Honda BF50 Timing Issue/Question ??

[boatlessbob]

Can anyone tell me the correct timing for a 2000 Honda BF50AY 4-Stroke. I think I may be a couple teeth off on the flywheel. The service manual is a little confusing. The cam pulley timing mark and the flywheel timing marks line up correctly, but if I look into the cylinder with an inspection camera and turn the flywheel to get cylinder #1 at absolute TDC the flywheel is 3 teeth off. What's confusing is the service manual says to move the cam pulley off by 3 teeth before torqueing down the tension pulley bolt.

This all started after I replaced a burnt charging coil under the flywheel for a tach problem. I took it out to test the tach and it ran and sounded fine for about an hour, but I could never get over 4000 rpm on a new tach. Coming back in, it started sounding like it was missing and the pee hole got blocked. I cleared the pee-hole and water is circulating fine but the engine still sounds like it's missing and it coughs thru the # 3 carburetor. It's fouling the # 3 plug. Looks black but feels more like fuel than oil.

When running the engine, it sounds like the timing is off, and the idle runs high, about 1100-1300 rpm vs 950, verified with an inductive timing light on all 3 cylinders. Compression checked good at 184-184-186 psi. Spec is a minimum of 199 but I'm hoping 184 is good for a 13 year old motor. The leak down test shows 2.5%, 5% & 5% leakage at TDC. The carbs are sync'ed close enough that I'm sure I could mess them up.

Would the timing issue cause it to run fast at idle and foul the #3 plug?

 

[MattFL]

Re: Honda BF50 Timing Issue/Question ??

If it ran fine for an hour and the timing is the same as when you assembled it, then the problem is likely not the timing. Especially if only one cylinder seems to be having problems. Check out the carb on that cylinder and replace the spark plug and make sure you're getting good spark.

 

[boatlessbob]

Re: Honda BF50 Timing Issue/Question ??

Thanks MattFL,

Pulled carbs for cleaning. Went to replace internal anodes and found small pieces of impeller in the water jacket and thermostat area, so am currently in a holding pattern.

Have the boat on a lift. Need to rent a truck to pull it out of the water to replace the impeller or rebuild the water pump. Could be a couple weeks before I know the final outcome.

Thanks for your service. I'm retired Air Force myself.

Bob, Cape Coral

 

[MattFL]

Re: Honda BF50 Timing Issue/Question ??

Save all of the impeller pieces that you find. This way when you take the old pump out, you can determine if you've got any missing pieces still in the motor, or if you've gotten them all out.

No, thank YOU for your service! The "rank" shown by my name on here is specific to this web site; everyone here is given a "rank" based on how many posts they've made, so my rank shown here isn't for the real military. I have not been in the real military myself, but I sure do appreciate those of you who have been.

 

[boatlessbob]

Re: Honda BF50 Timing Issue/Question ??

Thanks again. Didn't think of saving the impeller pieces. Good idea.
Bob