Picked up this compressor today

[88sub4x4]

I picked up this compressor today. It has a twin cylinder pump and a 5.5HP Honda engine. Runs great. Wasn't looking for a gas unit, but I don't have proper electric to run a 220V unit at my house. Need the electric co. to run some new wires down the street. Anyway, got it for 300. Thought that was a good deal. I need to weld some reinforcement to the motor mounting plate because of the crack. Also had to put new gauge and coupler on due to leaks. I have never used a unit like this before. It runs until the pressure reaches 160psi, then the engine idles down and air purges out of somewhere for a few seconds bringing it down to 120psi, then the engine revs up again and pumps to 160. This cycle continues over and over. Is this how these units are supposed to run? I think it is supposed to stay at 160 until I use some air and when it gets down to 120 it should kick back up, but am I wrong? Please school me on this. The third pic is of where the pressure line runs to the carb to kick the idle on and off. Not exactly sure how this works either.
Thanks for any advice guys

 

[88sub4x4]

Here is a pic of the crack.

 

[diesel4me]

good score..

A compressor like that is hard to find for less than 500 bucks with a Honda motor on it...you did OK!..

Most compressors with gas engines are "continuous run" --they do just as you said,pump up to the maximum pressure allowed by the pressure switch,then a valve opens to let the pump "frewheel" instead of pumping more air,by holding one of the valves in the compressor pump open...then after pressure drops below a set PSI,the valve closes again,and lets the pump pressurize the tank again..and the cycle repeats over and over..there is a safety "blow off" pressure relief also,if for some reason things dont work properly,that will not let the tank over pressurize (all compressors have one)..

The throttle is controlled by a small air piston on most gas powered rigs..when the maximum PSI is reached,and the valve opens in the pump to let the pump frewheel,it also sends air to that little piston,which kicks the throttle back to idle..when it starts pumping again,that piston loses its air pressure,and the govenor takes over the engine RPM speed..

I wanted to convert a huge 7.5hp compessor I have with a 3 phase motor, to a gas engine--I put a 25 hp 2 cyl.Onan motor I have on it,but the valve I'd have needed to make it run like yours costed nearly 200 bucks for such a huge CFM pump,and when I tried the gas engine,it seemed to be laboring too hard as pressure built up in the tank--and I couldn't re-start it once it was "pumped up"..head pressure in the pump wouldn't let the starter crank the motor!..(that valve I needed may have solved that trouble,but I decided to put the 3 phase electric motor back on and try to sell it instead)..I was hoping to use it for sandblasting,without running up huge electricity bills..

I think your better off with gas power--its portable,can use anywhere with no power cords or electricity,and is probably cheaper to run!..Honda motors last forever and are very quiet too..those "hot dog" tanks recover quickly,you can run impacts and air tools quite well with them..

 

[88sub4x4]

Thanks alot for all the info

It seems to be working exactly as you stated. I wasn't sure if it was supposed to hold the air from bleeding off, but it seems that is the way it is designed. I plan to weld up a new mounting plate this weeked, change all the oils, and get some wheels for it, and I should be good to go.

The only downside to the gas at this point is I won't be able to do late night wrenching with the noise, but this is the best I can do for now.

Thanks again for the info!

 

[chevyfumes]

Onboard air...

 

[88sub4x4]

Don't laugh......I've seen guys do that!

Unfortunately this is too heavy to lug around in my Jeep

 

[diesel4me]

muffler...

Can't see the muffler on it,but if you could adapt a regular car muffler onto it rather than the stock one,you can reduce the noise level quite a bit..

I put a muffler from a small 4 cylinder car I had kicking around ,on my 5hp Tecumseh generator I made for charging/jump starting cars with a GM alternator and a battery---its so quiet now I can hear the valves clicking!..I'm not afraid to run it anytime I need it--its a lot quieter than the 6.2 diesel in my truck!..Usually Honda's stock mufflers are pretty quiet too though--maybe yours burnt the baffles out??..

 

[88sub4x4]

Thats a good idea. Going to have to look into that one. It's supposed to warm up a bit this weekend, so I should be able to get out there and play with it a bit.
It's not that this is really loud, but I have neighbors really close to my garage that have small kids, so I don't want to be making noise late into the night. I get along fine with them and they don't complain about my never-ending stream of junk i work on, so I like to keep them smiling!

I'll post up some repair pics when I get this thing fixed up and running properly.

Thanks again!

 

[beater_k20]

i've got one with a 5.5 Honda on it too, a little lower profile than yours. its paid for a junkyard trip or two in its day. works great at the derbies too. dont know what my buddy paid for it, but i got it as payment for a $300 loan i gave him. almost brand new too.