Hello
Could anyone tell me if the Volvo penta AQ151B has a ballast resistor and where it may be located. I believe it has it and I think I've got the wrong ignition coil fitted. I've got a 3 ohm coil fitted.
pull the distributor cap. if you have points, you should have a ballast resistor or ballast wire. if you have electronic distributor from volvo, then no ballast resistor/wire.
if aftermarket pertronix, it will need a ballast resistor.
Another way is to measure the voltage at the + or bat side of the coil with the engine running. Readings around 8-9 will show a resistor and of course readings of 12 volts will indicate no resistor.
Also many boat builders did not use the genuine Volvo instrument and harness to hold down the price of the boat. This only is on the Volvo inline engines. These do not have a “bypass” circuit in cranking mode. If you measure the + or bat side of the coil in cranking mode you will not have full battery voltage fed to the coil which makes starting sometime hit or miss. The cure is simple, look closely at the starter solenoid and you will see an unused male spade connection. Make up a wire from the spade connection and connect the other end to the + or bat side of the coil, this usually makes a difference and the engine starts quicker.
