There is no "interior lining" except the cadmium coating. The rebuild kit includes new jets, who cares about the blocked ones. Gas can not remove that coating. What happens is when you let the boat sit with gas in it for extended periods of time (6+ months) the gas coats everything in a thick film of varnish it's nearly impossible to clean but not impossible when soaks for a few days. You can let any gas made sit in there for 20 years and it will not remove that plating. It's chemically impossible.
That engine should have a 4 barrel on it. If not I can get you the part numbers for the 2 barrel. The good news is, a new carb is not $1000. It's only $425. IF not, the 2 barrel is even cheaper.
http://www.summitracing.com/parts/HLY-0-80492/
The rebuild kit is $25 http://www.race-mart.com/Holley_Perform ... 03-29.html
EVEN better news is: Give your mechanic the middle finger, hook up your boat and tell that dishonest cheat to go suck himself. Buy the rebuild kit for $25, do it yourself it's easy. It will run like new. In a rare instance if you did let it sit and it's all gooped up, take it all apart, stick it in a bucket of carb cleaner (buy it at NAPA) and in a few days scrub it down good with a wire brush and install the rebuild kit. Will run like brand new.
Welcome to the forums
PS, get used to installing refresh kits. If you use your boat weekly, you can do it every 1-3 years for optimal performance and gas mileage. If you use your boat every 1-2 months, do it once a year to avoid downtime of clogged holes from gas varnish. It's part of the maintenance schedule of owning a boat with a carb. Get used to it. If you run pump gas E10 throw a main jet in that's 2 sizes bigger then stock, it will run even better then off the showroom floor.