Also check the secondary and you may need to adjust the throttle plates

actually its a brass disc that goes to th lug to make contact you will see when you take it apart.

Be sure the air bleeds are clear, spray wd 40 ocassionaly to keep clean.

You can take the solonoid apart and there is a brass lug. The lug gets burned from starts, you can turn it around, or clean off the lug . Me I would just turn it around and use the other side.

Glad to hear that, when you have close calls such as he has. His body and mind are telling him it's time. I spent 20 years in the East driving the the fastest , ERR, E&F service, ski, SS. I roled a 16 ft Patterson in Dayton, OH in the ski divisionals.It drove from the right side and always wonder how I ever would come out well I did. Did a simular roll like Tony, luckly came out ok put a hole in the deck with my head. However I continued to drive but always had the flip on my mind every time the boat made a motion. When you have these things on your mind and not soley on driving it's time to leave. He has nothing to prove, hard charger.

The differene of a marine carb is the vent tubes, if the carb over vents the fuel goes directly back into the carb rather than the boat. You can buy them ( J tubes) from holley or make them.

To add more Carb or CFM depending on the modifications may add maybe 5 HP however you want to improve on the VE volemetric effeciently. Again the mods, heads,cam,intake manifold, comp, etc are necessary to increase the VE. The formula to figure CFM is pretty much a good indicator.
Remembering that at 5250 is where the hp and torque meet . EX. Given all the facts 750 to 850 CFM more carb can give raise the HP 5 hp and raise the VE from 88 to 90 %

Salesmen, I asked what the "W " meant  on the label. He had no answer he didn't know and this was with a reputable oil distributor.
So what I am reading here are direct quotes from written passages, which is good. The more knowledge the better understanding of oils.
Growing up we were in the transportation business and the knowledge of oils was terrible. We used about everything coming down the pike. In those days they all wore ten gallon hats and criticized every body's product. We learned the hard way we were getting engine changes instead of oil changes. We thought the more expensive was better, not true, the oil not being no detergent was in fact 13% detergent and was ruining our engines. Remember 60 years ago things were different and paraffin oils was getting scarce and asphalt base oil came into the market now synthetic, quite a change. So too really understand what you are using is important. Remembering the most expensive is not necessarily the best for your application. There is a world of difference in engines, two stroke, four stroke,gas powered, diesel powered, propane powered that use all difference base oils. I agree light weight oil flows better returns faster and needs less power distribute the flow, so now the properties in the oil are very important especially in sever conditions.

I ran the 390 FE in my F- Service boat, I believe the crate engine from Ford was 375 HP. We used to turn the engine 6000 rpm during marathons thru  V DRIVE.

Sorry, must have been another post, he had a hydraulic lifter cam

Whatever oil you choose to run has to form a film or cushion of oil to keep the the bearing off the journals. The pressure keeps the oil with that film to do so. If the pressure becomes too low it can't do so and the bearing drags on the journal causing wear. The clearances of the bearings is what determines the viscosity to supply need to form this cushion.
The viscosity of the oil under severe heat is needed to keep this cushion up, so if 15-40 or a 20-50 is used the first number is what is performing the job, the second number is what it does under severe heat and usage to maintain the the job the first number of the oils weight.

After years on the race circuit I have found on oil lines even with push lock fittings will come off. Now some will say BS however have seen it and had it happen to me. So I add clamps to the lines and safety wire all fittings. Same goes with water fitting they also fly off. I check mine every time I go out to be sure, engines are too expensive to replace. Call it preventive maintenance, just my .02 cents.

All oils have their place in the market however the zinc has been removed or lowered in most oils.I myself use Shell Rotella 15-40 and does a great job. It is recommended for all types of Diesel engines. It is used in Diesel engine's that demand more than a car or boat needs. A can of zinc additive added will cover that problem.
A diesel engine use 15-18 - 1 compression and close bearing clearances. Severe heat is also a factor in Diesel engines.Temps normal 200-212 , oil temps are also high.The wear on a diesel rod and crank is on the top shell due to the high compression and when you take them apart the bottom looks like new. Difference ,If this oil can suffice for those engines it will work just fine in the boat.
For the oil to do its work everything in the installation of the components, has to be precise if not at that point it doesn't matter what price the oil is.