Harvard Fuel pump replacement -Wobble pump woes

[Chipfire]

Hi All

We replaced the fuel pump on a Harvard 2B and found the manual/wobble pump wont pressurise with the new Pesco
2P-R400BRD pump (tried 2) but the old Thompson TFD900-1 pressurises with one stroke of the wobble pump. So I reckion the wobble pump is fine its something about setup on the Pesco pump we cannot find.
Its been mentioined that TFD900-5 is the preferred pump.

Can anyone help ?

Thanks

[51fixer]

Hi All

We replaced the fuel pump on a Harvard 2B and found the manual/wobble pump wont pressurise with the new Pesco
2P-R400BRD pump (tried 2) but the old Thompson TFD900-1 pressurises with one stroke of the wobble pump. So I reckion the wobble pump is fine its something about setup on the Pesco pump we cannot find.
Its been mentioined that TFD900-5 is the preferred pump.

Can anyone help ?

Thanks

If you use a engine pump with a regulator, as opposed to the original with out, you plumb a single line from top of the wobble pump to the inlet and eliminate the loop.
Make sure you set up the inlet and outlet from the engine pump right as it can be reversed on the regulated pumps IIRC. Look close at drive rotation, the rotation arrows on the pump and the regulator orientation.

[Chipfire]

Interesting - that sounds logical to eliminate the loop.

What pumps yall using? anyone use the TFD900-5 ?

[Smaehr]

Rich,

What do you look for to determine if your fuel pump has a regulator or not. I have a similar issue in having to pump for a substantial period to get pressure. Just prior to buying my SNJ-5, the fuel pump was replaced.

Steve Maehr
N3261G

[51fixer]

2 types of pumps-
Oringinal F-10 Ceco CE9140. No adjustment can be made on the pump.
http://www.aeroaccessoriesinc.com/resou ... l_Pump.jpg
Requires the 2 line loop system

AN4101 series has the regulator attached to the pump housing. Several manufacturers of these. Come in various outputs, 200 gph, 400 gph.
http://www.aeroaccessoriesinc.com/resou ... Driven.jpg

Seriously, don't mess with these if you don't know about them.
Get the help of someone with experience.
T-6 fuel systems are fairly simple but a good number of people are dead due to fuel system issues.

If you can't get pressure quickly with your wobble pump- get it fixed. If your engine pump has a problem and you just took off that delay means you are hitting the ground before you can wobble the engine back to life enough to make it back to the runway.

If you need to learn about the insides of your T-6 join NATA.
Great articles. I suggest searching their archives for topics like the fuel pumps, and getting past issues with the info.
Contact WIX member Stoney- natrainer@aol.com
http://www.NorthAmericanTrainer.org

[Smaehr]

Rich,
Thanks for the reply and I promise not to mess with it. My wobble pump issue only occurs after an extended shutdown. After wobbling for 45 seconds to a minute, I get pressure. After that, I get immediate pressure for the rest of the day. The previous owner had replaced the fuel pump in an attempt to fix the problem. When that did not work, they rebuilt the wobble pump which also did not remove it. With your information, I will check out the pump and see what I have.

I have joined NATA and I have some really good advisors at the Dixie Wing CAF.

[Chipfire]

Thansk Rich and everyone else.

So does anyone have anything to confirm that the TF-900-5 (or AN4100 GOVT PT NO) is an approved fuel pump for the Harvard 2B?

[Smaehr]

Recommend calling Aero Accessories in San Antonio. They may be able to answer your question.
210-735-9467.

[51fixer]

From a WWII TO pertaining to Interchangeable Parts List-
http://www.aircorpsaviation.com/Website ... 3%2007.pdf

Page 30/31 of the PDF lists Interchangeable Engine Driven Fuel Pumps under items 29 through 39 for the T-6A-T-6D series.
Basically Type F-10 Type Pumps (200GPH) and F-11 Type are listed (400GPH).

This TO is from 44 IIRC