Oil / Fuel In Manifold Pressure Guage

Re: Oil / Fuel In Manifold Pressure Guage

by Chris Adams » 13 years ago

Chris Adams

1 5 0

Mike we are running 912's not 914's. Tony the balance tube should remain between the manifolds....it is for minor equalization of the 2 sides once balanced (see video on carb sync.). A pipe is added to the left of the tube for manifold pressure readings....but is only used for variable pitch prop.applications. Rob at Rotec research has sugessted a restrictor / oriface in the line to block the oil....but could not explain its presence....nor have I ever seen this ? Still stumped as the engine runs great...lots of power...motostat and compression checks good.

Re: Oil / Fuel In Manifold Pressure Guage

by Roger Lee » 13 years ago

Roger Lee

131 5.38k 5.44k

Hi Tony,

Food for thought and just a guess. Some bourdon tubes have fluid in the tubes. It makes them less susceptible to outside changes. The oil may have leaked out. If you remove that gauge and clean out the MAP tubing and put in a new gauge and there is no more oil then you have your answer. I would lean a little this way too since it is a small limited amount and an odd color.

---

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

Re: Oil / Fuel In Manifold Pressure Guage

by MARK JACKSON » 13 years ago

MARK JACKSON

12 332 11

Could the oily liquid be some type of waxy coating from inside the pipe bore that either heat or fuel vapour has thinned and caused it to liquify and run into the instrument.

Just a long shot.

Mark

EDIT

Ive just read your post Roger, I think we posted at the same time, I think we are thinking on similar lines.

Re: Oil / Fuel In Manifold Pressure Guage

by Mike Goodrich » 13 years ago

Mike Goodrich

8 123 0

I really don't know how I read 914 instead of 912, I'll have to get new glasses.
On the same lines as above, could the continuous vacuum (plus heat mentioned above) be pulling oil or wax out of the tube inner diameter?
Mike G

Re: Oil / Fuel In Manifold Pressure Guage

by Tony Garrett » 13 years ago

Tony Garrett

20 37 11

Roger
I agree with you. I think the oil is from the bourdon tube.
Tony