Honda BF20: "Pulsating" power delivery in one-second intervals. Briefly works fine if restarted.
We have a Honda BF20 bought new about 5 years ago. It's always been used as the auxiliary outboard on a large boat, but this year we have it installed as the main outboard on a 12-footer.
Today was the maiden voyage as main engine. Outboard started fine and ran perfectly as usual, but a few minutes in, it lost power and started running erratically. Basically it would run at the set throttle setting for about one second, then give no power for a second, then accelerate back to the correct power for a second, over and over. It's like someone was opening and closing the throttle repeatedly in brief intervals.
After 20 seconds of running badly, the motor would cut out. Then it would start on the first pull of the rope and run fine for the next 2 minutes, then once again it would lose power with no warning and repeat the above.
Closing the throttle while it's acting funny results in a smooth idle. Opening the throttle just a little (say, 100rpm above idle) gives normal running. Opening it a little more it would start to pulse the power again.
Here's the funny thing. If it starts acting up and I kill it with the red ignition-cut button on the tiller, then start it immediately, it would run fine for a few minutes until it starts missing again. But once it starts missing, nothing I tried would get it to run right again short of killing and restarting it (or waiting for it to die of its own accord and then starting it).
The fault would appear after a few minutes at any power setting - WOT, half power, trolling etc.
Thinking it was a fuel problem, we tried running with a different fuel tank and fuel line. Still same problem. So it's likely something within the outboard that's not right.
We have a Honda BF20 bought new about 5 years ago. It's always been used as the auxiliary outboard on a large boat, but this year we have it installed as the main outboard on a 12-footer.
Today was the maiden voyage as main engine. Outboard started fine and ran perfectly as usual, but a few minutes in, it lost power and started running erratically. Basically it would run at the set throttle setting for about one second, then give no power for a second, then accelerate back to the correct power for a second, over and over. It's like someone was opening and closing the throttle repeatedly in brief intervals.
After 20 seconds of running badly, the motor would cut out. Then it would start on the first pull of the rope and run fine for the next 2 minutes, then once again it would lose power with no warning and repeat the above.
Closing the throttle while it's acting funny results in a smooth idle. Opening the throttle just a little (say, 100rpm above idle) gives normal running. Opening it a little more it would start to pulse the power again.
Here's the funny thing. If it starts acting up and I kill it with the red ignition-cut button on the tiller, then start it immediately, it would run fine for a few minutes until it starts missing again. But once it starts missing, nothing I tried would get it to run right again short of killing and restarting it (or waiting for it to die of its own accord and then starting it).
The fault would appear after a few minutes at any power setting - WOT, half power, trolling etc.
Thinking it was a fuel problem, we tried running with a different fuel tank and fuel line. Still same problem. So it's likely something within the outboard that's not right.