[MRCG] PU-181 Generator Fuel/Lube

[Tim]

Hi Guys - well I figured this topic would have generated some discussion.
As usual, there is a lot of expertise out there!  Thanks for all the
inputs. Many good ideas and references surfaced....

But it looks like the Signal Corps didn't issue any known clarification on
this apparent 2:1 discrepancy of fuel-oil mix ratio (Tech Manual versus
generator data plate).  By way of comparison, the 1945 Manual - (TM11-971)
for the PE-162-B generator (same engine) advises a 16:1 mix ratio - but
that generator has a half-gallon tank.  Maybe the tech writer who wrote the
PU-181 manual in 1951 was not paying attention since the PU-181 has a one
gallon fuel tank.  So putting the same 2 "cap measures" of oil into the
PU-181 otherwise yields a 32:1 ratio in that one gallon tank.  Betcha - Who
knows...Yet another academic mystery...

Anyway, I have been using modern 2-stroke engine lube oil and (recently)
unleaded 87 Octane gas in my generator at 32:1 and is has worked fine for
many decades.  Thirty years ago I was using SAE 30 at 16:1 in it before
modern lube became available.  (And at 16:1 I didn't need to put a
tablespoon of Citronella Oil in it to repel mosquito's too - LOL)

It smokes a little, has great compression, starts very easily and it still
has the original plug.  I have not mic'd the bearings or examined the wear
surfaces but so far, so good.  I have put several hundred hours on it and
it was an old veteran when I got it.  A nice little vintage generator for
my vintage radio field ops..
Thanks All!
Tim
N6CC


On Mon, Apr 14, 2014 at 12:38 PM, Tim <timsamm at gmail.com> wrote:

> OK Wise Guys - here's a question for you regarding engine oil and
> concentration.
>
> The PU-181/PGC-1 is a 2-stroke gas generator rated at 300W, 240/120 VAC.
> It uses a Jacobsen GE-12F engine.  The generator is designed for the PGC-1
> TTY terminal but also for general purpose use.  It has a completely
> shielded ignition system - it is radio friendly. This same engine is also
> used to power the GRC-9 DC generator adaptation.
>
> The placard on the fuel tank advises a *16:1 fuel-oil ratio*.  It states
> to use SAE 10 weight below 32 degrees F and SAE 30 for operation above 32
> degrees F.
>
> However, the Tech Manual TM11-943 "Engine Generator PU-181/PGC-1" (US Army
> 1951) states to use a *32:1 fuel-oil ratio* and it says to use SAE 10
> lube oil, it says nothing about SAE 30 or temperature.
>
> So regarding mix ratio, which is it?  I don't know if there were any
> post-1951 tech advisories that addresses this apparent discrepancy.
>
> Comments?  Thanks
> Tim
> N6CC
>