toddster541
Registered
I recently picked up a used MaxAir 35. This unit was new in 2006 and allegedly has less than 50 hours run-time (the hour meter battery had gone dead.) It has mostly been riding around, bolted to the deck of a sailboat in the Sea of Cortez, or sitting in a garage, since then. The previous owner had the Honda motor serviced and all of the rusted bits, including the carb, replaced by a small engine shop about a month ago. It seems to run fine, although the max RPM I get from it is about 3200 instead of 3500.
I've cleaned up the compressor, replaced the hose, gauge, hour/tach meter, and a few missing frame screws. Changed the oil, which looked clear, but there was a streak of dark matter that pooled at the bottom of the pan - not course enough to recover any particles - more like a bit of soot.
So: it pretty consistently takes 35 minutes to fill an aluminum 80. Which works out to more like 2.3 cfm than 3.5. The 10% low motor RPM can't account for that much loss. Belt tension seems OK, but I haven't put a new belt on. The back pressure valve opens at 1000 psi. The relief valve opens at 3000 psi, rather than the 3300 it is supposed to be set at. If I pump it up to 200 bar (just before the valve opens), I can't find any leaks around any of the fittings, using soapy water. But still it gradually leaks down over about an hour or two. I kind of suspect the relief valve, since after opening, it gradually sorta closes when the system leaks down to around 2200 but there doesn't seem to be a definite shut-off. Though I don't get soap bubbling on the outside of it. Not sure what the normal behavior looks like for this valve.
Since I'm currently using aluminum 80's and rarely need to fill more than two tanks in a day, the compressor more or less is doing what I need it to do. So I don't wan't to start throwing expensive parts at it. But it doesn't seem quite right...
Any ideas what to try next? Don't worry, be happy?
I've cleaned up the compressor, replaced the hose, gauge, hour/tach meter, and a few missing frame screws. Changed the oil, which looked clear, but there was a streak of dark matter that pooled at the bottom of the pan - not course enough to recover any particles - more like a bit of soot.
So: it pretty consistently takes 35 minutes to fill an aluminum 80. Which works out to more like 2.3 cfm than 3.5. The 10% low motor RPM can't account for that much loss. Belt tension seems OK, but I haven't put a new belt on. The back pressure valve opens at 1000 psi. The relief valve opens at 3000 psi, rather than the 3300 it is supposed to be set at. If I pump it up to 200 bar (just before the valve opens), I can't find any leaks around any of the fittings, using soapy water. But still it gradually leaks down over about an hour or two. I kind of suspect the relief valve, since after opening, it gradually sorta closes when the system leaks down to around 2200 but there doesn't seem to be a definite shut-off. Though I don't get soap bubbling on the outside of it. Not sure what the normal behavior looks like for this valve.
Since I'm currently using aluminum 80's and rarely need to fill more than two tanks in a day, the compressor more or less is doing what I need it to do. So I don't wan't to start throwing expensive parts at it. But it doesn't seem quite right...
Any ideas what to try next? Don't worry, be happy?
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