by John
(Steinbach, Manitoba, Canada)

It is a Fini-Biscout MK200-1.5M dual tank compressor runs on 120V which I purchased new about 20 years ago. Compressor has been used very very little but it had always worked well even running framing nailers.

It builds up to normal operating pressure as it always did and shuts off at correct pressure.

However when using it unloads air at normal pressure but quickly pressure drops to where the tools don’t work.

If you continue to hold tool trigger switch, slowly it starts discharging air again until it hits normal operating pressure but does not last very long and then drops off till pump kicks in to build up pressure again.

It just repeats this cycle.

Haven’t done anything to diagnose yet and I’m not very knowledgeable about trouble shooting this.

To me it looks like it is unloading one tank at a time with perhaps a blockage between the tanks preventing a continuous discharge of air?

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Fini-Biscout MK200-1.5M
by: Bill

Be nice to see a photo or two of your compressor!

When I started reading your post I thought that here was another undersized air compressor.

Yet if it has worked well in the past, something has changed on your Fini-Biscout MK200-1.5M John, as you have noted.

Possible blockage between tanks? Maybe, but unlikely.

I’d tend to look to the regulator malfunctioning.

Maybe try pulling air after you’ve removed the regulator?

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Some more info on my Fini Biscout
by: John

Did some checks this afternoon relating to regulator comment.

I found that the 2 gauges don’t make sense.

Max tank pressure was 142 PSI @ cutoff and line pressure was 162 @ cutoff.

As I mentioned initially line pressure would bleed down with tool usage to almost nothing still showing about 135 PSI line then slowly come back up to tank pressure but watching line pres. @ regulator I heard the sound of diaphragm letting go and a thump and then line press. quickly jumped, drained down with tool usage and compressor restarted.

Could the diaphragm be sticking in the switch and can it be cleaned and re-lubed?

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Fini-Biscout issues
by: John

Well it looks like the one suggested probable fault was spot on. Replaced the regulator and now it functions properly again although it seems to take longer now to bring the compressor up to max pressure. I can live with that. Thanks. for your help.

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Solved.
by: Bill

Glad to hear it John, and you are certainly welcome.

Slower than normal build pressure points to, among other things, pump valves, pump gaskets, piston seals. Good luck.


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