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can bf50 float bowl be removed without removing all of the carbs?

S

swade

Contributing Member
I have this honda bf50 I was going to use on my pontoon before i sold it for this deckboat with the 130. Don't know anything about it hardly, have only seen it run and it's been sitting about 6 months now i need to sell it since i'm not going to use it.

It's flooding out the carbs in the airbox I think as I noticed the air box drain tube was leaking. I removed the airbox cover and a lot of gas came out, i can pump the primer bulb and when it gets stiff gas leaks out of *all 3* carbs. I'm assuming this isn't normal? And since it's all 3 and this is supposedly a low hour motor that there's some trash in the float seat or worn needle valve there or float adjustment? or could it be something worn on all 3 carbs (seems remote) they seem to leak at the same rate. Does it sound like I'm on the right track? Seeing as I can't start it, seems like it's flooding from that. Sorry i know nill about carbs except the basics.

Thanks!
 
looking at the manual and how little space there is to remove those bowl screws...seems pulling the carb would be easier i guess looks pretty simple, linkage then the long bolts.
 
If you look closely, the manual says to take the carbs off as an assembly with the intake manifold, where the intake manifold bolts onto the head.

Most likely, your floats are stuck open from gooed up fuel.

Follow the manual and you should be fine.

Mike
 
thanks, mike, I'm going to read that section tonight more closely.

i got it to startup, (might have been choking it wrong, not used to those). Running rough like it's missing on a cylinder and won't stay running. pretty sure a cylinder isn't firing. Going to go back and check the basic stuff tomorrow, 1 might not be firing due to the plugs. We ran it dry when i picked it up many months ago. That said that it leaks past when i pump it up seems odd, and the plugs look like it's been running pretty rich (black). Not sure how much fuel care it had had before I bought it, so i'll check the basics tomorrow then decide if i need to clean all the carbs, does seems like stuck floats somewhere that you can pump it up and leak past the needles.
 
Well heh now i'm not sure.

I put fresh plugs, runs a little better, starts up everytime but run *really* rough and won't stay running. I can't tell if it's starving for fuel or getting too much.

* Getting a spitting noise out on of the carbs every so often *seems* the one with the most fuel drip when i keep priming the bulb but not sure.
* runs rough with choke off, on it dies
* Looks to be running rich? getting some black soot coming out the exhaust onto the prop and lower unit.

seems those are too much fuel symptoms, like you said maybe it's gummed up or something.

I need to do a compression test but have to get the right size adaptor for my gauge for these small plugs. I'm thinking it's ok oil looks good, plugs looked good and alike, just black.

So i guess next I'll read this section of the manual and figure out what gaskets i need if i pull this off to clean everything.
 
It is good that you are going to do a compression test before you get into the carbs...

You will need intake manifold gasket, carb base gaskets, o ring set, possibly the muffler plate gasket (if it rips).

Since you are probably having an issue with the float valves sticking, I would replace those also. I usually also replace the the jet set (long skinney tube going up through the carburator)....it is impossible to assure that you have thoroughly cleaned them and sometimes they develop very small cracks around the base of the tube especially if the motor has any time on it.

Mike
 
yeah i ordered the 12mm compression adaptor i don't have, will see, will probably make the carbs a winter project. Hoping it's just the carbs, kinda picked this motor up cheap in a hurry by gut feeling when i was rushing to find a motor for the pontoon before the end of summer. Gut usually isn't wrong but sometimes it is =) i'm thinking it's just that, 03 that looks like it's had very little use, but can't say i was smart enough at the time to test it well before i bought it. Will check the basics more first.
 
Finally got the 12mm adaptor and compression is right on spec. So guess it's time to do the carbs and see if that makes this run. Thanks for the parts list info!
 
I finally got around to getting this apart, that top carb that was leaking so much when i pumped up the fuel bulb and was leaking when it was running rough has a good bit of grit in it (fuel filter is really dirty looking), probably keeping the float from seating fully i imagine, sure the other 2 has a bit there as well.

How do you remove the that long skinny jet set (the one through the carb)? It doesn't say in the manual but it looks from the picture that it simply unscrews? or will it pull out if i jerk it, couldn't tell so didn't want to try.

thanks!
 
Do not pull it out...you will probably deform it.

Look inside the intake of the carb...open the butterfly and you will see the other end of the tube. There is a little protrusion near the end of the tube.

Take a small standard blade screwdriver and put it under the little ledge inside the carb and gently twist the screwdriver to pry it out. If you can not get to it easily from one end, try from the other end.

I hope that makes sense.

Once it is out, check the tube for very small cracks with a magnifying glass. These are very hard to clean. Most of the time, i just replace them to be safe.

Mike
 
Hi mike thanks, I see what you're talking about, will do, yeah i'm going to replace what you mentioned while i have it apart.
 
Hi!

Got it back together, i replaced the gaskets, jet sets, I didn't change the needle valves I couldn't see any noticeable wear. Float heights were pretty much .5 in across the 3. Cranked *right* up without any of the previous problems! Only thing is it's idling pretty high. i don't see any vac hoses i missed. Manual says to sync the carbs if the idle is high after adjusting the idle stop, it's not even hitting the idle stop screw so adjusting that seems pointless, it's nothing i goofed up with the linkage it's resting at bottom.

So I guess i should sync them next, does that sound normal after a cleaning? or could i have missed something? (though seemed simple enough procedure) I only had time to run it about 15m tonight.
 
Figured out the high idle, I had tweaked that bottom carb linkage at some point just enough to stop on the case, which is why it was idling high!
 
Ok so i got back to working on this bf50. A lot better after the carb rebuild and that linkage tweak, but it has a slight miss and puffs out a bit of smoke during the miss...something isn't right.

Quick review:
---
I picked up a carb synchronizer (gauges) and got the 3 close (it's an 03, no hoses to pinch off). But I've got this darn miss and seems to idle a bit rough. As mentioned I pulled the carbs apart (twice) cleaned them, replaced all of the gaskets and main tubes, the only thing I didn't replace was the needle valves as they looked fine to me. It all seems tight and is no longer leaking fuel out the carbs when the bulb is pumped tight.

During carb sync the gauges seemed to show a bit low vacuum, if i'm reading these right about 10lbs at idle. i've sprayed oil around carb, hoses don't see any vacuum leaks, also make sure everything was tight. New plugs, compression is perfect factory specs using the manual. I was starting to wonder about the timing.
---

I decided to pull the timing cover, with the cam pulley T aligned with the T there, the T on the flywheel is 2 flywheel notches left of the mark on the hanger bracket. (when looking from the electronics side of the engine, not carb side). So I'm thinking this is my problem correct? it should be lined up when the cam T lines up with that T?

I'm reading the manual on timing adjustment now it's a bit confusing, is there an easy way to do this?
 
Well ignore that, it's tough to tell. If i rotate it counter clockwise at the cam T that's definently around tdc, and the flywheel pulley sometimes seems a notch or so behind, sometimes right on. I'm betting it's ok there and my problem lies in a vacuum leak or the carb still. The slight miss is consistent through the throttle range also, you can tell as you get a puff out the exhaust. Plugs are new but i'll double check the gap. still suspect the carb i guess.
 
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Yep...probably something in the carbs. Make sure idle mixture screws are adjusted. May have to back out a little more.

Mike
 
The idle mixture screws have the tabs which prevent adjustment so I assume nothing to do there? I'll pull the carbs 1 more time before i call myself beat on this one =)
 
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