Excessive oil coming from my breather hoses.

[kimo82265]

I have a 570a carb motor with excessive oil coming from both breather hoses out of the valve covers. What would cause it, and what can i do the fix it????? I replaced the stock flame arrestor with a coast guard approved k & n filter. Oil is dripping out of the filter and ending up on top of the intake manifold. Any help would be great. Thank you jim.

 

[Bondo]

Re: Excessive oil coming from my breather hoses.

What would cause it, and what can i do the fix it?????

Ayuh,... I'd think a Compression, 'n Leak-down tests would be a good pace to start...

 

[kimo82265]

Re: Excessive oil coming from my breather hoses.

Bond-o, what should I be looking for. If the compression leaks down what is that telling me. Will perform a compression test my next day off. Are you thinking bad rings and or bad valve guides. Boat runs within normal temp, although seems like the last time I took out, I could not get it up to full throttle. Thank you for the help. Jim

 

[Don S]

Re: Excessive oil coming from my breather hoses.

Do the compression test and following tests in the spec below. It's a Mercruiser service bulletin, but Volvo had one just like it, only I don't have a copy of the Volvo version. It came from GM.

View attachment 97-25 Compression Test.pdf

 

[kimo82265]

Re: Excessive oil coming from my breather hoses.

Don, will do them and post what I find. Thank you.....Jim B

 

[sschefer]

Re: Excessive oil coming from my breather hoses.

When valve guides are in question I look for a puff of smoke after a cold start. If I don't see that and compression is acceptable I throw a vaccum gauge on it. If the needle's jumpy it's an indication that the valve guides are worn or a valve is leaking.

However, I'd be remiss in my duties if I didn't mention that the #1 cause of blow by on boat engines is over filling the crankcase after an oil change. You think you got it all pumped out but you don't and then your put as much in it as it calls for in the manual and now your a 1/2 quart or more over. Half the time you don't know whether to trust the dip stick or not. When its on the trailer the oil's in the front of the pan and when its in the water the oils in the back of the pan.

 

[kimo82265]

Re: Excessive oil coming from my breather hoses.

Steve, thanks for the info. I'm lucky in that I can use my drain plug and catch the oil in a pan. I guess this still does not mean that I'm draining all the oil. The oil that is blowing out of the vent lines and onto the flame arrestor looks very clean like it came out of new bottle of oil. I will perform the test in the morning and post what I find. I also notice that my oil level drops each time that I check it prior to using it.

 

[kimo82265]

Re: Excessive oil coming from my breather hoses.

Don did my compression test today and this is what I found. #1=140, #3=135, #5=140, #7=135. All spark plugs on that side looked good, no extra oil on them and burning clean. #2=135, #4=80 and 80 with a wet test. #4 spark plug was missing it's electrode tip/ insulator. #6=150, #8=135. The other funny thing was #2,#4 spark plugs were lose when I went to remove them. Now what. Should I buy new spark plugs and run it and see if the compression comes up? or should I go right to the leak down test for #4. If so how many turn past #1 TDC would it be for a chevy V8. Could I also feel when #4 is at tdc by sticking my finger over the spark plug hole??? From the wet test not changing the compression reading, is it more likely than not some sort of valve damage????. Will wait to see what you say before I pull the head off. P.S what would of caused that spark plug to have broken apart like that???/Thanks in advance for the help. Jim B.

 

[Don S]

Re: Excessive oil coming from my breather hoses.

Did you just buy this boat?

If you bought it like this, my guess is the seller removed the plug so it didn't backfire out of the carb. Probably due to a bad intake valve on #4. You can put new plugs in and run it if you want, or do leakdown tests if you want, but since the compression didn't change with oil in the cylinders, you have problems with the head. Personally, I would pull the head and have a look.

 

[kimo82265]

Re: Excessive oil coming from my breather hoses.

Don, thanks,,,is the damage done, or will I cause more if I run it like this???????Back to my original question about the oil out of the breather hoses, would that bad #4 valve or valves cause that ?????. Thanks for the help. Jim B

 

[sschefer]

Re: Excessive oil coming from my breather hoses.

Don, thanks,,,is the damage done, or will I cause more if I run it like this???????Back to my original question about the oil out of the breather hoses, would that bad #4 valve or valves cause that ?????. Thanks for the help. Jim B

Jim, it sounds like a valve to me also. Could just be a broken spring. The keepers might have let loose and you may have a hole in the piston or the guide is badly worn. That spark plug conditon is one of extreme lean out from the all the air that cylinder is getting. Running it will only make the repair cost go up.

 

[kimo82265]

Re: Excessive oil coming from my breather hoses.

Steve, thanks for the info, started pulling it apart today. Hope to have the head off in the morning. I will post what I find. Thanks again to all that helped me out. Jim B....

 

[Bondo]

Re: Excessive oil coming from my breather hoses.

Steve, thanks for the info, started pulling it apart today. Hope to have the head off in the morning. I will post what I find. Thanks again to all that helped me out. Jim B....

Ayuh,... Post some pictures when ya get it torn down...

Hopefully, it's just a burnt valve... 'n not detonation damage...

 

[kimo82265]

Re: Excessive oil coming from my breather hoses.

Took head down to the shop today and found this out. #4 intake valve was not sealing( only 15%) Found a small fracture to the valve face. 70.00 dollars later, and two valves later and I'm back in business. Ordered my new gaskets and will put her back together next week. will try and post some pics. Jim B

 

[sschefer]

Re: Excessive oil coming from my breather hoses.

That's great news Jim.

 

[scoflaw]

Re: Excessive oil coming from my breather hoses.

Don't want to be a buzzkill here, but what does 2 bad valves have to do with your original oil problem. Maybe you should do a leak down test on the other side of your motor, to see what kind of shape your rings are in.