New to the forum... needing some general advise.

The boat ran well... I struggled to get it to idle low enough when cold. I couldn’t get it to idle really low when not hot. I got it to idle at about 700rms in gear, 800rps in neutral in the water when hot. I realize I need to get it even lower.
I wasn’t able to mess with the mixing screws as I could get the gage hooked up. I didn’t get the adapter fitting I needed to connect to the back of the carb... (Hose that goes from back of carb to PCV.) Its coming in and I have the vacuumed gage.
Questions:
1.     What is the size hose that goes from the back of the carb to the PCV Valve?
2.     What’s the good top speed? 40ish at sea level?
3.     I want to get various jet sizes. Ill get a stock set as it was changed out. (No idea to what).
a.     Stock is #66.
i.     What’s 1 step richer?
ii.     What’s 1 step leaner?
4.     The stock power valve is 3.5. Should I use stock or just swap in a 6.5?
5.     Any other parts you guys would order?
Thank you!!!!!!! I was super nervous that after all this money spent Id not have a boat that would work… seems it will all work out.

Answers to your questions in bold font.

1.     What is the size hose that goes from the back of the carb to the PCV Valve?

3/8” hose. Go to the local auto parts store and look for the below part. It’s made by a company called Dorman. Leave one the three ends uncut. Cut one end for the 3/8” hose. Cut the last end for the vacuum gauge hose.



2.     What’s the good top speed? 40ish at sea level?

Other people can comment on this, but I think 45 is common.

3.     I want to get various jet sizes. Ill get a stock set as it was changed out. (No idea to what).

Yes, stock is 66. However, main jets will not have an effect on the idle mixture. They control mixture at full throttle (power circuit) and midrange. The power valve decides when the midrange ends and power circuit begins.

Unless you are going to hook up a wideband gauge (is not easy to do on ski boats) and fine tune for a 12.8 AFR at WOT, there is no need to go with jets different than stock.

i.     What’s 1 step richer?
ii.     What’s 1 step leaner?

The term “steps” is misleading.

Idle mixture is typically measured in mixture screw rotations (from the seated position). For example, 2-1/2 turns. More turns counter clockwise is richer.

Power valve is measured by the amount of vacuum needed to open the enrichment valve. For example 6.5 Inches of HG. The higher the number, less engine load needed to enrichen.

Main jet is measuring the diameter of the jet opening. For example, 66 jet is .066” diameter. The higher the number the richer the mixture.      

4.     The stock power valve is 3.5. Should I use stock or just swap in a 6.5?

Try a 6.5. Note, that your gas consumption will increase.

Lots to fill you guys in on:
So the boat has gone to get new upholstery... looks great... Went with grey on blue. Converted the front seats to a bench to allow more comfortable seating. Teak deck was treated and looks great, new carpet, floors were solid… all in all looks great.
Re: idle mixture screws: There is a 1” phenolic spacer with a ~1/2” fitting that goes to the PCV. The hose is special… larger at the carb side and smaller ~3/8” on the PCV side. I placed 3/8” to ¼ adapter and used another adapter from ¼” to 1/8” to hook up the vacuum gage. (Is the Vacuum gage nipple 1/8”?) I plan to order a ½” to 3/8” adapter and get 2 new hoses and then get a 3/8 to 1/8” adapter.
Anyway… screwed the idle mix screws in all the way in and then backed them out 2 full turns. The engine started right up. ~700 RPM out of water. Vac was ~ 15. With some adjustment I got it to 17. Its starts right up and runs great.

So here is my concern. Engine seems great, but I noticed a rust spot between the head and the block on the alternator/passenger side. The boat was in salt water 1 time since rebuilding the head… new seats etc. Do I have a potential head gasket issue? Oh god I hope not.!!!!!!!!