Interceptor Starts After 15 Year Storage 57 312ci 215hp

I got the 312ci 215 hp Interceptor started today. New boat to me, I installed new plugs, plug wires, distributor cap. I cleaned the Carter YH’s as best I could without removing them. Fuel was leaking out the rear carb so I checked the floats and they were set below spec. I set them 1/16 above spec and this stopped the leaking out the rear carb. Spec is 9/16 for the front and 1/16 for the rear.
I used up 2 gallons of premium with CD2 added before I ran out. She is running a little rough and smoky. Black powder soot in the pipes, maybe running too rich. Maybe need a new coil too. Old one looks like it’s 53 years old.
I installed two new 142 degree thermostats. Found these at Napa. They are part # PCM RP026002E. These fit just fine after grinding the flange diameter to fit. They didn’t open with using up two gallons of fuel. I’m using a fake-o-lake plunger. Do these really work? I wonder if my impeller is working. Any easy way to tell?
The boat is a 57 Century Arabian. It’s in great shape, shinny varnish and solid bottom. If I can get the Interceptor running smooth I should be able to launch soon. It’s great to hear an old boat, she sounds really cool.

Type o on rear carb spec, should read 7/16.

The 57 Arabians are great looking boats, we have one in our little collection waiting to be restored! The 312's are great engines and the off set reduction gear box is fabulous if the oil is changed religiously!! All 5 of our Century's have the 312 with reduction set ups, we use our Resorter 18's for skiing and hope to get our 57 Coronado done with in the next year and a half (will be our vacation boat) Best of luck with your Century and 312!!!

If you need replacement Engine decals let me know as I have them available!

and yes I agree with you, these old boats sound amazing on the water! Cant beat an old wood boat, whether you are going for a ride or skiing behind one...they are simply amazing boats!!!

Thanks shilpisch, my decals are mostly gone. Looking at aftermarket valve covers I haven't seen any with an oil fill or breather.
There is a 71C Muncie Velvet Drive in my boat. Tonight I took off the Dearborn water pump. Guess I need a puller to get it apart. It appears to be working.
If I fill it with water then spin it water rushes out the left up tube.

Michigan boat

I rebuilt the Carter YH carburetors this week. They looked good except for the accelerator pump diaphragms which were badly eaten. Replacing these, hope this solves my smoking exhaust problem.