Honda BF50A Cylinder Dead

[kingtoros]

So I hope you all got your pizza, had one guy working the past few months delivering around the globe. He took a bunch of cash and I got a slice, but he promised it would be delivered to everyone active on the board this year. Not my fault for failure to deliver!

This next one may be on me for not looking under the cowling closely at my engine before buying this 2005 26M . I had trouble with the 2005 Honda BF50A. From a warm cycle it wouldn't go WOT without stalling, and max RPM was 4k... I took it to Philadelphia Boat and the mechanic there put the engine through its paces. He identified the #2 (of 3) carb was damaged and basically I had a dead cylinder. The damage being attempted to be repaired with some sort of putty by one of the previous owners...

They advised the part is NLA (no longer available) from Honda and they didn't want to risk putting in a used or ebayed part. Kudos to them for being upfront and after talking a bit reassured me that if I found a carb, based on my level of experience, I should have no problem swapping it in. They even got me the exact part number and sent me on my way for a nominal (and reasonable) diagnostic fee.

Well, fast forward a couple days and I have found the full manifold may be available. Which has all three carbs and linkages, intake, exhaust, etc... So here's my question to you:

What would you do?

1. Swap the engine, for $4-7k boat gets a pretty new purrrr
2. Run as is, you may not get more than 8knots but hey, it's a sailboat too!
3. Get the manifold and swap it in, it's only $800 and a day of your time to restore the motor for another ten+ years of service.
4. Sell the boat, clearly you got a lemon and the pristine condition of the hull and everything else, well cut bait mate!
5. Start dialing every marine motor junk shop and see who has this motor and will sell you the carb for hopefully no more than it was new ($200)
6. Bring out the flippers, dive in and attach yourself to the transom, when you get her to plane, you've made it.
7. Something I haven't thought of?

Thanks in advance,
Toros

[Russ]

First, thanks for the pizza. A little cold arriving, but yummy.

If it were me, I'd go #3 and get to know the boat more. If after a year, the motor just doesn't work out, go with #1 and hopefully, inventory will be higher. Good luck now finding a new motor.

Use the boat a bit to get familiar with it, the strengths and weaknesses. See where you might better drop some boat bucks.

I'm curious about the PO repair. Putty? So the thing was leaking? What is that about?
Before dropping $800, I might pull that apart and see what's going on. I'm not familiar with that motor, but perhaps it can be rebuilt for less. Do they sell a rebuild kit?

[Be Free]

#3. When you remove the carbs on that engine you take them out together by removing the manifold with all of them still attached. Get a set of gaskets and a rebuild kit for all three carbs. The jets may be clogged but they are unlikely to be damaged. Replace everything that comes in the rebuild kit. FYI: the carbs for a BF40 will not fit a BF50. The BF50 has an additional jet.

[adudinsk]

Carb ?Damaged?
1) rebuild it.. replace jets.. $100.. maybe...
unless someone hit it with a hammer... and cracked it.

Could be a bad float..
(thats also in the rebuild kit.)
Carbs should be easily found for Honda....

Avoid aftermarket Chinese ones..

Also what does "dead cylinder mean"
Black death (hole in piston)
Low compression.. (blow by.. values?)
or no fuel from the carb..
Also many carbs have an INTERNAL little tiny fuel filter.. (part of rebuild kit)

[adudinsk]

Also if you have more than one carb.. they must be synced..
This will make you run MUCH better... no bogging.. better fuel economy.
You put a set of gauges (about $100 or so) on all the carbs (they have a special port for this) and set it to an RPM as indicated by the service manual
Adjust the vacuum so they are all the same on each carb .. easy to do with the correct tool..
Makes a HUGE difference..

AD
Anyone with a car'ed motorcycle will know EXACTALLY what I am talking about.

[Tomfoolery]

Anyone with a car'ed motorcycle will know EXACTALLY what I am talking about.

Sure do. But you can build your own if you don't want to spend the money by looping small clear nylon tube on a board and filling with water so they're all reading the same with no vacuum applied. Takes a bit of fiddling, though.

Edit: I see that mechanical gauges dominate now. And they're easier to use and store. And they're cheaper in sets of four. So ignore the above since it shows how far removed from this stuff I've become. Time is now measured in decades rather than years.

[chipveres]

#3 again. $800 is a bargain to save a $5000 engine.
Chip V.

[Tomfoolery]

#3 again. $800 is a bargain to save a $5000 engine.

I'm not sure what I'd do, but #3 has the advantage is leaving the OP with two spare carbs. I've never had a carb problem, but I've seen enough discussion about those Honda carbs being clogged and needing rebuilding (not always successfully) that ending up with spare carbs on the shelf is not a bad idea. And he could always sell them later, since they're hard to find apparently, and which would obviously offset the cost of the manifold.

[adudinsk]

Ahh.,.. yes.. water filled tube..
Or.. the mercury gauges...
I just bought a 4 pack of gauges.. typically used for motorcycles..
Worked fine.. (got 4 carbs..)
you do have to adjust them so the needles do not pulse.. (a valve..)
Ideally you would tune the carbs to the RPM that you normally cruise at.. (2500 ... 3000 etc).. so your sweet spot is at exactly that rom that your mostly running at.

I just set mine like the manual.. they suggested 1500rpm..

I enclosed the exact set I got.. (paid $100 this summer).. prices vary all over the place.

[adudinsk]

My initial probs were plugged jets.. that caused a no start
I then ran into surging...
This was due to a poorly adjusted float.
Easy fix..
Sync'ed the carbs..
Runs rock solid.. HUGE difference.
It was initially daunting on how to pull the carbs.. as it was a lot of "things" you removed... disconnected..etc.
Needed thin walled socket...
(ground down a standard one... no biggie)
But now.. I will pull/clean in one afternoon.. easy.

I would say that its a GREAT learning experience to rebuild carbs yourself..
you will need to do this every so often..
and you will pay through the nose if you have to hire it out.
(and also.. get a good torque wrench.. and torque everything correctly and in the correct order if stated)


AD

[Be Free]

Anyone with a car'ed motorcycle will know EXACTALLY what I am talking about.

Sure do. But you can build your own if you don't want to spend the money by looping small clear nylon tube on a board and filling with water so they're all reading the same with no vacuum applied. Takes a bit of fiddling, though.

Edit: I see that mechanical gauges dominate now. And they're easier to use and store. And they're cheaper in sets of four. So ignore the above since it shows how far removed from this stuff I've become. Time is now measured in decades rather than years.

When I built mine I used transmission fluid in the tubes. It is colored and a little thicker so it "absorbs" some of the jiggle.

I can tell you from experience that if the carbs are not synchronized the engine will not run correctly. If you don't find it online post here and I'll drag out my old Honda manual and give you the proper sequence (or Tom can probably tell you from memory )

[opie]

Can we get closeup pictures of the carb damage?

[NiceAft]

Does this help at all? From the Honda manual.




In the lower right, the drawing is for the carburetor synch adjusting screws for 25-50 models.

[kingtoros]

Also what does "dead cylinder mean"
Black death (hole in piston)
Low compression.. (blow by.. values?)
or no fuel from the carb..

The shop mechanic confirmed spark, fuel and good compression on all cylinders. What he meant (and what I meant) was that the damage to the carb is such that the cylinder isn't firing. So, basically running on 2 out of 3 cylinders.

Can we get closeup pictures of the carb damage?

Yes, the boat is in a storage facility nearby, I'll drive out tomorrow afternoon and snap a few photos.

Does this help at all? From the Honda manual.

Yes, I have a few of these manuals from the original owner of this boat, but this still helps direct what I'm looking for.
---
I have a follow-up question How do you guys source your rebuild kits? Looking at the exploded diagrams of the carbs and the manifold, it looks like the position, orientation and size of the different components are very specific...
---

It sounds like the overwhelming response is to (3) get the manifold and (7) rebuild the carb after it's pulled (or just attempt the rebuild if it's not damaged like the shop mechanic described). I think you guys are right and this is the way to go. After I confirm the serial # on the engine, and the part #s on it, I'll place the order and keep you guys posted. It's approaching winter here in Philly and this will probably be a spring project. Will likely source the part and stow it for the spring.

Lastly, for reference ... this is the part # of the damaged carb: 16102-ZW4-F02
And this is the manifold part #: 16100-ZW4-F05ZA

I used the Honda Marine site to find the assembly part #: https://peparts.honda.com/marine#/brows ... F50A5-SRJA

[adudinsk]

If the carb is damaged.. you would not get fuel.
The mech said you had fuel/compression and spark.
This means the cylinder is fine.
I bet you have either a plugged jet in the carb.. (not enough fuel... )
or a misaligned float.. that is cutting off the fuel almost instantly. (super easy fix)

Unless the carb body is cracked.. it should be rebuildable.

Some have a SEALED jet.. for EPA... (mine did) and they say its not adjustable. For emissions..etc

Those can plug up.. and they are "sealed".. so the "carb is useless"
But....
what you do is take a TINY hand drill.. or a dremel tool. and drill a hole in the cap covering the "sealed" jet
then use a pick (I used a cork screw)... and pull the cap out.
Then you can remove/clean and adjust the jet ..
Maybe that is what is the trouble.. a plugged jet that is factory sealed?