Fuel Pump Drain Hose Size?

Sean, I recall your catch can...  Thanks for your comments.

Mike

Sean, do you have a photo of your catch can?

Hi Sean,

I have a detailed article entitled "Rotax 912 Fuel Pumps" from Rotax-Owner.com dated 9/15/22.  It discusses the "catch can".  It says "Oil coming out of this line indicates a Garlock seal failure.  Fuel coming out of this line indicates a fuel diaphragm failure."  So, the question is "how much oil or fuel in the catch can indicates a problem?"

Mike

Hi Michael,

"how much oil or fuel in the catch can indicates a problem?"

Good question.  Short answer, I don't know.

In my case I have an estimated 3-5 ml/175 hrs of oil in my fuel pump drain catch can & no fuel. I consider this to be acceptable (no problem). The amount of oil does not seem to be increasing.

The smear of oil in the bottom of the can (bottle) could be assembly oil (this is a new 912) or the very small weep that many seals have, that is not considered to be significant.

I would be alarmed if there was any fuel at all and concerned but not alarmed if the oil emissions showed a significant increase (say 20ml/50 hrs)

😈

Hi all

The Corona pump was developed (introduced in 2010) for Rotax and had a design to solve issues with previous stamped metal bodied version.  The old versions had vents into the area between the pump diaphragm and the oil seal on the pump shaft.  This always would, over time, leave oil residue on the engine side as a oil film and created the desire to solve this.  The solution was to provide a port that connected to a drain hose to move accumulated oil residue weep away from the engine for a cleaner engine and reduce any flammable surface coating.  

The oil you see in a vent line is very normal.  it should not really weep to the point of a measurable amount, the volume is extremely small.  If you have enough to drip from the end of the line it suggests extremely high crankcase pressure that is overcoming the oil seal of the pump shaft.  Fuel pumps should last to TBO and are then a 100 % replacement at that point. 

Cheers