BF50 2003 coil measurements

I have a problem with a 2003 model BF50 - cylinder #2 misses at idle, runs ok at higher rpm. I've drained the carb for that cylinder, changed plugs, pulled #1 & #3 out, leaving #2 in, felt the compression when turning flywheel.

I pulled the rack with the 3 coils - measured resistances - all the primaries are the same, about .5 ohms - measuring from the spark plug caps to the ground terminal, #1 & #3 measure about 14 k ohms, #2 measures 12.45 k ohms. Does the coil sound like my problem?

It is hard to tell if it is the problem. Easiest way to check is to switch another coil with the potential problem coil and see if the problem follows the coil....but before you do read the following...

Have you performed a cylinder drop test.....as the engine is idling, pull each spark plug wire one at a time and see if the motor rpms drop. If it does, then that cylinder is firing, if it does not, hold the plug wire cap just over the spark plug and listen for the tick, tick, tick. If you here the tick, you have spark. Use insulated pliers for this.

If you have a cylinder that fails and there is still spark, then forget about the spark coils.

Carefully remove the plastic choke linkage #17, that runs vertically between the carburetors. http://www.boats.net/parts/search/Honda/Outboard Engine/2003/BF50A3 LRTA/CARBURETOR/parts.html

With everything put back together, very slowly, manually operate the choke lever for the problem carburetor. Don't operate it all the way....operating just a little will probably get the cylinder to fire. If it does, then, at least the idle circuit in the carburetor is clogged.

Mike

Mike, thanks - I'll try that - but it does have spark on the dead cylinder. So, I'll try the "disconnect the choke" thing as soon as it quits raining here - probably tomorrow.

Another question: If I remove the carburetor carefully and don't disturb the adjustments, must I do the "synchronize" thing? No adjustments on this engine have been disturbed.

Bill

Theoretically, if it is in sync now, putting it back in the same location without changing the sync adjustment, it should be ok.

Of course, I have to say, since you do not know if the sync was correct before, it is always recommended that it is sync'd when all in finished.

I have found in a few cases , just synchronizing the carburetors gets the bad cylinder working. I will say that happens more with Yamahas than any other motor.

Mike

Thanks, Mike --- still raining, so I'll get to it when it clears up. This motor has been babied and never molested, on the "if it works, don't fix it" theory - I've replace the plugs, oil, filter, lower unit grease and an auxiliary in-line fuel filter every year. The impeller has been replaced, probably needlessly, a couple of times. It's been used very lightly, and has always run flawlessly. It started this missing at idle the last time I used it last season. After verifying that the ignition is ok, I'll take the carb off and clean it out. Thanks again for all your help.

Bill