7.5EKD Generator Problem

redlightning

I have a Kohler 7.5EKD and have pressure in the motor crankcase while it’s running.  It will eventually blow out the dipstick and puke oil in the bilge.  It seems to run fine.  Powers the boat fine.  Can’t see to find any info on a crankcase vent or PVC system.  Any ideas?  Thanks in advance.

PickleRick

Give continental engines in Greenville SC a call.  While they are not currently a kohler marine dealer they used to be.  They lost the dealership to a Florida based company that quickly went under and they didn't seem interested in taking kohler marine back. They are in the business of industrial engines and generators. They are a dealer for kohler engines and generators, many of the same base engines are used in both applications.


Anyway, they have a tech guy that is very good with them, was with them when they did marine work.

Id offer to email you a copy of diagrams (I'm a kohler dealer and A+ certified tech) but they don't give me marine break downs in the kohler plus site.

Honda on the other hand, I'm a dealer and certified tech for their outdoor power equipment but I can access all their marine parts break downs on in.honda.

You're either going to find a crank case breather blocked or major blow bye in a cylinder.  Being over filled with fuel and/or oil can also cause this.   


Im not familiar with kohler marine engines but so far as I know they all still run HD (high detergent) oil?

On all current side shaft kohler models I work on breather on the v twins is in the valley between the cylinders.

On the new side shaft single cylinder it is much less complex and on the valve covers.

The new kohler diesels (not actually a kohler but rebadged from company they purchased) im not familiar with them although they use the motors in non marine applications that I probably can access parts break downs for if you get the engine model.

redlightning

Thanks for the feedback.  When I had the boat surveyed, I had oil analysis done on all of the engines and gearboxes.  Would blow by show up in this analysis as unusual levels of something?
I did find a parts break out last night showing a reed, filter and hose that ties back into the breather where you mentioned between the cylinders.  Would the motor run good under full load with a blow by problem?  It’s not overfilled with oil.  No fuel odor or indication of fuel issue.  Again it runs fine.

aero3113

Could the wrong dipstick be installed? The oil level might be too high and when the oil heats it vents out?

Liberty44140

If this is a diesel, I highly recommend joining boat diesel.com. Not as active as this site but definitely well worth $25 a year and lots of good feedback on that site. They have a section specifically for kohler diesel generator discussion.

redlightning

aero3113 said:

Could the wrong dipstick be installed? The oil level might be too high and when the oil heats it vents out?

I guess it’s possible.  I don’t think that’s the issue.  In looking at parts break out seems correct.  I have had 2 incidents.  First time running gen after taking delivery. Ran it 3-4 hours and shut down.  When I checked error code low oil pressure.  That’s when I found oil in the catch pan and everywhere.  I thought the dip stick might not have been seated properly.  Cleaned it up added oil and she fired right back up.  Ran of for an hour or so on next outing and again dip stick loose and oil puked out, motor shut down.  

Yesterday I decided to run it in my slip and watch it.  Started it so motor was cold.  Oil level at mid point of low/full indicator.  Right after I started it I pulled dip stick because I had read something about crankcase pressure.  Really surprised how much pressure I got hit with.  Mist of oil hit me.  Not that I know what it should be but worked on my cars when I was a kid and I’m thinking this is not right.  If this is cylinder head pressure i would think the motor would run rough or provide some other clue.  

redlightning

Liberty44140 said:

If this is a diesel, I highly recommend joining boat diesel.com. Not as active as this site but definitely well worth $25 a year and lots of good feedback on that site. They have a section specifically for kohler diesel generator discussion.

Thanks for input.  This is a gas generator.

PickleRick

Your oil is a high detergent oil, it will froth when running which is what it's supposed to do.  How much, I'm not certain as I'd have to compare blow by of a healthy engine to that of yours.  

Kohler felt crank case vent issues were common enough 20 years ago to require a gauge for testing the crank case pressure to be purchased from them to be a dealer.  I've never used it.  

If you can access both plug holes a compression tests comparing both cylinders wouldnt be a bad idea.  A simple blown head gasket between cylinder and push rod valley will pressurize the crankcase without too much loss of power.  If one cylinder is 145 and the other is 85 you know where the issue likely is.  

The breather isn't accessed easily on a horizontal v twin zero turn, im sure it's even less accessible on a boat.  

redlightning

I was wondering if compression test might be a good step in troublshooting.  Breather parts don’t look easy to access for sure.  I think it would require removing a coolant hose.

redlightning

https://youtu.be/7rSNXu99i14

So compression check shows around 150psi on each cylinder.  Replaced the crankcase breather reed and filter.  i just have no frame of reference if what you see in this video is ok.  maybe the o-ring that seats my dipstick is worn and allowing the pressure to push it out?  if anyone has a 7.5ekd and could see what they experience when removing the dipstick with it running it sure would be helpful. Thanks!