Originally Posted by Billybob

Are you certain the prechambers are compatible? The OM616 used a couple of different types over time; some are not interchangeable with others as there are different piston configurations.

One thing to do is to check the EPC using your car's VIN for the Data Card, then verify that the original engine is in the car. You can then do parts check for the correct prechambers for the engine you have, get that part number and do a Part Number search checking for cross compatibility with other engines.

Up here in MA with some pretty crazy enviro regs the one gallon can with basket GUNK Carb/Parts cleaner is still on the shelf at AutoZone as of a couple months ago. That stuff softens carbon type fouling pretty effectively.

Gunk CC3K Carburetor & Parts Cleaner with Drip Basket - 96 fl. oz

Amazon has it about $23 plus shipping and Ace Hardware lists it for a couple dollars more, O'Reillys, Grainger

Looks like FL Auto Zones carry Berryman/1 gal. B-9 carburetor and parts cleaner with basket $27.99

The prechamber holes are pretty specifically sized I’ve used wire gage twist drills of the correct or slightly smaller diameter to clean them after soaking the prechambers for a while