UpwardFl0w
New member
Hi all,
I'm having a hell of a time with this engine. I've got a Honda BF75 7.5hp inboard on a Volvo sail drive leg in my little yacht. It was running fine, but then one day it wouldn't start (despite having run the previous day) and this is where the problems began.
So far I have:
- Replaced the points and condenser and ensured that they are working correctly and are ground standard with opening at TDC breaking the connection.
- Bought a second engine, confirmed the ignition system works, removed the primary coil, ignition coil, and flywheel and fitted them to this engine
- Replaced the spark plugs
- Checked all resistance values of coils
- Removed all wiring except primary coil -> ignition coil -> points
When everything is disconnected, the primary coil generates around 50v AC. As soon as it's connected to the ignition coil and the coil is bolted to the engine, I only measure 0. I've even had a marine engineer out to the boat, and he's as stumped as I am.
I think I must be missing something here. As far as I'm aware, the primary coil generates power and sends it to the ignition coil (which has a single post). This post is connected to the points set, which is closed most of the time. When the points open, it removes the ground on the coil, enables it to energise, and fires the plugs. All of the components individually meet the specifications as defined in the manual. The wiring diagram matches what we have. What am I missing here?
I'm completely tearing my hair out and I'm at the point of hauling the boat out, removing the power head, and swapping it for a complete CDI powerhead from another outboard. I genuinely do not know what on earth I should do next. Any assistance would be very, very gratefully appreciated!
I'm having a hell of a time with this engine. I've got a Honda BF75 7.5hp inboard on a Volvo sail drive leg in my little yacht. It was running fine, but then one day it wouldn't start (despite having run the previous day) and this is where the problems began.
So far I have:
- Replaced the points and condenser and ensured that they are working correctly and are ground standard with opening at TDC breaking the connection.
- Bought a second engine, confirmed the ignition system works, removed the primary coil, ignition coil, and flywheel and fitted them to this engine
- Replaced the spark plugs
- Checked all resistance values of coils
- Removed all wiring except primary coil -> ignition coil -> points
When everything is disconnected, the primary coil generates around 50v AC. As soon as it's connected to the ignition coil and the coil is bolted to the engine, I only measure 0. I've even had a marine engineer out to the boat, and he's as stumped as I am.
I think I must be missing something here. As far as I'm aware, the primary coil generates power and sends it to the ignition coil (which has a single post). This post is connected to the points set, which is closed most of the time. When the points open, it removes the ground on the coil, enables it to energise, and fires the plugs. All of the components individually meet the specifications as defined in the manual. The wiring diagram matches what we have. What am I missing here?
I'm completely tearing my hair out and I'm at the point of hauling the boat out, removing the power head, and swapping it for a complete CDI powerhead from another outboard. I genuinely do not know what on earth I should do next. Any assistance would be very, very gratefully appreciated!