BF45 stalls/loses power at 2000 RPM when accelerating

montauk123 · #1 (**permalink**) 07-05-2011, 09:54 AM

Hi, i just joined this Honda forum. Am hoping someone can help. I have an early 1990's Honda BF45A outboard (45 hp 4 cycle). Engine is in good shape, but continually suffers this same problem. It idles fine. But when give it throttle, it starts to lose power and stalls around 2000-2500 RPM. If am lucky, it keeps running and once gets to 3000 RPM, then it runs perfectly again, smoothly powering up to 5500 RPM. It sounded like mid-speed carb jets clogged to me. So have rebuilt the three carbs twice so far, cleaned the fuel lines, changed all filters, new gas, ethanol treatment, etc. But still have same problem. I'm starting to think this may not be a carb problem at all (maybe electrical?) Anyone have similar problem? Any ideas would be most appreciated. Thanks.

Craneman · #2 (**permalink**) 02-21-2012, 12:14 PM

Quote:

Originally Posted by montauk123

Hi, i just joined this Honda forum. Am hoping someone can help. I have an early 1990's Honda BF45A outboard (45 hp 4 cycle). Engine is in good shape, but continually suffers this same problem. It idles fine. But when give it throttle, it starts to lose power and stalls around 2000-2500 RPM. If am lucky, it keeps running and once gets to 3000 RPM, then it runs perfectly again, smoothly powering up to 5500 RPM. It sounded like mid-speed carb jets clogged to me. So have rebuilt the three carbs twice so far, cleaned the fuel lines, changed all filters, new gas, ethanol treatment, etc. But still have same problem. I'm starting to think this may not be a carb problem at all (maybe electrical?) Anyone have similar problem? Any ideas would be most appreciated. Thanks.

Did you get your stalling problem resolved?? I'm havering the same problem
Moe

boats.net · #3 (**permalink**) 02-21-2012, 02:36 PM

If this is a model with an accelerator pump then check to see if synced properly.

psymansr · #4 (**permalink**) 02-22-2012, 08:29 PM

Just joined. Similar problem on very low hours 2004 40 HP 4 cycle (tri-carb). Idles. but stalls when I hit the throttle. Cleaned carbs, new filter, checked lines, fresh gas- no progress! Any advice greatly appreciated. Thanks!!

boats.net · #5 (**permalink**) 02-23-2012, 08:48 AM

Carbs need to be throughlly cleaned(ultrasonic cleaner is best), accerator pumps checked and carbs need to be to sync with carb sync meters after reinstalling on engine.

psymansr · #6 (**permalink**) 02-24-2012, 09:02 AM

I have the carb schematics. The Model is BF 40 LRTA. There do not appear to be accelerator pumps on these carbs. There is something called a "bystarter assembly" which is a small electromagnetic unit on the top carb with a pin that appears to shut off a gas line. I'm wondering if this unit malfunctioning could be the cause of my problems?? Just what is this unit supposed to do? Advice much appreciated!!!
Dennis

boats.net · #7 (**permalink**) 02-24-2012, 10:27 AM

That is the auto choke.