Honda BF-150 Knock Sensor

[stevek185]

So I took my boat to the Honda dealer last week to have the port motor checked out due to the check engine light coming on. After looking through everything, looks like the fuel hose was the wrong size. There was a 3/8 coming from the water seperator to the bulb. Bulb is a 5/16 and the line from the bulb was a 5/16. The dealer that I purchased from had it rigged that way. They had tried to clamp the 3/8 hose to the 5/16 bulb, which caused a small leak just before the bulb. Can someone tell me why this would cause the engine to knock? BTW - I had them change the lines on both the port and starboard engine.

[PatrickG]

So I took my boat to the Honda dealer last week to have the port motor checked out due to the check engine light coming on. After looking through everything, looks like the fuel hose was the wrong size. There was a 3/8 coming from the water seperator to the bulb. Bulb is a 5/16 and the line from the bulb was a 5/16. The dealer that I purchased from had it rigged that way. They had tried to clamp the 3/8 hose to the 5/16 bulb, which caused a small leak just before the bulb. Can someone tell me why this would cause the engine to knock? BTW - I had them change the lines on both the port and starboard engine.

Funny. We had the same issue during the first 50 hours on our Honda BF-150. We would run fine at 4000-4500 rpms. When we got close to the marina and decided to open it up for a little bit the engine would die. It ended up being the same issue as yours. It was a pin size hole that would only open up when it was drawing a lot of fuel.

Back on Subject:

There is so much technology in your engine it is difficult to tell what was causing your engine to read a knock. It could be caused by using lower octane gas. It is likely that the lower fuel suction caused a lean air/fuel mixture. Running an engine lean typically causes detonation.