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Anyone ever have a badly stuck coil on a 225?

btravlin2

Regular Contributor
I didn't have any luck searching for this problem, but then again, I find the search feature here difficult to use at times. So here goes.....

I had a miss on '04 225 at idle. We popped off each plug wire and found the culprit was the lower port side (#3?). Then we went to remove the coil to inspect the plug and test for spark. Usually these come out easily. This one wouldn't, so we applied gentle pressure, and then more pressure. And then the coil cap detached, leaving the shaft in the hole. Damnedest thing!!

My mechanic buddy paid hell getting that thing out. It took some innovative tooling and cussing to get it out. We were very fortunate the inside of the sleeve wasn't damaged. Finally, we got to the spark plug and removed it. He had 3 coils from another motor, so he hooked up one to test for spark. Nothing. Hooked up another. Nothing. Hooked up a different spark plug. Presto.

So the plug was bad, but.....which came first, a bad coil causing the plug to fail, or a bad plug causing the coil to fail? Or something else?

The pencil part of the coil was nearly "fused" to the inside of the shaft. It clearly had gotten really hot.

Has anyone experienced this, and were you able to draw any conclusions as to what started the whole thing?

We'll have the new plug tomorrow and put it back together and see what happens.
 
My guess is that this cylinder may have picked up water (since it is the lowest cylinder) and the two problems may be independent of each other.....other than water intrusion.

Mike

Oh yeah.....this spark plug was probably not replaced or checked when the other ones were since you have to remove the side panel to get to it. That could cause an issue, even without any water intrusion.
 
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Expanding on what Mike said, if you have not changed out the exhaust tubes IAW Honda Service Bulletin #56 it is very possible that there was water intrusion in the lower port cylinder. It is also possible that you have a failed HO2 sensor and don't know it because there may be no alarm. Pull fault codes and see if you get a code "1". If you need a copy of the SB, send an e-mail to me at [email protected].

You can get a kit for somewhere around $150 on Boats.net to replace the exhaust tubes with re-designed ones that prevent the problem. The SB gives all of the part numbers you will need. The labor time is fairly intensive, but several folks on this forum have done the job themselves. The SB walks you through the entire procedure.
 
My guess is that this cylinder may have picked up water (since it is the lowest cylinder) and the two problems may be independent of each other.....other than water intrusion.

Mike

Oh yeah.....this spark plug was probably not replaced or checked when the other ones were since you have to remove the side panel to get to it. That could cause an issue, even without any water intrusion.

So are you saying that if a spark plug fails it causes the coil to overheat? Does that mean that anytime a plug fails the coil will fail right behind it? Or, if you catch the plug early enough, it doesn't take out the coil?
 
Expanding on what Mike said, if you have not changed out the exhaust tubes IAW Honda Service Bulletin #56 it is very possible that there was water intrusion in the lower port cylinder. It is also possible that you have a failed HO2 sensor and don't know it because there may be no alarm. Pull fault codes and see if you get a code "1". If you need a copy of the SB, send an e-mail to me at [email protected].

You can get a kit for somewhere around $150 on Boats.net to replace the exhaust tubes with re-designed ones that prevent the problem. The SB gives all of the part numbers you will need. The labor time is fairly intensive, but several folks on this forum have done the job themselves. The SB walks you through the entire procedure.

Chawk, I'm trying to avoid the exhaust upgrade because I've got 8" minimum clearance from exhaust ports to waterline. And I'm about to add two more inches with some foam flotation that I'm making for the engine bracket.

So I don't think I will have a problem with water intrusion, BUT......I don't know the history of these motors. I bought them out of Florida last Nov. I don't know what boat they were on. They could have been mounted low and gotten water in the lower cyclinders.

On the subject of O2 sensor......the threads seem to say that a failed one doesn't stop the motor from running properly, it just robs fuel economy. So, even if water got in and knocked out the O2, why would that have killed the spark plug? Or is a failed O2 sensor unrelated to a failed plug?
 
IMO the motors will take a wave on the back end, thats just the way mother nature works. But why risk damaging an O2 sensor, cylinder, etc... it's only a matter of time. SB56 is very easy to do and less costly than replacing an 02 sensor, and while your at it, you can replace water pump impeller.
 
IMO the motors will take a wave on the back end, thats just the way mother nature works. But why risk damaging an O2 sensor, cylinder, etc... it's only a matter of time. SB56 is very easy to do and less costly than replacing an 02 sensor, and while your at it, you can replace water pump impeller.

It's all about time, Skooter. It's a lengthy job, meaning I have to do it myself because I won't pay $100/hr for someone else to do it. But I'm working too much right now. Maybe in Winter I can. For the time being, I have to make do.
 
OK on avoiding the upgrade, but as Skooter said, if you're offshore in heavy following seas, water can still get in there. Also, according to SB #56 if you crank the engines and they don't start right away, and you stop cranking at just when either of the bottom cylinders are at TDC, a slight kickback can suck water in through the exhaust port.

If the spark plug was totally shorted, it could definitely cause the coil to overheat and fail. It's rather unusual for a plug to fail that way these days, but you would see it fairly often in older cars - we're talking the 50's and 60's. And if the plug hadn't been changed for a long time, then the probability of it happening would certainly increase.

Yes, these engines will seem to run fine with a failed HO2 sensor. The give away is black streaks at the exhaust ports. Water could have gotten into the lower cylinder(s) without blowing the HO2 sensor. See above.
 
Follow-up. I still recommend pulling any fault codes. Also, I think you should do a compression test to make sure those lower cylinders still have good compression.
 
The confusing thing about pulling codes is that, according to searches here, a "1" can be a number of things: O2, coil, plug, low fuel pressure, maybe others as well.

Also, I can't clear codes to start fresh because I don't have the kill switch hooked up.

I've got a double-dose of Ringfree in the tank, but that will take awhile to work through.

Mainly, I just wanted to understand how that coil got so hot that it nearly fused to the inside of the sleeve. This is a slow process of bringing these motors back up to spec, so it's one issue at a time.
 
You are correct about code "1" but it points you in a specific direction. Each of those items can be tested - HO2 sensor, plug, coil, fuel pressure.
 
You are correct about code "1" but it points you in a specific direction. Each of those items can be tested - HO2 sensor, plug, coil, fuel pressure.

Really happy I found this thread. Having the exact same problem with my 2003 BF225. I have twins with about 600 hrs. Just replaced all the plugs, and the lower left cylinder in both was a bit funky. On the one motor the coil came out no problem but the plug itself was a bit stuck. On the starboard motor the coil pack is seized and snapped just as described. Question; when you finally got the coil pack out, how hard was it to get the plug itself out? Basically trying to see if I can do this myself
or just take it to a mechanic so I don’t damage my powerhead. Thanks.

-Carl
 
The best DIY solution would be to put some PB Blaster down in there and let it soak into the threads overnight. Then get your socket securely on the plug and tap, tap, tap and bunch of times until it gets loose enough to turn out. In the past, I've used an impact driver to work them out, but that was on a steel head. Not ever tried it on an aluminum head. Worst case scenario that you will end up removing the head to get the plug out and likely need to put in a Helicoil.
 
I had a stuck plug (bottom right) on 225 that we'd had for 12 months but the shop didn't change this plug along with the others when it was serviced.

Although I heated the engine up the thread still stripped when the plug came out. In the end I had my local car garage fit a Time-Sert without removing the head - there was a a bit of aluminium swarf in the cylinder after it was fitted but I sucked most of it out with a cleaner and then turned the engine over without the plug in to blow the remaining bits out.

Engine has been fine ever since and the plug still comes out easily each year for its inspection and thread greasing.
 
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