Red particles in float bowl, cause unknown. - Page 3

rgmwa · #21 12-23-2015, 03:49 PM

Sink,
The debris we found was more than just a few particles. I don't want to replace the pump if it's not necessary, so we might try some more ground running first and check the bowls again. My plugs were pretty black too suggesting the engine is running too rich. Any possible link between that and a failing diaphragm?

Bevan · #22 12-23-2015, 04:09 PM

Are the fuel caps painted red by any chance? If so, it could be paint chips from the caps.

Just a thought.

Bevan

rgmwa · #23 12-23-2015, 04:12 PM

Bevan,
No - standard cap and the gascolator is clean.

crashley · #24 12-23-2015, 10:11 PM

Hi two plugs will be really black and the other two will be black especially after extended ground runs The engine will run very rich on two cylinders at idle or ground runs but will lean out when actually flying

The red particles must be from the inside the hoses or from the diaphragm as they are only appearing after the gasculator screen

rgmwa · #25 01-09-2016, 07:51 AM

We replaced the fuel pump today and opened up the old one. The diaphragm, which comprises three leaves of thin red rubber, seemed fine. However, there was some corrosion deposit on the inside of the pump housing and also on the plate in the centre of the diaphragm. The corrosion surprised me as the engine only has about 30 hours on it, all using 98 RON unleaded mogas.

However, we found nothing to explain the rubber particles in both carb bowls that I reported previously. I can only surmise that these were shed from the faulty pressure side fuel hose that was replaced by Van's A&P before the engine was shipped (ASB-912-061R1). In hindsight, I should have checked the bowls soon after first engine start instead of at the end of my 25 hour Phase 1. Lesson learned! Since initially cleaning the bowls, the engine has run for about an hour, and a second check today found the bowls were clean.

Jetguy · #26 01-09-2016, 11:13 AM

Robert, thanks for a great follow up on this problem. Maybe you could send those photos to your Rotax Field rep for Australia.

rvbuilder2002 · #27 01-09-2016, 12:18 PM

Quote:

Originally Posted by rgmwa

I can only surmise that these were shed from the faulty pressure side fuel hose that was replaced by Van's A&P before the engine was shipped (ASB-912-061R1). In hindsight, I should have checked the bowls soon after first engine start instead of at the end of my 25 hour Phase 1. Lesson learned!

I don't think any of the material in any of the hoses is red.

I am pretty sure that checking/cleaning the float bowls is one of the check list items in the PAP, to be done after flushing fuel through the fuel system, but before first flight.... but I could be wrong.

Mich48041 · #28 01-09-2016, 02:15 PM

Quote from PAP page G6-1 before first flight:

Quote:

Remove any remaining fuel by removing gascolator bowl and running electric fuel pump until no more fuel comes out. Note presence of any debris in gascolator bowl and clean screen then re-install gascolator bowl and safety.

Remove carburetor bowls and check for debris.

rgmwa · #29 01-09-2016, 03:51 PM

John: I'll send the pump back to our Australian Rotax distributor. If I'm lucky, they might refund me the cost of the new one. I don't think the corrosion deposits would necessarily have caused a problem, but I'm happier knowing that pump is no longer on the engine.

Joe and Scott: I checked the gascolator as per the PAP and again at the 25 hr mark and it was clean as a whistle. However, I missed the initial carb bowl check in the PAP - my mistake. I agree the fuel hoses all appear to be black, so I really don't know where the reddish particles came from. Anyway, they're not there any more, and I'll be keeping a close eye on the bowls from now on.

Sink · #30 01-10-2016, 07:58 PM

The corrosion in the picture is from water in the fuel. The new pumps are aluminum and water shows up this way. The old pumps were steel and water didn't affect them the same way. Slight corrosion isn't an issue. Heavy corrosion is. One thing about ethanol fuel is water is absorbed and runs right through the engine and you would never know it. It also helps with this corrosion issue as the water is held in solution.

Hi rgmwa,

Did you find red fuel pump diaphragm particles missing from the diaphragm?
If it was smooth everywhere and the edges were all intact this may not have been the red particles in the carb bowl? Just a thought to keep your eyes open for a while. Small enough particles will go right through the carb main jet. That said even the smallest particles can get in the idle jet and make idling rough and the carbs won't sync correctly.