OS GGT15 petrol glow pump problems

[Doug L]

Hello,

 

I have had this engine for about six weeks now, its run in and done about 4 hours reliable flight time. It has suddenly developed a problem where there are air bubbles from the PD-08 pump to the carb, and the engine now doesn’t run correctly or reliably. There are only bubbles form the pump to carb, its clean from tank to pump. It was faultless to this point, and pressured nicely with no air bubbles. I also noticed fuel now in the pressure line from the crank? One can only assume the pump has developed a fault, split diaphragm or letting air in.

 

Is this a known problem with PD-08 pumps or a rare occasion?

 

Also, the issue has got me thinking, would a 2 stroke adjustable perry pump be more reliable option in the long run?

 

Cheers

 

Doug

[Engine Doctor]

Not familiar with this engine and pump but it does sound like a diaphragm or some part of the pump is leaking or failed. Can the pump not be changed under warranty? That would be my first option as knowing OS the parts will not be cheap. A perry pump may work but may not  supply the appropriate pressure ; plus you need to find where the air is entering the system. The fault may be a diaphragm but could also be the pump casing. 

Edited July 22, 2021 by Engine Doctor

[Nigel R]

Sounds like the diaphragm has failed and you now have crankcase pressure filling up the fuel line. 

 

Warranty repair i would hope, on this age motor. 

 

In general the os pump and regulator seem better built than the perry pumps and are essentially the same system. 

[Doug L]

Thank you for the replies. For info the pump was defective and replaced.

 

Cheers.

 

Doug.