carb thoroughly. Found engine oil in airbox on that screen looking part. Pulled spark plugs I think they are oily. Put camera down plug holes pistons look a little wet to me. Crosshatch still good. What do you think of these plugs? Oily? What to do next?

Oily for a properly tuned and operating 4 stroke

Guessing the “smoke” is excess fuel. Either the carbs are out of adjustment or the ignition module is having issues

 

[maineiac5586]

Oily for a properly tuned and operating 4 stroke

Guessing the “smoke” is excess fuel. Either the carbs are out of adjustment or the ignition module is having issues

Why don't you think it's burning oil? What about the fresh oil I'm finding in the breather hose and airbox screen?

 

[dingbat]

Why don't you think it's burning oil? What about the fresh oil I'm finding in the breather hose and airbox screen?

How does oil get from the combustion chamber to the air box?

Compression numbers?

Spark test?

Complete disassembly and cleaning of the carbs?

Checked timing?

 

[cyclops222]

Vacuum leak / leaks along the intake manifold ?

 

[racerone]

Replace seals on valve stems.----Test / inspect thermostat.

 

[maineiac5586]

Replace seals on valve stems.----Test / inspect thermostat.

Thanks. Know of any good write up about how to do the valve seals? Why the thermostat test?

 

[maineiac5586]

Is this similar to a car where I can pressurize the cylinder through the spark plug hole then change seals? No need to pull cylinder head right?

 

[MattFL]

The crank case breather might be run to the airbox, that's common on 4-strokes. Some ideas to check: if the oil is too full, it can pass oil through the breather to the airbox. If the motor was stored in the wrong position (laying on the wrong side) oil can get into the breather and into the airbox. If it has ever over heated, that can cause the oil control rings on the piston to loose their springiness and it can start burning oil. The bog problem is unlikely to be related to the oil.

Since it's new to you, here's what I would do if it were mine. Disassemble and clean the carburetors surgically clean. Air and carburetor cleaner through every hole, use an ultrasonic cleaner if you have one. This will likely cure the bog. Change fuel filter, the oil and oil filter if it has one, make sure the oil is not too full. Put a new water pump impeller and thermostat in it to be sure it won't overheat (since it's new to you and those are standard wear parts). Take it out and run it, give it a good hard running. Now that it's running correctly, re-evaluate the oil burning situation.

 

[maineiac5586]

The crank case breather might be run to the airbox, that's common on 4-strokes. Some ideas to check: if the oil is too full, it can pass oil through the breather to the airbox. If the motor was stored in the wrong position (laying on the wrong side) oil can get into the breather and into the airbox. If it has ever over heated, that can cause the oil control rings on the piston to loose their springiness and it can start burning oil. The bog problem is unlikely to be related to the oil.

Since it's new to you, here's what I would do if it were mine. Disassemble and clean the carburetors surgically clean. Air and carburetor cleaner through every hole, use an ultrasonic cleaner if you have one. This will likely cure the bog. Change fuel filter, the oil and oil filter if it has one, make sure the oil is not too full. Put a new water pump impeller and thermostat in it to be sure it won't overheat (since it's new to you and those are standard wear parts). Take it out and run it, give it a good hard running. Now that it's running correctly, re-evaluate the oil burning situation.

Yes it is good to go. Ultrasonic cleaned carb got rid of bog. Oil issue gone. I think former owner stored it on the wrong side. Thanks for everyone's help