Honda GX690 24HP burning through oil after overfilling with oil. Is this a Breather Valve issue?

[Flankyou7]

One of my crew members put too much oil in the engine. We have drained the oil, replaced the plugs and air filter since. However this engine is eating oil like crazy. You can smell the burning oil in the exhaust, but there isn't "white smoke" so to speak as we run the machine.

I'm trying to figure out what is basically so saturated in oil, this engine can't breath and is eating oil.

Is is a breather valve issue?
Anyone know where is the breather valve is on these engines (I believe there is a small screen it's buried on the backside and I'll have to pull the engine to get to it) Could that screen be causing this?

How do I check crankcase pressure? That is what I am assuming is causing the engine to burn through oil.

Thanks in advance for any help.

 

[wag123]

The muffler is likely full of oil. If you have drained the oil down to where it is not overfull now, just run it until it stops smoking. It might take awhile.

 

[Flankyou7]

Been running it for over 2 months since the kid overfilled it. We are just adding oil as we go.
It's not putting out heavy white smoke one would see with too much oil.

It's just burning through oil like crazy since this overfill

The engine is less than 2 years old. Only has 283 hours on it

 

[kschachn]

What's the exact definition of "eating oil" and "burning through oil like crazy"?

 

[wag123]

I misunderstood your problem, sorry.
There is a crankcase breather between the cylinders behind the flywheel. The breather cover is triangular shaped and held on with 3 bolts (#2 in the diagram). I have never been inside of this on an engine like yours, but on all of the engines I have ever worked on there is a one way breather valve (kind of like a PCV valve on a car engine), usually a reed or flapper covering a hole, that allows crankcase pressure out and allows a vacuum to be created in the crankcase. If this is valve is broken or stuck open the crankcase can't create a vacuum and the engine will use oil like crazy (the oil is pushed past the piston rings). This might be #5 in the parts list called an oil outlet valve (it looks like it could be a reed valve). #3 is a breather filter. #6 is a stopper plate. It is likely that one of these 3 things are causing your problem. If the breather filter is plugged-up it will do the same thing as a non-functioning valve.

 

[Brian123]

What's the exact definition of "eating oil" and "burning through oil like crazy"?

Same thought here, another question is what oil are you using? I have 3 small pieces of equipment that have Honda engines and I have never had any issues.

 

[dlundblad]

If it’s still smoking after the accident, no problem.

Sounds like you need to excessively keep it topped off though and it’s smoking? If so, that’s an issue.

Perhaps it was allowed to run low (although it should have a low oil shutoff switch) hence the excessive top off? Was it ran on uneven ground?

 

[Flankyou7]

Using 10w30 as specified by Honda for that engine. I too am surprised overfilling it is causing high crankcase pressure. Usually you just burn up the extra oil, new air filter, new plugs and you are on your way. Not this one! You can smell the oil burning in the exhaust and the rate we are burning oil, (no white smoke whatsoever) it's ovously not circulating and is actually buring up and being "pushed" out somewhere other then where it should be.

I agree with Wag123, it's a clogged breather, or any of those small parts inside the crankcase area is hopefully the problem. I am pulling the crank case cover today. I ordered the breather screen and liquid gasket, so hopefully that is what the problem is.

 

[Redmtnlawn]

Using 10w30 as specified by Honda for that engine. I too am surprised overfilling it is causing high crankcase pressure. Usually you just burn up the extra oil, new air filter, new plugs and you are on your way. Not this one! You can smell the oil burning in the exhaust and the rate we are burning oil, (no white smoke whatsoever) it's ovously not circulating and is actually buring up and being "pushed" out somewhere other then where it should be.

I agree with Wag123, it's a clogged breather, or any of those small parts inside the crankcase area is hopefully the problem. I am pulling the crank case cover today. I ordered the breather screen and liquid gasket, so hopefully that is what the problem is.

I’m having the same problem. After you installed the parts, did that correct the issue of the engine burning oil?

 

[Flankyou7]

Update: Replaced the breather screen #3 in diagram Wag123 posted (Pert #12367-Z6L-000 FILTER, BREATHER)

The little metal reed looking part (#5) wasn't broken or stuck open. Or it didn't seem like it was broken or stuck open. I cleaned it off and put it all back together with the new screen. Still was getting the same problem after doing so. Not sure if there is so much oil somewhere around that flapper and breather hole that the vaccum just can't be created. I don't know enough about engines to sort it out, but what Wag123 described is exactly what seems to be happening.

"The reed or flapper covering a hole, that allows crankcase pressure out and allows a vacuum to be created in the crankcase is broken or stuck open and the crankcase can't create a vacuum and the engine will use oil like crazy because the oil is pushed past the piston rings."

Could you drain the oil, run sea foam or the like through the oil system for like 10 -15 min. Drain it all out and refill with new oil to try and clean out the oil build up to try and get that vacuum to working again in the crankcase?

As for now, I Ended up replacing the engine to keep the piece of equipment in our work force. But I still have the engine and now have some time to possibly work on it.

Thanks for any more advice

 

[wag123]

Forget about the Seafoam idea. You have a mechanical problem.
The next thing that I would do is replace the valve stem seals and valve cover gaskets since they are an easy fix.
Since the engine is out of service it might not be a bad idea to reseal the entire engine. While I had it apart i would replace the rings. When a horizontal crankshaft engine is massively overfilled with oil, since oil doesn't compress, it can very easily blow-out a crankcase gasket. Like I said before, if the crankcase doesn't draw a vacuum it will burn oil like crazy. One would think that the engine would be leaking oil where a gasket has failed, but some of the gaskets are high enough up on a horizontal crankshaft engine that you may not be getting much (if any) oil leaking.