BF 50 Struggling at Idle

Sounds great, thanks again Jmgo.

I am going to buy the sync tool, and in the meantime, I am going to buy a spare bottom #3 carb. Its not THAT expensive, and cheap insurance in case I have an issue getting the screw out with a dental pick or easy-out. I am having trouble finding out exactly which part number this bottom carb is -- the honda parts list is very confusing. On the parts diagram, I know what I need is part #17, but it is unclear WHICH #17 model I need (there are at least 3). I figure I will need also a spare set of gaskets. Can anyone help? Thanks!

2007 BF50A, standard long shaft, remote control.
Serial: BAZS-3703985

Yes, #17 and you can see the number (3) to indicate it is the bottom carb. You need to use your ENGINE SERIAL NUMBER to get the designated one. I can't tell you exactly where the serial number is located on your outboard but typically I look near the starter and if its not there I start looking at the front of the engine. Usually its not too difficult to find but can be buried behind a harness or some wiring on some engines.

Once you have the serial, it's just a matter of going back to the parts page and matching it up with the "right" #17. Or, hondadude may chime in and just give you the part #...if he's not up to his a++ in alligators at the moment!

I think that tool will work great! But, I didn't see any "valves" in the photo to isolate the carb being adjusted. You may want to get some to go with it if they are not included. Otherwise, a pair of medical hemostats will work if you can't find anything else.

You're right, the carbs aren't all that expensive but I guarantee that the screw will come out with dental picks and holding your tongue "just so". The secret is to get it turning CCW and then turn it until you think it should be free of the threads.....THEN TURN IT ABOUT 40 MORE TIMES! It just seems like those screws have a TON of threads. The screw will NOT just pop right out after the threads have been disengaged even thought it has a spring pushing against it.

The little oring that seals the passage will be holding it in there with a sort of "rubbery tension" and it is always necessary to work one of the picks up under the flat "head" and then pull out while turning with the other one.
YOU CAN DO IT!

Also, I wanted to tell you that the bottom carb is the BASE or "reference" carb for your synchronizing efforts. You get the bottom carb close to perfect then move to the middle and then the top. After "matching" the two upper carbs to the bottom one, go back and check the bottom because it may have changed a bit. If it does, you dial it in again and then go back and match the other two to it. Might take a few attempts to get it BANG on.

I'm sure all this is in the manual but I thought I would mention it.

The part number for the carb will depend on the etched in numbers on the top of the carburetor.....like BG31CD. Let us know what number is on it and we can lead you to the correct carburetor.

Mike

Ah OK. I will be away from the engine for the next few weeks.

Is it possible for me to look up the exact carb by my (stamped on plate on bracket where connects to transom) serial number BAZS-3703985?

I can try to call honda directly and see what they get me for a part #.

I doubt that they can give you the part number....they will need to know the carb # also.

Mike

I wouldn't buck Mike's advise on this one neversummer...HE KNOWS... and he wouldn't steer you wrong. Like I said before, the bottom carb is the BASE or reference carb for the others so you will absolutely want to order the right one for a perfect match and not introduce any 'variables" into an already confusing situation.

Hi jgmo,

A quick clarification. You wrote:

jgmo said:

You can get that idle screw out. It just takes a couple of dental picks stuck in to the flat surface of the screw that you can see and then "manipulated" in a counter clockwise direction. New screw kit will come with screw, oring and new limiter cap. It needs to be done so that you can check for proper carb sync.

Click to expand...

jgmo said:

To confirm, when I get my sync gauge and try to sync the carbs, I am supposed to be adjusting the idle SPEED screw on carbs #1+2 to make them match carb #3. NOT the idle MIXTURE screw. Correct? Because the idle mixture screws have the limiter caps, I am assuming they have never been messed with, and so I should leave them alone.

Another test I tried --- I took an empty bottle of lower unit gear oil (with the nozzle), cleaned it out well and filled it with fresh gas. Then I connected this bottle to the rubber carb drain tube coming off of the #3 carb to attempt to backflush the carbs --- that is, I opened the carb drain screw, inverted the bottle, and lightly squeezed, forcing gas into the carb. Looking down all 3 carb throats I could see gas flowing up into the carb throats of carbs 1+2 quite readily but more slowly out of carb #3 (bottom carb). I am wondering if this is telling me that there is still a passage plugged in carb #3, potentially the passage under the idle MIXTURE screw which I have been unable to access?

Best,

Ted

Click to expand...

Question 1: Yes, you typically set the idle mixture to "factory" or specified turns out and then sync the carb using the set screws on #1 and #2 to MATCH #3. Honda calls em set screws you call them "idle speed" screws.
But ....question two may need to be addressed BEFORE any syncing takes place.

Question 2: That IS interesting. I doubt that the idle passage has anything to do with what you are seeing....a discrepancy in the amount of fuel you can force up out of the float chambers...but then I have never done that or know of anyone doing it so I really don't know. You would think that all three would be the same so...it's DEFINITELY something to consider....

Go back and read your comments on post #8 of this thread....about blockage of some sort. I agreed with you then and I agree now. I (along with you) am not convinced the carbs were all cleaned properly at the first dealer and the second dealer never got a shot at doing it because it "fixed itself" on the trip over there. Another indication of something causing a blockage.

That may also explain why the throttle plate in carb three is at such a different angle from 1 and 2. Maybe the guy at the first dealer ran into a problem syncing or getting the engine to run smoothly and had to "fiddle" it.

I LOVE trying to sort out these types of problems and would sure like to take a crack at it IF I were close enough and IF I had the time. Unfortunately, NEITHER is true.

I think we got it Jgmo!

I got that MotionPro carb synch tool. I calibrated it, and hooked it up. My carbs were sure enough NOT in sync. See photo for the differences in vacuum.

Adjusted the top two idle screws and it evened waaaay out -- I got all 3 lines to be nearly identically equal --- so far so good, no more shaking! Very easy procedure to do, and I definitely recommend this tool.

Fingers crossed that this is a permanent solution -- can't thank you enough.

https://www.dropbox.com/sc/xorlcuxrot5wtnz/AABavqFS0GlaTeeqqCOqI849a

Well, this is where I say "AW SHUCKS, IT TWARN'T NUTHIN'" and that would be accurate. I didn't do much of anything. YOU made the decision to buy the tool and YOU did the work. I am but a CHEERLEADER I'm afraid. But, sometimes, that's what we need...somebody cheering us on and.....cheering us UP. YOU cheered me UP this morning!

I do have a question though. Did you notice if, after the sync up was done, the throttle plate for #3 was any closer to being at the same angle as 1 & 2?

Since I don't get to do much of this, I am curious as to how that might look for future reference.

Fingers Xed!