2007 15HP (BF15DK0) Trouble

Hi folks. Have a 2007 15HP on an RIB inflatable that has been sitting for 4 years. Fuel had been drained, fogged, oil changed. Will fire/run for a second or two (but only with the choke partly open, then die. Was able to get it started finally by giving it throttle right away, pushed the RIB with it. Could not get it to full RPM/power, and it would die at idle.

Removed carburetor today and disassembled/cleaned/lightly blew out with compressed air. I do not fully understand the operation of all the carb bits, but I followed the shop manual. The old fuel remnants had dried to a varnish, it was pretty messy in there. Put it all back together and it will fire/run for a second or two consistently now, but I could not get it to run at all. When I try to give it throttle when it fires/runs, it bogs down and dies. Worse than before somehow.

Would really appreciate any help/thoughts. Pretty frustrated.

Thanks.

There are a lot of passages just in the float bowl of this carburetor. It also has an accelerator pump, which is probably stuck.

If it is as bad as it sounds, you will probably have to buy at least a new bowl #5 and accelerator plunger # 14 set http://www.boats.net/parts/search/Honda/Outboard%20Engine/2007%20and%20Later/BF15DK0%20LHA%20/CARBURETOR%20%28MANUAL%29/parts.html.

Then you still have the upper parts of the carb to clean out....which control the idling.

Bottom line....if you are not knowledgeable of carbs and do not have plenty of time for a learning curve, you might be better off, just buying a whole new carburetor #10. Stick it on and go boating.

If you have the time, patience and want to spend the time on it, several of us will help you through it. You can check some of the other posts on cleaning carbs or carb issues.

Mike

Hi kabennett.

Welcome aboard the Forum!

What Mike said. Your carb can be cleaned and brought back for proper (excellent) performance but you should prepare yourself for a bit of a "journey". It boils down to either:

A... taking it off, improperly cleaning it, putting it back on and experiencing the disappointment of it not working. You just went through round one of what is usually a 10 or 12 round fight. Or 16 or 20...it varies.

B....having us walk you through it but you don't get it right for several reasons. One is that we are doing instructional over computers and the back and forth is MORE THAN confusing. To a large degree the other is that most guys don't take direction all that well and go off on tangents where they "think" they've "got it" but skip a critical step and provide no feedback so we don't know...now, EVERYBODY'S frustrated. This is a better option than A but is still usually a 5 to 7 round bout of "take it off, put it back on, try it, it don't work, yadda yadda yadda.

C. Buy a new carb and bolt it on and go. For under $150, including shipping, you're back in business. The simplest of all the options but not necessarily the best, in my opinion. Why you ask? Because you don't learn anything! Now, you have two of the little buggers and, eventually, the new one is going to get dirty and need service and you're right back to square one.

D. Purchase the Honda Carburetion Manual For around $50, including shipping, and clean it right the first time. Not only that, but truly learn a good deal about carburetors and their "secrets" as you do so. The manual isn't perfect and you may still need a bit of guidance (especially with that accelerator pump circuit Mike mentioned) but it will almost guarantee that you will get it fixed in the first one or two tries.

In addition, your outboard has another item that may need attention. If it doesn't now, it will soon. Item #2 on the page linked below is housed inside item #3 that is attached to the engine oil dipstick tube. This "fuel chamber" collects water and needs to be periodically taken off and emptied out. If this is not done once in a while, especially before storage, even a new carburetor will not perform correctly.

http://www.boats.net/parts/search/H... and Later/BF15DK0 LHTA /FUEL PUMP/parts.html

That is as honest an assessment of where you are as I can give. The ideal path, if you have the money, is to buy the manual and follow it through. That way, you will have it and the knowledge to do it again at a later date. Because, with these little carbs, they need to be cleaned out and serviced from time to time.

Thanks guys, much appreciated. Since I've already done option A, I think I'll go ahead with options B, C, and D. Having a spare carb wouldn't be a bad thing. Have ordered a new one from the link above. Will also order the carb manual. Without the rush of needing to get the old one working, patience will be a bit easier.

Where to start with cleaning the old one? I took everything apart per the Honda service manual. There was a bit of crusted, varnish-like and corrosion-like gunk, and I could see where the float had been stuck to the bowl. I cleaned everything with carb cleaner and tried to blow out all passages with compressed air. The passages through the bottom of the bowl passed air to varying degrees, and all passed carb cleaner fluid. I know there is a lot I'm missing. Can you walk me through it?

Well, here's what you won't find at all in the Honda shop manual and will find very little of in the Carb manual:

This PARTICULAR little carb will NOT work at all if the ACCELERATOR PUMP circuit is plugged! The circuit was intended to give a SHOT of extra fuel during hard acceleration to keep the engine from hesitating. It consists of the plunger, plunger bellows (dust boot), piston and spring components in a cylinder. All that is activated by a plastic arm attached to the throttle plate linkage. Below the piston, in the between the float chamber and the piston's cylinder is a little stainless steel check ball that allows the cylinder to receive fuel and re-charge the cavity anytime it is emptied.

NOW, GET THIS!! You can take all that stuff...piston...plunger...spring and check ball and throw them in the trash and the ENGINE WILL RUN JUST FINE!

WHY? Well, for the most part, it is because this is not a very effective or useful version of an accelerator pump! It makes VERY LITTLE difference whether it is in perfect operating condition or if all those components are missing. Most guys would not detect that anything was wrong if those parts were not present. Only a very slight "hiccup" with a hard twist of the throttle.

What it IS good for though is SCREWING UP the operation of this carburetor! That's because, apparently, this carb needs to vent itself, somewhat, through the circuit that the accelerator piston FEEDS in the main body.

Once you have the float chamber off and the pump components removed, you can find the little hole that the piston forces fuel into as it is pushed down and then find the associated hole in the main body. That is the ENTRANCE to the passage for the accelerator TUBE and it's orifice.

The tube is at the entrance to the VENTURI (throat) of the carb. It is brass and juts out into the incoming air stream from the side.

In MOST CASES, on a carb that is not functioning properly, you will find this tube and the passage plugged up tight. It can be a tedious job to get it unplugged. I have spent upwards of two hours getting carb spray to flow reliably through that tube.

You have to put the spray straw into the feed end and, if it pressurizes, the passage is plugged tight. You then need to prop the throttle plate open and go into the Venturi from the back of the carb and locate the ORIFICE near the tip of that tube where the fuel needs to come out. You take the carb spray straw and carefully place it up against the ORIFICE so that you can try and force cleaner BACKWARDS through that passage. If it will not flow, you then need to go back to the entrance and try there again. Then it becomes a "back and forth" like that until what ever is in there breaks loose.

Then, YOU ARE STILL NOT DONE! You need to keep doing this until you can force carb spray through the entrance of the passage and, with the throttle plate always propped in the fully opened position, carb cleaner SHOOTS from that brass tube and out the back of the carb throat on the order of 6 FEET or more. That's right! 6 FEET out the back! When you get it to do that, the passage has been reliably cleaned.

What I have just told you is BIG TIME toward the proper cleaning of this little "gem" of a carburetor. I paid DEARLY to learn the above and you are getting it for being a member of the forum. Don't DEVIATE from getting that passage as clean as I indicated and you WILL be successful in making your now "spare" a fully functional part again. There are a few other tips that I can provide you but that is all I have time for now.

Good luck and happy boating.

jgmo said:

In MOST CASES, on a carb that is not functioning properly, you will find this tube and the passage plugged up tight. It can be a tedious job to get it unplugged. I have spent upwards of two hours getting carb spray to flow reliably through that tube.

Click to expand...

That's exactly what I found yesterday. The rest of the accelerator pump seems fine, but that passage was plugged. It seemed to pass an extremely minimal amount of air. Not knowing what you just told me, I assumed this may be normal, and after all, why would a plugged accelerator pump keep it from starting....

On that note, do you suspect anything on the low-speed/idle side given the difficulty starting/idling?

I will give what you describe a go and see if I can clear it. Many, many thanks for your help. You really know your stuff.