Not much to it really. Popped it apart, cleaned it up, used some aviation
Permatex to seal that gasket and bolted it back together. Now to replace
the fuel line from the pump to the carb.................kinds fell apart.
Len and Pat Novak
1978 GMC Kingsley
The Beast II with dash lights that work and labels you can see!
Fallbrook, CA new email: B52Rule
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375
www.bdub.net/novak/
-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Ken
Burton via Gmclist
Sent: Sunday, March 22, 2020 12:40 AM
To: gmclist
Cc: Ken Burton
Subject: Re: [GMCnet] onan fuel pump
That same Bendix / Facet / Purolator / NAPA pump is used on low wing
carburetor airplanes as a boost pump. The only difference is the bottom
piece
that holds the filter in place has a tab on it for safety wire. The other
difference is because it says FAA on it, they cost 3 times the price.
We never replace the pumps. We always take them apart, clean an polish them
if necessary, and reinstall them with a new gasket and filter. The
gasket and filter is available from NAPA. It use to cost around $10.00 and
have a NAPA number because NAPA sells or sold the pumps under their
Balkamp name. I have one of those kits hanging on a peg at the airport.
Unfortunately I am not there to find the number. They are very common
around airports that work on Continental or Lycoming powered aircraft
engines. Those bottom gaskets do wear out or harden and usually need to be
replaced after 20 to 30 years of use. I have never seen a pump so broken
that it needed to be replaced.
There is nothing much inside on except a check ball, a slide, and some
springs. Open it up by turning the big nut on the bottom, clean it up
(especially the check ball), and replace the filter and the gasket.
I tried to find the filter and gasket on NAPA's web site and failed. The
NAPA part numbers for the complete pump is NAP87SV or BK6101074. At my
local NAPA, which I seldom visit, the kit is on a card hanging on a peg in
the store.
That pump has been around for 60 years. It has been used on everything from
John Deers, to Onans, to 1970s GMC Jimmys, to my Grumman. Replacement
prices for the entire pump are also all over the place starting at around
$85 to over $250 for airplane versions.
The in line fuel solenoid also is important and can get clogged. They can
be cleaned with carb cleaner. A lot of people have removed them and two
things can happen. If you have your Onan fuel line teed into the fuel line
for the main engine like they did on the Royale and other non-GM upfitted
coaches and if the onan carb needle and seat sticks open or the bowl is dry,
the main engine pump will suck air through the Onan carb. The engine
will die from fuel starvation. It will run off of the aux tank.
The second thing that can happen on all coaches is if needle and seat leaks
at all, the gas in the line will return to the tank. The Onan will then
be hard to start because the pump has to pull all of the air out of the line
again before it can supply gas to the Onan. I suspect that is why many
people install a prime switch on the Onan to get around that problem.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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