Skipper Dude -
As the others have already said, there is a LOT more to the story than what that "mechanic" told you. He neglected to tell you about pop pressure, spray pattern, carbon build up, etc.
I pulled all my injectors last winter on my 1982 Lehman 120....had 6500 hours on it.
What I found was the bleed off line was INCORRECTLY attached to the injectors by some "mechanic" before me. See here to know what I am talking about
The bleed off tube was crooked when mated up to several injectors. THe pictures show it. You can see how the bolt head is cocked and not flat to the bleed off tube ring. The screws that hold the bleed off tube into the injectors were CROSS THREADED !!!! What a NUCKLEHEAD that "mechanic" was ! So the bleed off tube was NOT holding the bleed off fuel as it was supposed to.
Took them all to a shop to be tested and rebuilt if needed. Shop calls me and says "Yeah they needed to be rebuilt because the threads were crossed and the nozzles were all crapped up. BUT they are all popping at the correct pressure."
So I ask them how they know what the correct pressure is, because they didnt know what engine they come from. Turns out the rebuilder looked them up in book to get the pop pressure. BUT, his looked up pop pressure was only 2/3 of what the Lehman book said it should be ! So I tell him NO! Set the pop pressure at what my Lehman manual says it should be (and I told him the correct pressure).
So be careful when dealing with "mechanics" and I especially shutter when boaters use the term "had it done by a professional".