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Honda40 four stroke no spark #1 cyclinder

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Vegas99

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Hi all I need help my sons honda 40 has no spark in #1 plug. Put new plugs nothing, switched coils from number 2 no spark still. Any thoughts on this. Thanks for your help on this Daniel
 
What year is the 40? If you are not sure....what is the frame serial number? Carbureted engine or fuel injection? The 40 could be either.

How do you know there is no spark? Can you see spark on the other cylinders, but not on #1? Or...are you pulling the spark plug wires off and the cylinder does not drop off?

No spark in one cylinder could be coil (which you have already ruled out), one of the pulsars or the CDI.

If the output from the pulsars are all good, that would mean that the input to the CDI is good for all the circuits, but the output is not ok. That would then point to the CDI.

Test test test.



Mike
 
Carbureted rebuild went well. Serial number is 00372 first two numbers I can't read. Pulled the plug looked for spark non. Pulled plug wires while running 2 and 3 when pulled you can hear motor fall off. Pull top no change at all. Thanks for your help
 
A partial serial number does not help....Any idea of the year?

It is very unusual for these things to have a spark issue...although it does happen.

The spark is very small. Can you see the spark on one of the cylinders that is firing? Just to double check your method of checking spark.

I can not tell you how many times someone says there is no spark, but it turns out to be the carburetor (even though just cleaned).

If there really is spark, check the resistance of each of the pulsar Blue lead to black lead or blue/yellow lead to black lead or blue/green lead to black lead. Should all be about the same and around 288 ohms to 352 ohms. You could also check the voltage outputs of each of these while the motor is cranking. I do not remember what the voltage is supposed to be, but it is fairly low.

If all that checks out good and all connections are good, the it is probably the CDI.

Mike
 
I am having the same problem with my 2000 BF40A. cleaned out carbs twice because i forgot the low idle jets the first time..:rolleyes: Engine had been sitting for a few years so that got it going. But when i went to adjust idle and syncronize it wouldnt co-operate . Idle would go way high then low, then fluctuate. Started pulling my plugs and carb 3 wasnt firing? pulled plug no idle change (gas on plug). Think i narrowed mine down to bad #3 ignition coil. primary was .3 ohms and 11.85k on the secondary. my other coils measured .3 Primary and 13.86k Secondary. I am pretty sure this is the problem. Checked the pulser coils everyone around the 320 Ohm mark. Does anyone have the spec for 2000 ignition coil for a BAYE-2008XXX motor. in my repair manual it says .19 to .23 Ohm Primary and 2.8k to 3.4k for the secondary. There is no way these values are correct. Hopefully there isn't anymore issues..

I would test your coils first. Easy to do and compare them with good ones.
 
Ok so my first mistake is its a 25 hp not 40. I don't know why I put 40. Anyway changed cdi have spark in top cylinder now, however not running on top cylinder. If I pull plug wire on 2 or 3 it bogs down nothing on top. Checked coil, cleaned all connections I am still baffled on this any more help would be appreciated
 
If you are POSITIVE it has spark, that indicates that you likely have a fuel delivery issue. You mentioned "carbureted rebuild went well". Did everything get put back on as it should?
The only other reason a cylinder with good spark won't fire besides lack of fuel would be a problem in the cylinder itself.
If you have good spark here's how I would proceed:
Try artificially enriching that cylinder with propane gas. A plumbing torch from your hardware store makes a great tool for doing this.

If adding fuel works, then the problem is still with the carbs.

If adding fuel doesn't have the cylinder coming on line then the problem is likely with the cylinder itself. A compression comparison between that cylinder and the working ones will, hopefully, yield some good diagnostic info.

If you find low compression in the cylinder then your valves could need adjustment or you may have stuck piston rings.Doing a valve clearance check and/or adjustment isn't too difficult at all. And getting rings "unstuck" is done all the time utilizing any number of methods and materials/products.

There is another handy tool that Harbor Freight has made available and affordable to the DIY GUY. It's called a cylinder leak down tester. Using it can quickly tell you where the majority of the pressure leakage is occurring in a cylinder with low compression.

As you can see, there are still many areas to check for this type of issue. The good news is that it's more than likely fixable once you narrow it down doing some more testing.

Good luck.
 
Ok so I have spark now and redid cards again, idles great when you put it I gear and give it throttle it bogs down and stalls. I'm scratching my head
 
What year 25 is it? Post the frame serial number, if you can find it. Then we will know for sure exactly what you have.

The carburetor setup is not the same for all years of the 25 hp.

Mike
 
Ok....you have a D4 model, which is 2004

If you have spark and you have good compression and timing is where it should be, the only thing left is fuel.

I doubt that bypassing the water separator will fix it. If you squeeze the fuel bulb, that should fill all the carburetors with fuel.

I would go back to the carburetor.

Pull jet set #21 out and make sure that you can see through it. The hole is pin size. If clogged, that cylinder will not function at idle or acceleration.

http://www.boats.net/parts/search/Honda/Outboard Engine/2004/BF40A4 LRTA/CARBURETOR/parts.html

The pictures of #7 bowl is deceiving. There are passages in the bottom of the bowl that feed fuel to several places. Sometimes they are very hard to clean out.

While you are looking at the bowl, this vintage 25, has had some starting issues in the past. There should be a number engraved in the bowl just above the drain nipple. It should either say 75 or 70. If it says 70, it has the updated bowl. The bystarter #18 number will start with DE or DR if the number on the bowl is 75....and will start with HH if the bowl says 70.

I am just saying that, in case you have to change the bowl, you want to order to updated bowl and bystarter, if they are not already there. This change was for start up problems, not running problems.

Back to the carburetor....

Once the carb is apart, notice there are several pin sized holes at the top of the back of the venturi. When the butterfly is closed only one can be seen from the back of the carburetor, when it is open you can see them all.

Those holes provide the fuel to the motor at idle and during acceleration/transition.

You need to be sure that fuel is flowing good through those.

Using WD40 or Brakleen with the straw, stick the straw up through the bottom into the hole that the jet set (skinny tube) goes at the top of the venturi. Spray the Brakleen into that hole and make sure that it has a good spray out of all of those holes. (make sure you idle mixture screw is in place at that time). If you do not get a good spray, you may have to backprobe the holes, etc to clear them out. If they do not spray good, the cylinder will not fire at idle.

Other places to check, are the black hoses on the back of the carburetors. They are carb bowl vent hoses and may get plugged up by muddobbers or other critter debris.

Mike
 
Thank you all for your help, amazing knowledge you all have. Took the carbs off again the little set screw that squirts into bowl was clogged, and vacuum was clogged she runs great now
 
You didn't give up so you had SUCCESS!
TENACITY is often the key to repair.

GOODONYA and....as Mike said...thanks for letting us know what you found. It will help someone else get theirs going when they have a similar problem.
 
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