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06 BFA40 issues

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Bubbamanboomer

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I have a 2006 BFA40 was running rough. Took off carbs/intake completely broke down carbs cleaned installed new float needles double checked float levels all new gaskets installed still rough chugging idle and black soot on plugs exhaust indicating rich. Carbs were set and synched as well. Carbs removed and double checked twice. Compression test was 180-178-180. I am stumped at this point. Any ideas or experience with this much appreciated.
 
Hi,

Compression seems acceptable.
Are you running fresh NGK DR7EA
spark plugs?

I don't know this particular model but I'm very familiar with the Keihin carburetors on several Honda models.

I see from the parts list this outboard has a Service Enrichment system instead of a conventional choke. Please correct me if that's wrong.

If you have an SE valve in the #1 (top) carburetor then I suspect that there may be an enrichment issue with the SE valve or with the power that leans the system out after warm up.

The SE system is always defaulted to rich when the engine is off.

After start up, a dedicated mag coil under the flywheel starts supplying voltage to the SE valve.

After about 3 minutes run time, the electrical heater coil inside the SE valve causes a wax pellet to melt. The melting wax expands and pushes the enrichment pintle valve down against spring pressure and closes off the enrichment passage leaning out the air/fuel mix. The system stays in this configuration until the engine is stopped.

Things that can go wrong:

The coil under the flywheel doesn't supply voltage to the SE valve after the engine starts.

The SE valve heater fails to melt the wax pellet and the needle valve doesn't extend.

The SE needle valve gets scratched and won't seal.
Or, the seat gets worn and won't seal (very rare in my opinion...I've never seen that happen).

You can unplug the SE valve and check that the coil under the flywheel produces voltage after start up. If not, check the continuity of the coil and wires at the connector. I don't have resistance value for that coil. Sorry.

You can remove the SE valve and apply 12volts to the SE valve connector and observe that it fully extends after 2 or three minutes. Be careful not to get burned doing this as the SE valve gets very hot!

I Don't have the 40hp shop manual but my 20hp manual says Positive to brown/white and Negative to black/green.
It also lists resistance as 15.8 to 24.2 ohms.

Based on what you said the symptoms are, that's my best guess as to what to check from my not so easy chair.:)

But, if the enrichment system checks out good, I would then suspect a possible timing or valve adjustment issue even though the compression numbers look "ok".

Good luck.
 
Ok, well, my information is limited for sure and boats.net only lists 3 outboards under 2006 40 hp. and they all are SE valve equipped
so I don't know.

Do you have the frame number?
I might be able to verify year model by that if you don't know for sure.

Is this a recent purchase?
If so, I suggest checking timing and valve lash. An engine without poorly adjusted valves and/or slightly out of time can have acceptable compression readings but not perform as well as it should.

Unless the manual choke isn't opening all the way or someone has fudged the jetting, I don't think the carbs would be causing a rich condition like you describe.
Although, you might check the enrichment check valve and make sure it's installed with the arrow pointing toward the carbs. I have read that, if installed backwards, it could cause an overly rich condition. But that would only be during decel I believe.

Good luck.
 
Well, if you were told you have a 2006, I think that was bad information.

I've purchased parts for Hondas from boats.net well over a decade and know that their system is very accurate. Their parts are genuine Honda inventory.

According to boats.net your frame number is for a 1999 year model. See link below


The 2006 model year frame number starts with BAYS 360XXXX...Link below.


I don't know but it is possible that someone has changed jets on your carbs. The "sea level" main jets for your carburetors are supposed to be.#92 while the 2004 and up are listed with standard main as #105 with higher elevation optional jets going down in size ie: #102 and #100 available with one other (likely #98) listed as unavailable.

I'm sure the main emulsion nozzles and low speed tube sizes are different too but can probably be fit in there.
I didn't look. But I hope you see my point.

People that don't know or are looking to boost power will be tempted to change that stuff without realizing it's not usually a "plug and play" swap. It often doesn't work well because of other factors like cam timing and air jet
changes in the carb body that only the engineers can explain. Or, horsepower geeks much smarter than me.

But someone doing that or, WORSE, hogging out what's in there with a.file, is something you have to consider when you get a problem with how the engine runs and you can't explain why.

It could be as simple as the choke solenoid return spring has gotten weak over the years and it IS staying enriched that way.

Just some guesses what you might look for to get it sorted out.

Good luck.
 
The 2006 on the sticker on the engine cover is about it meeting 2006 emissions. Honda put that sticker on all outboards about 1998.
 
Bubbamanboomer said:
I have a 2006 BFA40 was running rough. Took off carbs/intake completely broke down carbs cleaned installed new float needles double checked float levels all new gaskets installed still rough chugging idle and black soot on plugs exhaust indicating rich. Carbs were set and synched as well. Carbs removed and double checked twice. Compression test was 180-178-180. I am stumped at this point. Any ideas or experience with this much appreciated.
Click to expand...
I had a 2006 Kehin carbureor with enrichment valve. The motor was running rough, fouling plugs in mere minutes. The valve wasn't the problem, it was a missing access plug for removing the pilot jet. The previous owner of the outboard left it out after cleaning the carb. Without it in place the pilot jet draws unmetered fuel directly from the float bowl causing a super rich mixture to make the engine run rough and foul plugs. It sits in the access hole beside where you remove the main jet. Took hours to discover the problem
I have never seen a pilot jet under a rubber plug before.
Hope this helps someone.
 
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