Hi all,
I am a software guy, and these are my first ever small engines... (i.e. I don't even know what I don't know about small engines)
For redundant redundancy I decided to get two HF Predator generators, so I'll have a hot spare, or if I might need more power.
By chance I ended up getting item# 63960 and item# 63961 (the CARB versions of the 4375)
they look cosmetically different, and they are obviously from a different supplier
from minor stuff such as the 61 gas tank filler is offset to one side, while the 60 has it centered
the tubular frame has the cross members at a different locations on top
the cover of the pull cord on the 61 is red, while the 60 is black.
to some stuff which might indicate better quality:
the 61 valve cover is cast while the 60 is stamped metal
the 61 air filter box is stamped metal, while the 60 is plastic
the casting of the engine body seems better on the 61, sharper corners, vs more rounded off/sloppy casting. (also the etching of the serial number etc seems better/sharper on the 61)
the carburetor also seems better manufactured on the 61
they both started on the first pull (actually not even a full pull)
the 61 kept running at closed choke, though sounded bit "sickly", so I switched the choke to "run mode" fairly quickly
the 60 was very rough at closed choke and I had to switch it to "run mode" right away
however, the biggest difference is the RPM, as measured by an inductive tachometer/Hour meter which has an inductive wire looped around the spark plug wire
the 63961 is showing 1800 RPM
while the 63960 is showing 3600 RPM...
yet they both sounded to me as they were running at the same pitch.
I happen to have a third spare tach, and hooked it temporarily to each engine in turn.
the results were about the same 1800/3600 readings (not as stable reading, probably because not as many inductive loops on the temporary tach)
I do not have a scope to measure the sinewave output, but I do have a "true sine wave" UPS.
when hooked to the 63961 and under load the UPS was running off the generator, with an indicated 121V input, and output at 121v and 60-61hz (a bit jittery)
however, when hooked to the 63960 and under load, the UPS switched to battery power, with an indicated 117v input but since on battery power, showed an output of 120v at 60hz
could it be that the two engines are really running at different RPMs even though to an untrained ear they sounded about the same???
or could it be that the 63961 fires up the spark plug on the power downstroke, while the 63960 fires up on both downstrokes???
to me, the 63961 seems "better": better made, and possibly running at a lower RPM,
should I attempt to exchange the 63960 for a second 63961?
or for the sake of redundant redundancy, keep the two different ones?
thanks and a happy new year.
-avi
I am a software guy, and these are my first ever small engines... (i.e. I don't even know what I don't know about small engines)
For redundant redundancy I decided to get two HF Predator generators, so I'll have a hot spare, or if I might need more power.
By chance I ended up getting item# 63960 and item# 63961 (the CARB versions of the 4375)
they look cosmetically different, and they are obviously from a different supplier
from minor stuff such as the 61 gas tank filler is offset to one side, while the 60 has it centered
the tubular frame has the cross members at a different locations on top
the cover of the pull cord on the 61 is red, while the 60 is black.
to some stuff which might indicate better quality:
the 61 valve cover is cast while the 60 is stamped metal
the 61 air filter box is stamped metal, while the 60 is plastic
the casting of the engine body seems better on the 61, sharper corners, vs more rounded off/sloppy casting. (also the etching of the serial number etc seems better/sharper on the 61)
the carburetor also seems better manufactured on the 61
they both started on the first pull (actually not even a full pull)
the 61 kept running at closed choke, though sounded bit "sickly", so I switched the choke to "run mode" fairly quickly
the 60 was very rough at closed choke and I had to switch it to "run mode" right away
however, the biggest difference is the RPM, as measured by an inductive tachometer/Hour meter which has an inductive wire looped around the spark plug wire
the 63961 is showing 1800 RPM
while the 63960 is showing 3600 RPM...
yet they both sounded to me as they were running at the same pitch.
I happen to have a third spare tach, and hooked it temporarily to each engine in turn.
the results were about the same 1800/3600 readings (not as stable reading, probably because not as many inductive loops on the temporary tach)
I do not have a scope to measure the sinewave output, but I do have a "true sine wave" UPS.
when hooked to the 63961 and under load the UPS was running off the generator, with an indicated 121V input, and output at 121v and 60-61hz (a bit jittery)
however, when hooked to the 63960 and under load, the UPS switched to battery power, with an indicated 117v input but since on battery power, showed an output of 120v at 60hz
could it be that the two engines are really running at different RPMs even though to an untrained ear they sounded about the same???
or could it be that the 63961 fires up the spark plug on the power downstroke, while the 63960 fires up on both downstrokes???
to me, the 63961 seems "better": better made, and possibly running at a lower RPM,
should I attempt to exchange the 63960 for a second 63961?
or for the sake of redundant redundancy, keep the two different ones?
thanks and a happy new year.
-avi