Update: Moving in the right direction!
Tested the alternator and it’s throwing good amperage. 14.20 amps at full throttle. Check that off the list. I purchased a new battery (NAPA 8270) BCI# 27 DCM. It’s 800 CCA @ 32* Check that off too. I did discover that my Voltmeter/Ammeter is not working correctly. It is showing 16. I will investigate that.
I decided to check the valve clearance. So I read the manual and adjusted per the book. Things were ok and seemed to pass inspection. I didn’t like the method spelled out in the manual. Find cylinder 1 TDC adjust valve 1, 2, 3, and 5 (counted front to back) then rotate crank one revolution and adjust 4, 6, 7, and 8. I did that and it looked good. I had never done this quicker method before and didn’t trust it. I had in the back of my mind that spark plugs 2 and 3 never looked quite the same as 1 and 4. Plugs 2 and 3 were not as perfect a burn Pattern and had lots more carbon. Always. I decided to check each cylinder individually as it hit compression at top dead. I found using this longer adjustment method that the valves on cylinderS 2 and 3 were far tighter than they should be. I adjusted each valve so .020 feeler gauge just slips in and .022 will not fit.
Test results:
Prop 14 x 19
RPM slightly above 4400 that’s a 200 RPM increase
Speed 30 MPH
Elevation 4000 feet
Much smother running and far more power felt. We’re moving in the right direction here. Well worth checking this on your boats. I hate to even utter these words but in this case “don’t follow the manual” check each cylinder individually. That Manual method may work somewhere or be a quick get it done shop trick but it didn’t work here.
Side notes I noticed testing: These tests were with me in the boat (6’4” 250 pounds) I added my dad, later in testing, who is also 6’5 260 pounds and we noticed a slight drop in RPM and Speed. To be expected but interesting. 4300 or so RPM and 29 MPH. I made note that adding about 250 pounds to the boat will cut RPM by about 100 and Speed by 1 MPH.
Boat still has dirty bottom and that will be tested at some point later.