Author Topic: DZ 160 cdi: crankcase flooded with fuel?  (Read 236 times)

Online dimi

  • Clubman Class Poster
  • *
  • Posts: 15
DZ 160 cdi: crankcase flooded with fuel?
« on: 30, April 2018, 08:22:21 AM »
Good Morning, YS specialists,

As I was not able to fly for over one year due to other engangements, I finally was happy to start the season this year again.
I started the engine as usal, it was running at high idle, but very rich with a lot of smoke?!
By opening the throttle the engine quit running. I was able to start the engine again with same result. After some attemps, the enginge did not start again. I did not change anything, no setting change or something else.

At home I found the crankcase flooded with fuel?!

Any idea, how the fuel finds a way to the crankcase? In my understanding only air passes the crankcase.

Thanks in advance for your suggestions or help
Dimi
« Last Edit: 30, April 2018, 06:25:05 PM by dimi »

Offline Ashley Hoyland

  • Global Moderator
  • FAI Class Poster
  • *****
  • Posts: 2,063
  • Flying Class: FAI Pilot (P)
  • Other Status: Contest Director
Re: DZ 160 cdi: crankcase floated with fuel?
« Reply #1 on: 30, April 2018, 08:57:46 AM »
Good morning Demi.

I am pleased to hear you are getting back to F3A flying.

There should always be some oil in the crankcase produced from the blow back of fuel on the firing stroke to lubricate the 'bottom end' but not flooded as you have found.

With excess fuel in the crank case after it has stopped rich I think the first step is to replace the diaphragm in the pump which may have deteriorated whilst in storage and due to the poor flexibility of the diaphragm material giving the effect of the pump adjustment being richened

I hope this helps but if you have already replaced the diaphragm we will have to think again.

Kind regards

Ashley

Online dimi

  • Clubman Class Poster
  • *
  • Posts: 15
Re: DZ 160 cdi: crankcase floated with fuel?
« Reply #2 on: 30, April 2018, 12:06:54 PM »
Hello, Ashley,


I followed your suggestion but with no success. Same behavior.


I also opened the valve cover and even there I found fuel. I suppose it found a way through the pushrod cover of the exhaust valve to the head (engine is mounted upside down).


I also tried to turn the engine with open valve cover to see whether or not the pump on the inlet valve pushrod maybe leaks and the fuel goes from the head to the crankshaft, but this looks good.


Any other suggestions?

Online dimi

  • Clubman Class Poster
  • *
  • Posts: 15
Re: DZ 160 cdi: crankcase flooded with fuel?
« Reply #3 on: 01, May 2018, 09:50:19 AM »
Hi Friends,


Fault found!
The pump piston / housing has worn and fuel leaks to the camshaft compartment and then to the crankcase.
I ordered a new pump.


Regards
Dimi

Offline Ashley Hoyland

  • Global Moderator
  • FAI Class Poster
  • *****
  • Posts: 2,063
  • Flying Class: FAI Pilot (P)
  • Other Status: Contest Director
Re: DZ 160 cdi: crankcase flooded with fuel?
« Reply #4 on: 02, May 2018, 09:41:35 AM »

Hi Demi


Pleased you found the fault.  Another to add to our list for future reference.


Best wishes


Ashley