Logo
FULL SITE MENU

BF20D Honda Outboard, trouble starting and idling

S

SJWPortland

New member
Hi everyone, new to the forum.
I have a 2010 Honda BF20D manual start outboard that will only start with a quick squirt of starter fluid and once started will not idle until warmed up i.e. feathering the throttle for around 5 minutes. Once warm it will stop and start no problem but if I attempt to start 24hrs later I have to follow the same routine. Read many posts, scoured YouTube and poured $$'s into the outboard without success.
Having not been used for several months and unable to start I did a full service (fluids, filters, spark plugs, impeller, etc) and got her working, then every couple of weeks I would start her up without problems until around a month ago when she refused to start. Cutting a long story short I have since put on a brand new carb, new fuel tank and fuel hose. After installing the new carb she started up but some two weeks later she would not start again. After pulling the drain on the carb I noticed water in the fuel which led me to change the fuel tank and hose, I primed the system using fresh fuel and removed any remaining water from the lines. I eventually got her started and took the boat out for around 2-3 hrs without issues starting or idling but 24hrs later and same old story. It's at this point that the engine will start with a squirt of starter fluid and not idle until warm.
I'm handy but this is my first outboard, incredibly frustrated at this point, appreciate any genuine help.
 
Hi,

Sorry you're having problems. I have a 20D and have worked on many of them. They are typically very reliable, rugged outboards but I know this must really be frustrating.

Ok,now to see if we can get her straightened out. First off just a couple of questions:

Did you closely inspect the choke cable and starter valve set when you replaced the carb? See items 12 and 20 in the link below.

This carburetor doesn't use a conventional "butterfly" choke so the starter enrichment valve is the cold start mechanism. The valve, along with the choke cable, I have found to be problematic on these after a few years of service. If the connection between the cable and the valve becomes loose or comprised then hard cold starts are bound to occur. Also, the valve screws into the carb body with crappy, weak plastic threads. Over time and because of engine vibration those threads can wear and cause the valve to become loose. This will adversely affect the amount of enrichment for cold start. Those threads are also easily damaged by just the slightest over tightening. You should look for any deterioration or cracking/splitting where the cable enters the valve boot. Manipulate the cable in and out while observing for movement of the valve or swelling of the curved boot. If you see either taking place,I would recommend replacing both the cable and the valve at the same time. Although it might seem that the cable can be reused with a new valve, I can tell you that my experience is that it's not a winning strategy. I tried it and subsequently determined that replacing them both together is the way to go.

https://www.boats.net/catalog/honda.../bf20dk3-lha-2007-and-later/carburetor-manual

When was the last time you emptied the fuel chamber? See item 3 in the parts page link below.

https://www.boats.net/catalog/honda...ge/20hp/bf20dk3-shta-2007-and-later/fuel-pump

The fuel chamber will act as a water separator and needs to be emptied out periodically or it will collect water and feed it to your carburetor. The minerals in that water will "plate out" in the carburetor passages and cause problems.

You need to remove the fuel chamber from the engine to completely empty it. It's easy to take off but it is held by a shock suspension holder mounted to the engine oil dipstick tube. See item 4 in the link. It's important to take care to not damage the dipstick tube when sliding the holder and chamber off. If you spray a little WD-40 on the tube, the process is much easier. Just pull the the two fuel lines off of the chamber, spray the tube and carefully slide the contraption off the tube. Shake the chamber out dry.and reinstall just keeping in mind that bending or breaking the oil dipstick tube would be bad ju-ju.

I really hope that your use of starter fluid (ether) can end soon as it can be very damaging to an engine. I always recommend using propane as an artificial enrichment for testing but I realize that it is slightly more complicated and most people don't want to learn how to do it. However, it will NOT damage your engine and is actually safer for YOU than any "liquid" used for doing so.
 
Last edited:
Thank you for such a detailed explanation jgmo as well as the links to the parts diagrams.
On the carb., the new one came with the Starter Valve Set (item 12) and I had purchased a new choke cable (item 20) as part of the rebuild so everything is new in regards to those parts. I won't lie I was a bit stumped to how the choke worked as I was used to a butterfly style choke. The choke cable itself has a movement of about 0.75" from open to close.
When you say "If the connection between the cable and the valve becomes loose" are you talking about valve (item 12) and cable choke (item 20)? I assume that's what we are talking about.

https://www.boats.net/catalog/honda/...buretor-manual

The fuel chamber I have never touched so this will be the next action, not an easy feat as the oil dipstick tube has rust along it's length but I'll do my best to work it free.

Trust me I'd much prefer not to use the starter fluid and do use sparingly but obviously not the long term fix :)
Again thank you for your help, I'll be sure to keep the post updated with progress.
 
Hi,

Yes, I was referring to the connection of the choke cable (20) to the valve mechanism (12). The cold start enrichment (choking) will be reduced by any undue "play" because the valve will not be moved upward off it's "seat" enough.

But if you have a new cable and valve installed that shouldn't be the issue.

I guess we'll wait and see what happens after the fuel chamber is emptied. I have had a few 20D outboards suffer starting problems with water in that chamber.

Just to add to my warning about the use of starting fluid....
The reason it's not good is because it doesn't ignite and then cause a flame to rapidly advance and build pressure, it EXPLODES instead. These explosions make it a reliable "fire starter" but also affect the engine much like pre-ignition or a condition known as....relatedly....DETONATION.

The explosion sets up stresses in the combustion chamber that can and do chip valves, break piston rings and remove metal particles from the piston crown and cylinder head. This typically "small" amount of damage becomes accumulative over time and will eventually damage an engine enough that it becomes what is called "an ether baby". Meaning that it won't cold start at all without using the fluid. That's why it concerns me.

I would use ether to start an engine in a dire emergency only. But...to each his own. I won't mention it again here. Soap box back in closet.

Good luck
 
Last edited:
jgmo said:
Hi,

Sorry you're having problems. I have a 20D and have worked on many of them. They are typically very reliable, rugged outboards but I know this must really be frustrating.

Ok,now to see if we can get her straightened out. First off just a couple of questions:

Did you closely inspect the choke cable and starter valve set when you replaced the carb? See items 12 and 20 in the link below.

This carburetor doesn't use a conventional "butterfly" choke so the starter enrichment valve is the cold start mechanism. The valve, along with the choke cable, I have found to be problematic on these after a few years of service. If the connection between the cable and the valve becomes loose or comprised then hard cold starts are bound to occur. Also, the valve screws into the carb body with crappy, weak plastic threads. Over time and because of engine vibration those threads can wear and cause the valve to become loose. This will adversely affect the amount of enrichment for cold start. Those threads are also easily damaged by just the slightest over tightening. You should look for any deterioration or cracking/splitting where the cable enters the valve boot. Manipulate the cable in and out while observing for movement of the valve or swelling of the curved boot. If you see either taking place,I would recommend replacing both the cable and the valve at the same time. Although it might seem that the cable can be reused with a new valve, I can tell you that my experience is that it's not a winning strategy. I tried it and subsequently determined that replacing them both together is the way to go.

https://www.boats.net/catalog/honda.../bf20dk3-lha-2007-and-later/carburetor-manual

When was the last time you emptied the fuel chamber? See item 3 in the parts page link below.

https://www.boats.net/catalog/honda...ge/20hp/bf20dk3-shta-2007-and-later/fuel-pump

The fuel chamber will act as a water separator and needs to be emptied out periodically or it will collect water and feed it to your carburetor. The minerals in that water will "plate out" in the carburetor passages and cause problems.

You need to remove the fuel chamber from the engine to completely empty it. It's easy to take off but it is held by a shock suspension holder mounted to the engine oil dipstick tube. See item 4 in the link. It's important to take care to not damage the dipstick tube when sliding the holder and chamber off. If you spray a little WD-40 on the tube, the process is much easier. Just pull the the two fuel lines off of the chamber, spray the tube and carefully slide the contraption off the tube. Shake the chamber out dry.and reinstall just keeping in mind that bending or breaking the oil dipstick tube would be bad ju-ju.

I really hope that your use of starter fluid (ether) can end soon as it can be very damaging to an engine. I always recommend using propane as an artificial enrichment for testing but I realize that it is slightly more complicated and most people don't want to learn how to do it. However, it will NOT damage your engine and is actually safer for YOU than any "liquid" used for doing so.
Click to expand...
Any chance you can post updated links to the parts? I’m having similar issues. Choke doesn’t come out all the way like before. Takes probably 30-40 pulls to get it started. Maybe more. Once it gets hot, it’s fine. Starts up first pull. Carb was cleaned a few times and issues still exist.
 
Ok, here you go...

NOTE;: Do NOT buy the cable (item 20) and try to mate it to your valve (item 12) it just won't work and will leave you frustrated and out the cost of a new cable.

Buy item 12 ONLY since it comes pre-assembled with the cable already installed.


The parts page depiction is misleading because it shows item 12 as being just the valve and cable guide/boot. But the cable DOES come with it as an assembly and makes for a proper repair.

I have TWO QUESTIONS for you;
Have you emptied the fuel chamber? Item 2 in link below.


Question 2.
When you cleaned the carb, did you verify that carb spray from a can would shoot a 6 to 8 foot stream of fluid from the accelerator pump nozzle past the the open throttle plate out the engine end of the carb throat?

It's really an absolute MUST if you want easy starting and maximum performance from that engine.

Welcome to the forum and "Jimmy's 1000 Questions About Carburetor Cleaning" 🤪
 
Just confirming, my engine plate says:
BF20D
BAMJ-1606878

Is that still the correct part? Not sure if it’s universal for all BF20D.

To answer your questions, someone else who works on small outboards in my town is who we hired. So I’m not exactly sure if the fuel chamber was emptied or if the spray can shoot that far. I’ll be picking up the part this week and changing it out. If you can walk me through those two things you suggested, I’ll try them when I’m changing the part.

Thanks again for your help! We’re a bit limited with good outboard mechanics out here in Hawaii.
 
You can attach the file here but if you have problems doing so, I'm not the greatest at explaining how to do that. I think "technology challenged" is the term :unsure:
 
Yes, that is the correct enrichment valve assembly and yes I will try to help you check those things out when you're ready.
 
Thank you so much. I’ll order the part today.

I couldn’t attach videos, it only allowed me to select photos. I uploaded the video to my Dropbox, let me know if you have problems with the link.

Choke Issue Video
 
Well, that looks like the cable housing....the curved section....is probably bad. The cable sort of grinds on it internally and it also simply cracks and gets weak with age. Once the housing gets weak, the cable can kink and then the whole thing just doesn't work.

That's typical of what goes wrong with them so replacing the cable and housing together is the right move.
 
I don't know but it very well could be. If it runs well and makes good power other than at idle, then the enrichment valve is probably the sole villain.
 
Yes, I know it doesn't show it but the valve set does come with the cable pre installed. Which, by the way, is the way you want it since it's practically impossible to mate a new cable to a used valve. Don't ask me how I know:unsure:

It has been a few years since I purchased one but I don't think anything has changed in that regard.

I remember it surprised me the first time I ordered one that it was like that but I was glad it did.
 
Ok, so this is what arrived. Which of these pieces do I need to replace? And which part has the pre-installed cable?

IMG_7915.jpeg
 
Oh man! I am so SORRY!

As soon as I opened this and saw the picture, I just wanted to go hide somewhere!

Clearly I was wrong about the cable coming pre assembled with the guide and boot.
It used to I know because I've ordered several in the past but that's obviously changed.

I think you're only left with the option of buying a new cable or using your old one to install in that guide assembly. I couldn't find another part number for the whole assembly so I don't think it's available anymore.

I know it's a pain but I wouldn't try using the old cable with those new parts.

My sincere apologies for steering you wrong and wasting your time.

It seems that I've simply become of date.
 
Yes, it's not worth taking the chance of using your old cable with the new guide and boot parts because, if that cable is stretched or fatigued in any way, the whole affair will be unusable and you will need to start completely over.

I say that because it's no picnic mating the cable and those "valve set" parts together. That valve set rubber boot is critical to tthe way that set up works and it's very likely that the boot wouldn't fair well if assembled then disassembled and reassembled again.

Very sorry my mistake put your project so far back.
 
Back
Top