Frustrated & Confused

My engine (Lyc IO-360-M1B) and prop (MT 2 blade CS) have finally arrived and I've spent the last few days going over the Lycoming Operator's Manual and Overhaul Manual, and I have to say that I'm surprised by the LACK of detailed information about the engine. But I'm really confused about the Fuel Injector servo. It's an AP RSA-5AD1 and the Lycoming manual has 1 drawing that shows some of the ports.



The thing is, the servo comes with two fittings already attached. At first I assumed they were the input and output ports.



But after looking at the figure provided by Lycoming, it shows two other ports as input and output. So, what are these ports for and why do they have fittings already attached? They aren't discribed in the manual. If fact the one on the back isn't even shown.



I looked at the AP web site for a detailed drawing of the servo, but no dice. Does anyone know what these ports are, or can you point me to someplace that might have more detailed information?

Bill Rambo
RV-7A

Red plastic cap in your photo #1 (the middle photo) is the fuel in. Remove this at each annual. There is a screen inside to clean. Before you take it off remember to get new O rings (2) different sizes required. Do not reuse them if possible. Call AFP and ask nice for an instructional CD ROM.... they will send it free.

Photo #2 (the last photo) is the fuel out to the spider.

Do not cut any of those safety wires or remove any of the safety wired plugs.

OK, why does the Lycoming manual say differant?

I am assuming AP for Airflow Performance servo? If not excuse my interference on the post. If it is Airflow I can tell you my threads were damaged on the fuel inlet from the pump, the other goes to the fuel distro spider on the top of the engine. I asked them to send the new fitting, but they said no, the new fitting needs to be installed and the flow calibrated and confirmed. When I got it back I had new test paperwork with the servo for the new fitting. Take this with a grain of salt but I have found most of the Lycomng manuals and information pretty dated...like it was printed in the 50's..and maybe it was. But fuel injection stuff is pretty new technology compared to information on the engine itself.

Use any of outlet.

I am using the outlet that shows up in the lycoming manual as an outlet (shown photo number 3 (your first posted link) and photo number 1 (second link)) There are two outlets on opposite faces to allow for a vertical installation like I have or horizonatal like in some of the production airplanes (cherokee 180s is one). Use which ever one works best.

I too was confused and called Percision Aeromotive to get a manual. They sent me one (for $20) but it was a trouble shooting manual. Then called again and they sent me maintance training manual for another $20. Called again and finally got a parts manual but it is not too helpful as there are so many variations of the servo that there are 10 pages of parts for each part. Here is a link as now it looks like they have them all on line for free.

http://www.precisionairmotive.com/servpubs.htm#MAN

Talked to Percision at OSH and they gave me the straight skinny on which ports to use.

It seem you engine vendor chose a fuel injection servo with the fuel outlet on the BACK of the unit rather than on the FRONT as in the Lycoming documentation and that is usually provided. Should work fine however. You can see the INLET port is clearly marked on the left side and what I think is OUTLET on the left rear where the 90 degree fitting is.


Front View


Rear View


Document

Thanks for the replies. The figure shows the top port as being available for the fuel pressure sender, is this where others have connected it? I saw Dan C. put a "T" right off the fuel pump and that was what I was going to do, but if this will work also, it might be a better option.

Bill Rambo
RV-7A

Brambo said:

Thanks for the replies. The figure shows the top port as being available for the fuel pressure sender, is this where others have connected it? I saw Dan C. put a "T" right off the fuel pump and that was what I was going to do, but if this will work also, it might be a better option.

Bill Rambo
RV-7A

Click to expand...

I have my pressure transducer on the firewall feed off the top port listed in the figure for fuel pressure. Others have just downstream of the fuel pump and there is also a port up on the spider up top you can use. I did not want another fitting in the fuel line before the servo and did not want the pressure line to run on top of the engine and another hole through the baffling. I have had no problem with the pressure off the servo.

Brambo said:

Thanks for the replies. The figure shows the top port as being available for the fuel pressure sender, is this where others have connected it? I saw Dan C. put a "T" right off the fuel pump and that was what I was going to do, but if this will work also, it might be a better option.

Bill Rambo
RV-7A

Click to expand...

Note that most EIS manufacturers recommend against putting the mechanical pressure transducer ON the engine due to vibration. That is why the transducer is usually mounted on the firewall via a flexible cable to isolate the pressure transducer.

Frustrating post. Too bad.

Holy Necro-post Batman!

DTARM1 said:

Frustrating post. Too bad.

Click to expand...

Welcome to VAF! You might find many posts frustrating, but people are nice. Many very knowledgable members here and have the relevant information. A bit of sifting is always needed to agree on the obvious. Once it becomes obvious to all, that is.

With your background you should feel free to join in, but as in all large groups were credentials are unknown, you might get challenged by a neophyte. It's OK, just become a teacher and state your case. Many try to use facts and data when possible, and experience when that applies.

Again - welcome, and tell us about your interests and what you might be building or repairing.