Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Fuel injectors as used by Morgan on the M3W.

If I remember correctly S&S don't put any faith in a compression test due to the easy start cams. Your mechanic may simply have found that the decompressor is working as it should.
If the misfire swapped cylinders with the swapping of the injectors then it does sound like your first thoughts; it's a failed injector.

I”m told by another Morgan mechanic that while you won’t read a full, true compression number, you should read “some” compression.
On the bright side, I now have a new fuel filter, a good spare fuel pump, a spare injector and I did not have to walk home.

The saga continues!! S&S assures my mechanic that the problem is in the cylinder (piston, rings, valves), never had an easy start cam problem.
The mechanic had his doubts and ran the following:
Cranking test showed 50 psi on “good” cylinder, 0 psi on bad cylinder.
Static leak down test showed 85% on “both” cylinders (bad cylinder took some futzing with to find sweet spot for test).
The clincher!! Pulled the exhaust push rod on the bad cylinder (this eliminates the easy start cam) and ran cranking compression test... BAM!! 135 psi on the bad cylinder.
The down side:
You can’t buy just a single cam, they come in sets. The performance cams as sold by G56 are about the same price from S&S as the stockers so there will probably be an upgrade in the future since it will be apart anyway.