Universal M 25 Crankcase Breather/Vent Hose

[Dick Spangler]

I really don't like the current arrangement of the crankcase breather hose which vents oily fumes directly into the atmosphere of the interior of the boat. A couple of questions:

1. Has anyone re-routed the crankcase breather hose of their Universal MD25 to the air intake/manifold?
2. Does anyone have any experience with Racor crankcase filters?

Thanks

[Phil Shedd]

Dick

My M25 had a hose that runs from the valve cover to the top of the intake breather . This take care of the oil fumes



The top of the breather has a fitting to take the hose. Looks like it was added later. The photo does not show the fitting very well.

Phil ( in Seattle WS)

[Maine Sail]

These work well and can be direct plumbed right into the air filter with a hose barb..

http://www.jegs.com/i/JEGS/555/52205/10002/-1

[Steve Laume]

My vent hose ends right in front of the air intake. I believe the idea was that the engine would draw any oily fumes back into the air cleaner.

Whenever I check the foam filter in my air cleaner it appears to be working as planned. This is most certainly an original set up as there is a cute little stainless clip on the air intake that the hose is held by. It could just as easily be done with a wire tie.

A fitting bolted into the air intake with a hose barb would be more positive, Steve.

[Maine Sail]

My vent hose ends right in front of the air intake. I believe the idea was that the engine would draw any oily fumes back into the air cleaner.

Whenever I check the foam filter in my air cleaner it appears to be working as planned. This is most certainly an original set up as there is a cute little stainless clip on the air intake that the hose is held by. It could just as easily be done with a wire tie.

A fitting bolted into the air intake with a hose barb would be more positive, Steve.

Just be sure you have a way to separate any oil out of the line. It can and could potentially cause a run-away diesel. The foam serves this purpose.

When I built mine I used a 3" brass nipple and some rolled up oil absorbing pads stuffed inside to catch any residual oil but allow vapor and pressure to pass.

I found a K&N filter at a motorcycle shop with the same diameter as the intake throat on the M-25. Sorry I can't remember the part number. The arrow is pointing the the 90 degree brass fitting I inserted for the PCV valve I made.


Here's a picture of the PCV set up I made. The hose runs from the valve cover to a brass nipple with barbed fittings. Inside the brass nipple I rolled up some oil absorbing pad, loosely so as not to restrict flow, to absorb any stray oil escaping the valve cover so it would not pass to the intake. I would change this rolled up pad at each oil change. By adding this PCV valve I no longer had any oil smell in my engine compartment after running the engine.

The factory set up just vents the crank case into the engine compartment near the filter and does not always do a good job at removing the "oil smell". If you add a K&N make sure you have enough room in the underside of the filter for the 90 degree fitting for a PCV. My K&N was off set slightly giving me room to drill through the bottom and insert a fitting. I purchased all the brass fittings at Home Depot and did the whole project for under $50.00 including the K&N filter.

[Dick Spangler]

Thanks for the all the great input. I found this link that may be of interest: http://www.y8s.com/celica_gone/air-oil/.