"Tough one here: 2006 Honda BF
"Tough one here: 2006 Honda BF75. One way or another, I got a tank full of bad gas/water in the tank (I hate E10), needless to say the engine ran very poorly. I drained/flushed the fuel tank, new fuel filter on the engine, new water separator on the boat. Pulled the intake manifold and carbs. Rebuilt the carbs without changing any adjustments. Everything looked brand new, no obstructions, but I soaked everything in SeaFoam and dried with compressed air anyway.
Same old story right? This is where it gets interesting. After a careful reassembly, the engine ran great for the next three trips. Total run time was probably about 2 or 3 hours, but plenty of time for this to show up. On the 4th trip, it starts to run rough and I can tell that it's missing.
Troubleshooting:
I discover that on start ups it runs fine (purrs like a kitten). I blip the throttle. Every third or fourth time I do this, it starts missing. I can make it go away by blipping the throttle a few more times.
By process of elimination, I discover that the missing cylinder is #1 (Top). But again, I can make it purr or miss just by blipping the throttle.
-All cylinders have good spark (even #1 while missing).
-All spark plugs have been replaced.
-Compression test was good on all cylinders.
-All valve clearances are within limits IAW Honda shop manual.
-All throttle cables are adjusted IAW Honda shop manual.
-I have not had the carbs synchronized since the rebuild, but, I made no adjustments, and it idles perfectly upon start up. If it needed a sync, how could it go from missing to running great just from a blip of the throttle.
-I have tried to find intake manifold and carb gasket leaks by spraying carb cleaner in the area while running with no joy.
-I pulled and tested the thermostat, thinking unequal heating of the cylinders, it checked good.
-Swapped the coils, problem stayed with #1 cylinder.
-I've ran the engine with a separate fuel source to cancel that out of the equation also, no joy.
I searched this site and others with no joy and I'm close to being defeated. I don't want to go to a dealership, but I'm at that point unless you guys have any ideas."
"Tough one here: 2006 Honda BF75. One way or another, I got a tank full of bad gas/water in the tank (I hate E10), needless to say the engine ran very poorly. I drained/flushed the fuel tank, new fuel filter on the engine, new water separator on the boat. Pulled the intake manifold and carbs. Rebuilt the carbs without changing any adjustments. Everything looked brand new, no obstructions, but I soaked everything in SeaFoam and dried with compressed air anyway.
Same old story right? This is where it gets interesting. After a careful reassembly, the engine ran great for the next three trips. Total run time was probably about 2 or 3 hours, but plenty of time for this to show up. On the 4th trip, it starts to run rough and I can tell that it's missing.
Troubleshooting:
I discover that on start ups it runs fine (purrs like a kitten). I blip the throttle. Every third or fourth time I do this, it starts missing. I can make it go away by blipping the throttle a few more times.
By process of elimination, I discover that the missing cylinder is #1 (Top). But again, I can make it purr or miss just by blipping the throttle.
-All cylinders have good spark (even #1 while missing).
-All spark plugs have been replaced.
-Compression test was good on all cylinders.
-All valve clearances are within limits IAW Honda shop manual.
-All throttle cables are adjusted IAW Honda shop manual.
-I have not had the carbs synchronized since the rebuild, but, I made no adjustments, and it idles perfectly upon start up. If it needed a sync, how could it go from missing to running great just from a blip of the throttle.
-I have tried to find intake manifold and carb gasket leaks by spraying carb cleaner in the area while running with no joy.
-I pulled and tested the thermostat, thinking unequal heating of the cylinders, it checked good.
-Swapped the coils, problem stayed with #1 cylinder.
-I've ran the engine with a separate fuel source to cancel that out of the equation also, no joy.
I searched this site and others with no joy and I'm close to being defeated. I don't want to go to a dealership, but I'm at that point unless you guys have any ideas."