Oil / Fuel In Manifold Pressure Guage

Re: Oil / Fuel In Manifold Pressure Guage

by Tony Garrett » 14 years ago

Tony Garrett

20 37 11

p reino
I have removed some of the liquid from the MP gauge. It is oil and it does not mix with water.

Tony

Re: Oil / Fuel In Manifold Pressure Guage

by Chris Adams » 14 years ago

Chris Adams

1 5 0

Hi Tony, What is your installation ? Time on engine ? Has this been an ongoing problem or did it just appear ? I also see you have 2 gauges....are both filled ?

Re: Oil / Fuel In Manifold Pressure Guage

by Tony Garrett » 14 years ago

Tony Garrett

20 37 11

p reino
The engine was new when I installed the gauges. Both gauges got oil in them in the first few hours. I now have 300 hours on the engine and gauges. There was no change in the amount of oil after the first few hours.
Tony

Re: Oil / Fuel In Manifold Pressure Guage

by Mike Goodrich » 14 years ago

Mike Goodrich

8 123 0

I thought we were talking about the boost pressure in the inlet manifold (Rotax call it the "airbox") of the 914 so my earlier assumptions are off base.

P Reino, I'm interested to see that on a 914 you are measuring the manifold pressure (MAP) at the balance line. Just to make sure I've understood you, the balance line in question is the one that is downstream of the carburators (between the carbs and the cylinder head) right? From what I've understood all the manifold pressure data given in the manuals is airbox pressure not balance line pressure. Have I misunderstood something that you are doing?

Tony
What I understand from your posts is that you have installed a sort of permanant carb balance set up with vacuum gauges between each carb and its cylinders and with the balance line disconnected. I would have thought that it wasn't a good idea to disconnect the balance line because it does help equalise the carbs if they are slightly different. I'm interested to know why your set up was done like this and what the advantages are.

I hope Roger will step in here because if these set ups are correct I'm about to do something wrong.
Mike G

Re: Oil / Fuel In Manifold Pressure Guage

by Mike Goodrich » 14 years ago

Mike Goodrich

8 123 0

Sorry guys, I just realised that I misinterpreted the manual and probably confused some of you at the same time.
Reading the manual yet again I realise that Rotax talk about "boost pressure" in the airbox and "manifold pressure" downstream of the carbs, although they don't seem to say so clearly.

This has been a very useful thread for me because I am in the process of fitting a MAP gauge and a fuel/airbox diffrential pressure gauge. I had, wrongly, assumed that they would both be connected to the airbox and I now realise my mistake.
This doesn't help you guys with your problem but it shows the value of this forum, thanks Roger.

I'm still interested to understand what causes your problem because I shall be using the UMA electronic pressure sensors and the air connections on them don't like liquid.
Mike G