Oil in the bilge!! AQ260 troubles...

[captmello]

Last time out the boat ran great. No problems at all. When I pulled out and went to pull the plug, only oil came out. less than a 1/4 cup, but it didn't make me happy.

I finally got around to tracking down the source and I found it.

The oil is flowing up through the dipstick tube at high RPM.

No performance issues, runs, starts, idles as good as ever.

Once stopped the oil level is back to normal on the stick.

Whats causing this? And please make it a cheap and easy fix.

Thanks.

 

[Don S]

Re: Oil in the bilge!! AQ260 troubles...

Pressurized crankcase pushes oil out the dipstick. Do a compression check both dry, then wet (oil in cylinders) to see if the compression comes up.

 

[Glastron_V210]

Re: Oil in the bilge!! AQ260 troubles...

Check out your conections from the valve covers to the spark arrestor. They should be open and free. Perhaps you have a clogged pcv valve if installed. These connections are supposed to vent any blowby pressure/oil fumes/partially burnt hydrocarbons to the spark arrestor. If there is a ton of blowby it will come up the dipstick too.

If you do have lots of blowby, the culprit is rings. Either really worn, or detonation damage creates blowby.

I'd do a comp. check to see if there is one cylinder which is a problem.



Chay

 

[captmello]

Re: Oil in the bilge!! AQ260 troubles...

Thanks for both replies.

I finally got around to working on the boat.

Don, I went to do the compression test but found myself outside, in the dark, working with a flashlight. My compression numbers came back seemingly fine. 145psi-155psi on all 8 cylinders. Unfortunatly, I did not test the cylinders wet as I was without proper supplies at the time.


Glastron_V210, I think you may be onto something. One thing i did in the spring was install breather filter hoses from the valve covers which are cheap aftermarket covers installed by the previous owner, to the flame arrester. One of the breathers was new and the other was a few years old. When I tried to blow through the older breather, it took some effort. the newer breather seemed much easier to blow though.

So, can I draw any conclusions at this point? Could I still have excessive blowby causing high crankcase pressure, even with what I would consider normal compression numbers? Do you guys think the clogged breather could be the culprit?

Thanks again.

 

[Gus E]

Re: Oil in the bilge!! AQ260 troubles...

Can your breather be plugged and the blowby you normally get and goes through the breather and back to the carb is now trapped and pressurizing the crankcase? Your compression check numbers seem good, so probably no cracked rings or pistons. Normal blowby can do strange things if confined.

 

[Don S]

Re: Oil in the bilge!! AQ260 troubles...

Usually, if you have really low compression with worn rings you can get blowby, or even a hole in a piston. But that would have shown up with your compression test. Your numbers look fine.
Are the crankcase vents open to the flame arrestor on both valve covers?

 

[captmello]

Re: Oil in the bilge!! AQ260 troubles...

Usually, if you have really low compression with worn rings you can get blowby, or even a hole in a piston. But that would have shown up with your compression test. Your numbers look fine.
Are the crankcase vents open to the flame arrestor on both valve covers?

The valve covers both have breather filters with hoses attached that run to the arrestor. The valve covers are a little different in that there are boxes inside the covers. So when you pull one of the breather filters out of its hole in the valve cover, you cannot see the rockers, etc, just the inside of the small compartment inside the valve cover. Could the aftermarket valve covers, combined with one clogged breather restrict the the release of the crankcase pressure?? Should I consider pulling the filter element out of the breathers to free up the air flow.

thanks again for the replies.

 

[Don S]

Re: Oil in the bilge!! AQ260 troubles...

Even the oem valve covers had boxes built in with breathers in them. Might want to pull them off and see if they are plugged up. Would sure be an easy fix.

 

[captmello]

Re: Oil in the bilge!! AQ260 troubles...

Well I finally got back to working on the boat. I pulled the valve covers and found them to be spotless on the inside. Nothing clogging the boxes in the covers at all. But the breathers still seem restrictive when I blow through them, even the newer one.

I'm going to see if I can just get some elbows to fit the valve covers and eliminate the breather filters and give it a try that way.

Unless someone else has a better idea...

 

[Bondo]

Re: Oil in the bilge!! AQ260 troubles...

I'm going to see if I can just get some elbows to fit the valve covers and eliminate the breather filters and give it a try that way.

Ayuh,.... As I read down yer thread, since post #4, I kept wantin' to say that,.... get Rid of the Filters,...