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BF9D rough running under load

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Pat Miller

New member
Hi, I have 9.9 that we bought used I think it's a 2001 or 2002. So here is the facts. Last year the engine ran great. We pull the fuel line and run it dry after flushing fresh water through it ( used in saltwater on a sailboat). This year we tried to use it and found it sputters when put in gear. It seems ok in gear at idle but not when you throttle up.

With the engine not in gear we seem to run smooth but it does not rev up as high as I remember. It almost seems like the engine has a rev limiter on it.

We have replaced the gas, added sea foam, replaced the fuel filter, replaced the fuel pump, removed the carb ( it looked very clean inside) and did a dock side inspection blowing air though the passages. I removed the jets and they were clear. It really seems like a fuel problem, but starting to doubt it.

The engine starts up usually with just one pull and seems smooth at idle.

Any ideas? Anything electric or spark related? Does this engine have some form of timing advancement as the revs increase? Suggestions?

Thanks for any help
 
Howdy Pat Miller. Welcome aboard the forum.

Your description of how your engine is running has symptoms that could lead in a few directions. But, a big clue that you give leads me to think that it is carburetor related.

To answer your question about timing advance, yes it does have a spark advance "program" in the ignition module that you cannot adjust or, to my knowledge, actively monitor. Sort of "black box magic" that we're not supposed to fool with. I've been around these for a number of years now and have never seen one go bad. But, ANYTHING is possible when you mix water and electronics then multiply by time and thermo-cycling. And, the module also has a built in rev limit feature as well as an engine protection logic that derates the power in the event of overheating. So, you can easily see that the running issues you describe COULD be caused by a faulty engine temperature sensor or wiring or the module malfunctioning. I have had to replace ignition coils on these engines but only a couple of times in about 8 years.

One thing that seems to be missing from your list is spark plugs. Have you looked at them or tried replacing them? Plugs can be pretty "touchy" and hard to predict just by looking. I find that a fresh set of NGK CR5EH-9 plugs can make a big difference if the old ones have been in service too long or if there is another brand installed. Use ONLY NGK plugs! That is something I recommend addressing before anything else.

But your practice of pulling the fuel and running it dry does not suffice to keep the carburetor from experiencing deposits during a layup. You MUST also use the carb float chamber drain screw to remove ALL fuel from the bowl. It is the only way. And now, I have found that a good dose of WD-40 sprayed into the bowl through the drain tube and the drain screw closed while you are still spraying so that the carb is "soaking" in WD-40 during the off season keeps the carb tip-top during storage.

The pages of this forum are full of posts where the skipper took the carb apart and it "looked clean" only to find out later that the carb needed more work. These carburetors can be very difficult to get RELIABLY clean but it can be done using very specific methods. Also, the "jet-set" tube can look clean but have deposits inside that are almost impossible to see. The tubes also have a tendency to crack. Long ago, I stopped trying to clean them and now just replace the tube during a carb service. They are not expensive.

Also, guys will try to reassemble the carb using the old gaskets and seals. This does not always work. A very TINY leak at any of the critical sealing points (orings in particular) will cause all kinds of problems. I don't open a carb up without a gasket and seal set on hand.

The accelerator pump circuit in these is problematic as well and if not kept cleared, will cause performance issues in all ranges of engine operation including causing no start and stall.

Bottom line? These little carburetors are FINICKY! But, if you do learn how to service one properly and then drain and store them as I described, they work well and will give you minimum problems.
 
GJMO Thanks for the detailed message. We did take the plugs out and looked at them. They looked normal in my opinion with a light. Light brown color, certainly not black or sooty. I will get a new set of NGKs based on your suggestion.

I could certainly go through the carb again. So please clarify, I should get a new gasket set and a jet set tube, anything else? Do you soak these carbs in the typical carb cleaning solution?

Another symptom is that the engine sometimes while in gear and throttled up to about mid range, toggle between what I expect as normal, then back to the sputtering condition.

On our engine the pilot adjustment valve has a restrictor type cap, does that cap just pop on and off? At the time I took things apart, I didn't have an exploded view or the carb so I didn't remove that needle valve/screw.

Thanks again for the suggestions and help.
 
Well, that mid range "thing" DOES sound like it COULD be a plug causing a cylinder to drop out so getting new ones in there is a good way to go. If no change, then you will have a used pair as spares. Always a good idea on the water. If your outboard is indeed a 2001 or 2002 then refer to the parts page link below for carb parts. I am using the 2002 since it has a "more complete" list. The boats.net parts site has suffered a bit from neglect in the last couple of years I'm afraid but should suffice for this.

http://www.boats.net/parts/search/Honda/Outboard Engine/2002/BF9.9D2 SHSA /CARBURETOR/parts.html

Item 11 is the tube in question. Item 4 is your idle or "pilot" adjustment and the plastic "cap" or limiter is GLUED on to the head of the screw. It can ofttimes be removed with carefully applied heat from a soldering iron and a bit of prying. You can then reuse it or toss it whichever you prefer. Most guys just cut them off. If you are afraid of black helicopters and the smog police, put it back so that you can sleep soundly at night.

Item 1 has all the seals and then you may choose to go with new mount gaskets, item 14 X 2.

Item 25, cap is the protective dust boot for your accelerator plunger pin. If yours is torn, it should be replaced.

Please try the new plugs first. If you do decide that you want to thoroughly clean the carb after that, I can provide detailed assistance. It is a bit tedious and no, these carbs do not do well in caustic caburetor soaking solutions due to the plastic used in their construction. I use ONLY WD-40 and auto parts store spray carb cleaner. Some guys go with BRAKE clean but I prefer the carb cleaner as it seems to dissolve deposits slightly better. The little straws that come with both of these products has proved invaluable to getting these carbs RELIABLY clean.

Also, if you are willing to spend about $50, you can own the HONDA CARBURETOR MANUAL and TRULY understand the inner workings of these little jewels. Not mandatory, as I have one but worth every penny for any DIYer servicing carbs.

Stay in touch.
jimmyd
 
Thanks Jimmy

so that I order the right part my engine s/n is BABJ1004890

doesnt that signify a 2001. Th reason I mention this is because best I can tell the carb gasket set has a different number for the 2001 vs 2002 models. Please advise Nnd I will order the appropriate one.

Also do you have a p/n for the carb manual?


thank you
 
Hi Pat,

Yeah, I see what you mean.

Unfortunately I don't have dealer access to serial number and parts data base anymore. Sorta retired....sorta.

Hopefully Mike (hondadude) is monitoring this thread and can provide you with that info. Other than that, you can get your local Honda dealer to look it up for you and you should write it down and keep it handy with the outboard.

Are you there MIKE?

Here's a link to the Honda ebay page for the carb manual:

http://www.ebay.com/itm/Honda-Marin...anuals_Literature&vxp=mtr&hash=item3a7e14a296
 
It is a 2001.

Be sure to make sure the accelerator pump in functioning...it is the little silver plunger in the carb bowl. If you do not have the carb apart, you can check it by pressing on the end of the little lever on the side of the carburetor that pushes down a vertical pin that is sealed by an accordian looking bellows.

I am with Jimmy on the spark plugs. It could be electrical.

Pull your safety landyard off and on several times to help clean that connection.

Also reseat the big connector that goes into the CDI unit (about the size of a pack of cigarettes on the front of the engine).

Check the ground wire from that wiring harness to the engine block. I think it has two black wires on the same connector. I have seen the wire break inside the insulation and sometimes it works, sometimes it does not. It may not apply to your situation, since your motor keeps running.

Hopefully, new plugs will fix it.

Mike
 
Thanks Jimmy and Mike......I wanted to follow up and complete this story. I did buy the Hoda Carb Manual....reall has a lot of great info and diagrams. It refferenced my issue as possible jet problems. So I took the carb out a 3rd time, cleaned it with WD 40 reassembled everything and no real change. We then went on to reseat all electrical connectors (they looked great with no hint of corrosion or salt water staining) and changed the plugs.....well that did the trick. The plugs also looked great, but the results paned out. The engine ran great as we took the boat out for a day of sailing. BTW....the correct NGK plugs were in the engine.

We ended up running the engine more than expected as we blew out the head sail in too windy condintion for that sail & motored back to the marina.

It sure seemed like a gas delivery issue.....but sometimes I should take the easier route first.

Thanks guys for the suggestions and support. I will buy another spare set of plugs as I tossed those originals.
 
Glad you got your "gremlins" out! Also, I'm glad you like the carb manual.

While I realize that it was the plugs in this case that were causing your issues, one point I feel I need to clarify is that WD-40 is NOT a great cleaner for "deposits". I use it to pre-flush and test circuit flow as it is relatively cheap and because it will displace water while, at the same time, is not harmful to the carb or most folks skin.

WD-40 is something EVERY boater should have on board to dry out a spark fired ignition system, or any electrical system for that matter, that has been immersed or experienced spray. I have used it many times to start cars after they have been driven through high water and stalled and would not restart. A quick shot of WD on the wires, coils and/or inside the distributor cap and ZOOM ZOOM. MAGIC!

But, for seriously cleaning a carburtetor, you NEED to use the carb spray or a similar solvent to dissolve the varnish and deposits left by gasoline. The WD just isn't that effective for that task. But is is fairly cheap, comes in a pressurized can with a straw and is a good way to conserve the carb spray while checking how effective your cleaning efforts have been as you go.

Thanks for the update and feedback.

I have just one question: What type of boat is it that you are blowing out sails on? That sounds pretty hairy. I'm a big chicken when the wind pipes up and am the first to shorten sail and reef.
 
jgmo said:
I have just one question: What type of boat is it that you are blowing out sails on? That sounds pretty hairy. I'm a big chicken when the wind pipes up and am the first to shorten sail and reef.
Click to expand...

The boat is a 25 ft O'Day fixed keel. We sail in Monterey Bay out of Santa Cruz. The sail was a "drifter" which is a light wind asymmetrical spinnaker type sail. The wind built and we should have pulled it earlier. Our fault for not dropping the sail and putting one up more appropriate for the conditions.

Glad to have the motor back running without skipping a beat.

thanks again for the help you guys
 
You are ONE LUCKY DUCK!! Sailing Monterey Bay out of Santa Cruz harbor!! It just doesn't get more BEAUTIFUL than THAT! :)
 
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