oh turds! compressor motor starting cap's 'blown out' but it's a"non-standard"

[dave]

my ancient 4hp sears craftsman air compressor needs a starting
capacitor, I've determined (through a process of elimination). I still
have the original owners manual, and the capacitor is "part of the
motor", not shown in the parts blowup, or parts list, as a seperate
orderable part. further, the friggin' thing seems to be a 'non-standard'
mfd rating, too (it doesn't 'fall into' any capacitor size-groups of any
maker's starting cap's I can find online. matter of fact, it's not even
close):

the one in it now is
110 volt, 485-580 mfd
mallory #139852-49
seems a slightly non-standard SIZE as well:
diameter: 1 13/16ths inch, and
length, overall, excluding 'spades': hair over 4 5/16ths (but clearly
under 4 3/8ths)

atttempts to locate same by the mallory part number on it entirely
unsuccessful. so (physical size and 'look' issues aside) can I "daisy
chain" two cap's and achieve the same net effect, somehow? appearance
"not an issue", I just need a working compressor. I know I can replace
the cap with a higher voltage cap, and that'd be fine (maybe even
desireble) but what about the mfd rating? if I must, is it best to go
'bigger mfd numbers' or lesser?

thanks for tips on this, guys

 

[Bill Noble]

That is a common value, either of these two will work at about $8 each

http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=3363840&PMT4NO=72152023

http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=3363841&PMT4NO=72152023

 

[Franc Zabkar]

http://www.instruction.greenriver.edu/avery/activities/tech/images/Shift_Key.jpg

- Franc Zabkar

 

[David Nebenzahl]

One trick we used to do in a emergency is to get two DC electrolytic
capacitors of twice the needed AC capacity and connect them in series,
either both + leads or both - leads together and wire the remaining
leads to the motor to replace a single AC capacitor. Gets you going
while you look for the correct replacement.

That can't be safe, can it--running AC through two polarized capacitors?

(Hey: two explosions for the price of one!)