I have a 1972 Columbia 30 which has an atomic 4 with a Walter V-drive and 2:1 ratio. Under the coil, the engine bears the stamp UJ-5 UF (The U and F are overlapped) as in my attached photo.
My question is regarding my prop. It is a 15 x 9 RH prop and the C-30 owners manual called for a 16 x 9 RH prop.
Does my prop have to work harder than a 16 x 9 prop to move the boat 9 inches forward, and result in more load on the engine trying to push the boat, or do I simply have less push from the prop?
On a separate note I have been suffering the issue of shutdowns after 1 hr. of cruising and read the notes re. adding a ballast resistor before the coil to protect it and the EI from getting fried. I used Neil's spreadsheet formula and bought a 1.2 ohm resistor.
I was going to put the resistor on the plus lead going into the coil but have read elsewhere on the forum that when other circuits are also using this plus terminal to supply 12v to whatever, that the resistor needs to go on the minus lead (black) between the coil and the EI
Doesn't this mean that the resistor is now after the coil and not doing what it intended for?
Surely if I fit the leads from the plus side of the coil to the new resistor, and the other end of the resistor to plus side of the coil, only the coil will be affected by the resistor .
Any advice appreciated.
My question is regarding my prop. It is a 15 x 9 RH prop and the C-30 owners manual called for a 16 x 9 RH prop.
Does my prop have to work harder than a 16 x 9 prop to move the boat 9 inches forward, and result in more load on the engine trying to push the boat, or do I simply have less push from the prop?
On a separate note I have been suffering the issue of shutdowns after 1 hr. of cruising and read the notes re. adding a ballast resistor before the coil to protect it and the EI from getting fried. I used Neil's spreadsheet formula and bought a 1.2 ohm resistor.
I was going to put the resistor on the plus lead going into the coil but have read elsewhere on the forum that when other circuits are also using this plus terminal to supply 12v to whatever, that the resistor needs to go on the minus lead (black) between the coil and the EI
Doesn't this mean that the resistor is now after the coil and not doing what it intended for?
Surely if I fit the leads from the plus side of the coil to the new resistor, and the other end of the resistor to plus side of the coil, only the coil will be affected by the resistor .
Any advice appreciated.
Comment