BF20D Stalling from Idle

Hello Everyone,

I'm looking for a little help with a 2006 20hp remote control driven outboard I just purchased used. Here's what I can tell you:

- I am following the starting procedure outlined in the manual.
- The gas is 6 weeks old but has been treated with Sta-Bil as per instructions.
- The motor oil and gear oil are new.
- the battery is at least 5 years old.
- the water separating filter and the fuel filter found under the engine cover are both clean and working well.
- I have removed, cleaned, and checked the gap on both spark plugs (they looked clean).

here's the problem:
- the boat starts beautifully and idles well for 10-30 seconds before sputtering a few seconds and stalling.
- After stalling, it needs a few minutes before it will start again (and then stall again).
- if it idles long enough to let me get into gear and up to speed, it runs beautifully for as long as I want to be out until I pull back on the throttle and /or put it in neutral, at which point it sputters and stalls.
- I can't get the primer bulb very firm, no matter how many times I squeeze it.

Any thoughts or advice you may be able to provide would be very helpful. Thank you!

Engine idle RPM is ok ?(it is 900 -+ 50..)after clean the spark plugs,you run the engine for some time again open both the plugs and see what color looks.if it is become black fuel mixture is rich,check pilot screw turns( it is 2 turns out ). check that and adjust idle rpm and try.

if still same problem better to do carburetor service,



wajira

wajira said:

Engine idle RPM is ok ?(it is 900 -+ 50..)after clean the spark plugs,you run the engine for some time again open both the plugs and see what color looks.if it is become black fuel mixture is rich,check pilot screw turns( it is 2 turns out ). check that and adjust idle rpm and try.

if still same problem better to do carburetor service,



wajira

Click to expand...

Thanks, Wajira. I don't have a tachometer. How do I check the RPM? I'll try checking the plugs after running it a bit. Which part would become black if the fuel mixture were rich?

JCS

The bulb not getting firm is a problem. It may be sucking air through a tiny hole on the suction side OR it could have a leak someplace on the outlet side. OR it may have a bad check valve. They go bad quite often.

Make sure that gasoline is not leaking into the oil via the FUEL PUMP. The fuel pump is mounted on top of the cylinder head and if it is leaking, it will deposit gas in the engine oil and, eventually, destroy the engine. So, any signs of gas in oil, take off the VALVE COVER and inspect for leakage while you pump the bulb.

It could be that the carburetor float is not closing all the way. While pumping the bulb, listen for constant fuel movement through the carb float chamber. If you think that the float is stuck, try tapping on the chamber with a screwdriver handle and try again. If you can't get it unstuck, then you may need to service the carb.

The reason it starts and runs initially when cold is that it is on FULL ENRICHMENT. As the enrichment system "backs off", it reverts to the normal idle circuit in the carburetor to get fuel. That is where I suspect that the problem lies. And, THAT usually indicates that the carburetor needs to be removed, disassembled and properly cleaned.
But first, answer this question:

Does this outboard have a "fuel chamber" between the fuel pump and the carburetor? A fuel chamber is a black, cylindrical, rubber looking thing that sits in a black, rubber holder that is attached to the engine oil dipstick tube.

If it has this "device" attached to the dipstick tube, before doing ANYTHING ELSE, remove it, take the hoses off and then shake it and dry out any and all liquid that may be in there. When you are POSITIVE that it is completely empty, put it back on and try running the outboard again. It will either greatly improve or it will remain with the same symptoms. If it still won't idle, then yes, it could be an idle adjustment problem (which I highly doubt) or it is an internally dirty carburetor. If you believe that the idle is too low, you can adjust the linkage idle screw that is on the carburetor near the engine block. Try screwing it in a couple of turns to see if that helps. Don't worry, you can't "screw" this up. That screw does nothing more than hold the throttle open slightly just as if you moved the lever forward a bit at the remote. If it does work to improve your problem it still doesn't mean that the carb is clean. But it might get you limping through the season so that you can use your boat until you have time to clean the carburetor properly.

OK, that was a bunch of stuff...find out what's up with the bulb not getting hard FIRST. Then do the "fuel chamber" shake out SECOND. If it doesn't get better after those two, post again.

Good luck.

Thank you, jgmo. I won't be reunited with the boat for about two weeks. I will try all of the things you have suggested, in the order you specified, and repost if the problem persists.

Thanks,

JCS

Hi JGMO,

Thanks again for your thorough response to my original post. I am headed up to the cabin in the next day or two to work on the boat and I have a few questions:

1. You say "find out what's up with the bulb not getting hard FIRST." How do I go about doing that? Try a whole new fuel line assembly? Hold the hose in water to see if any bubbles come out?
2. Regarding the fuel chamber shakeout: Are you saying I should remove the entire dipstick tube or just the "device" that is attached to the dipstick tube?
3. Regarding the fuel pump: I feel like checking the fuel pump might be above my pay grade as I have no idea where to find it. I don't know where the cylinder head is nor the valve cover so I wouldn't know where to watch for leakage while pumping the primer bulb.
4. Low idle: Someone on another site thought it might be idling below 900 RPM and that I should check that. I don't have a tachometer, so how do I know the RPM at which it's idling? Where is this "linkage idle screw" again?
5. Carburetor float: Where is the chamber for the carburetor float?

I'm a fairly competent guy but I'm brand new at working with outboard motors and I just don't want to screw anything up. Any additional details you can offer would be greatly appreciated.

Cheers,

JCS

Hi Wajira,

Can you tell me how to check the RPM? Also, where is the pilot screw you mentioned and how do I use it to adjust the idle RPM?

JCS

Item, question 1...I could get behind a whole new fuel line...but it's your money. Your other idea of holding it under water is worthwhile too except it won't detect a pinhole leak on the suction side of the hose and would probably fill the bulb with water. A good method for checking a fuel line assembly for leaks is to blow smoke in it and see if any comes out. But, in MOST cases, a line that looks ok usually is ok. If it looks old or cracked or discolored, it might be time for a new one. The primer bulb itself typically goes bad before the fuel line. The bulb has a "check valve" in it that allows fuel to only travel in one direction. When you squeeze the bulb and then release it, the bulb "sucks up" fuel when it re-expands. the fuel fills the void in the bulb and is not allowed to travel back into the tank because of the one way valve. When the line and the carburetor get completely full of fuel, the bulb SHOULD get fairly hard to squeeze. But, if the one way valve in the bulb is leaking, it might never get hard because it is allowing fuel to travel back to the tank.

The one way valve is sometimes built like a "Trap Door". It has a little "flapper" that is hinged on one side and it has a tiny spring in the hinge to keep it closed...much like a kitchen cabinet door. One thing about these types of valves is if they are positioned so that GRAVITY can act on the little door, it can be held open against the weak, tiny spring. Many times you can overcome this problem by keeping the bulb lying in a position where the imprinted "direction of flow arrow" is up, facing you, and not down facing the deck. Some bulbs even have "THIS SIDE UP" lettering molded right in the rubber next to the arrow. You can often find and buy a new bulb in marine hardware stores. You can replace the existing one by cutting the old one out of the fuel line and installing the new one with small hose clamps. Or, you can just purchase a whole new assembly.

Item, question #2...DO NOT remove the dipstick tube!! The "fuel chamber" is mounted ON the tube via a device that SLIDES OVER the tube. Disconnect the fuel lines going to the chamber and simply work it up and off the dipstick tube. Spraying the tube with some WD 40 first can help since it is a tight fit. Refer to items # 2 and 3 in the link below to see what they look like.

http://www.boats.net/parts/search/Honda/Outboard Engine/2005/BF20D5 SRA/FUEL PUMP/parts.html

Item, question #3...If you're not comfortable checking the pump, (item #1 in the link above) then that's ok. BUT...you MUST try and make sure that the pump is not allowing gasoline to get into your engine oil! You do that by simply monitoring the oil level. Probably more frequently than you have been, for a time, until you are sure that the engine is not "making" oil. When the oil level in an engine goes UP instead of DOWN, it's time to stop and find out WHY. If you have taken care of the fuel line and bulb and make sure that is all ok, the line on the "fuel chamber" that we just discussed that... DOES NOT go to the carburetor...goes to the pump. If you left that line off of the chamber and primed the fuel line by squeezing the bulb....fuel will start coming from that line. When fuel comes out of that line while squeezing the bulb, the pump has been primed. If you then pull the starter rope on the engine and you see fuel squirt from that line, the pump is working ok.

Item, question #4...If you don't have a tach, there is NO WAY that I know of to set the RPM other that by EAR. That is, if she's idling and PURRING LIKE A KITTY, is good enough. The linkage idle screw is ON THE CARBURETOR...very near where the THROTTLE CABLE attaches to it. Refer to item #7 in the parts page link below. It has a "Phillips head" and has a small coil spring under it. You can, for testing purposes, turn it it "IN" a turn or so to see if it helps. You won't HURT anything by doing so.

Item, question #5...The carburetor comes in two major sections that are held together with screws. The upper section is the main body. It is bolted to the engine intake manifold and, on it's other side, the air inlet plastic pieces consisting of the air box "muffler" and ducting. The FLOAT CHAMBER is bolted to the bottom of the main body. Refer to item #5 in the link below.

http://www.boats.net/parts/search/Honda/Outboard Engine/2005/BF20D5 SRA/CARBURETOR (AUTO)/parts.html

Don't feel bashful about asking all the questions that you need to. That is why we are here.

hope both the adjusting screws are clear for you but Europe models you cant adjust the pilot screw unless you break the stopper so just see whether you can turn it full round or not.if can tun turn it full in and then turn out it 2 1/8 round .

idle speed only can check by tach meter but hearing the engine sound you can increase the idle after increase it snap the throttle 2,3 time and see, after close the throttle rmp should come down to normal quickly,and at idle you should have smooth gear shifting,that is more important, after adjusting shift gear fwd- rev and see.

first of all follow all the information which given by jgimo ,make sure the fuel lines, old BF20 had recall of fuel line issue but im not sure wht is that for.but that is related to that tank kind of device on the dipstick.

wajira

Just a word of warning...
It's probably NOT a GOOD idea to mess with the idle mixture screw (pilot screw in wajira's illustration). Note that the mixture screw (item #4 in the link below labeled "screw set") is on the OPPOSITE side of the carburetor from the linkage adjustment screw I indicated in my last post. The idle mix screw has a small, plastic cap glued to it to keep anyone from making idle mixture adjustments. If you start trying to turn that screw, it will likely break the head off of the mixture screw and make it MUCH more difficult to remove that screw if, in fact, the carburetor ends up needing a cleaning and rebuild. (which, by the way, I think is HIGHLY probable with the symptoms you've described). Anyway, if the problem does lie behind that screw, all the turning in the world won't correct the issue. So I suggest not "screwing" with it. :~)


http://www.boats.net/parts/search/H...2004/BF20D4 SRTA/CARBURETOR (AUTO)/parts.html

I believe the recall for the fuel chamber was because some of them leaked. If yours isn't leaking, I wouldn't worry about it. But, you could post your FRAME serial number off of your mounting bracket and someone here (hondadude) could check it for you. If the recall hasn't been done then you would need to take it to the dealer to get a new one installed.

i am agree with jgmo not to mess with pilot screw but since its second hand engine maybe somebody already touched it,Europe models cant adjust it but some other models can. just see it for make sure.

And some of the engines i seen, it doesn't have that fuel chamber,maybe it's making some problems,that's why its removed.




wajira