Honda BF130 # 2 cylinder @ low RPM

[lake vermilion]

I am a brand new member & WOW some great knowledge on here. I have a 2000 Honda BF130 that has a bizarre # 2 cylinder problem. It started last fall at trolling speed around 1000 - 1200 RPM's I noticed it sounded like it had a miss but once above 2000 RPM's it would smooth out & continue to run just fine at WOT 5000 - 5000 RPMS. If I pull the plug on # 2 when it happens there is NO change still has the miss but if I do it to #1, #3, #4 it wants to fall on its face. SO I suspected # 2 Plug, plug wire, coil, or fuel injector. Well I had the injectors professionally cleaned, after the cleaned injectors were installed everything is still the exact same. I have changed plugs, swapped plug wires between #2 & #3, had #3 wire from coil go to # 2 plug & vice versa. I connected # 2 injector to #3 injector wiring & vice versa. I pulled the plugs & had my son crank the engine to test compression with a cheapo compression tester. #1 - 150, #2 -125, #3-150, #4-150. I put the boro-scope in all of the cylinders & #2 does not look any different than #1, #3, or #4. #2 has a 25lbs lower compression but I still have the same thing going on ???? I have done a lot of compression tests over the years but I have never had 25 lbs or similar on 1 cylinder cause this. I am stumped. Has anybody heard of anything similar? Thank you in advance for any insight

 

[hondam]

Compression tests on Honda engines are different, you have to do the test with the throttle at WOT or you may get inaccurate results. A leak down test would be better.

Fuel pressure needs to be about 40psi, if you have never changes the High Pressure filter you should probably get a new one, its easy to change on that engine.

Those motors are a little harder to work on because even though they are fuel injected the computer will not communicate with them. My suggestion, get yourself a service manual because you will probably need to do some electronic testing. Also with the age of the motor it might not be a bad idea to do a valve adjustment.

 

[lake vermilion]

Thank you for the response. I had changed the high pressure filter last fall. No improvement. I will definitely check & adjust valves this weekend. & redo compression test at WOT. What do you mean by computer won't communicate with the injectors? I do have a clymer shop manual I also did a shock treatment with Yamaha ring free just before I shut it down for the weekend so I will need to change the oil & try to figure this out

 

[hondam]

I mean there is no computer diagnostic tool for that engine.

 

[lake vermilion]

Oh gotcha Thank you. Going to do the leak down test this I will post the findings