Problem with BF15 Tell Tail

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I have a Honda BF15A outboard with a persistent issue with the tell tail.</p>
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Several months ago, whenever I started the engine, no water would stream from the tell tail, and quickly the engine would seem as if it were overheating. I cleared the small hose and the plastic engine casing fitting. I even started the engine with this hose detached from the block. Upon starting, the engine would stream water from the block for about 15 seconds, then stop and emit smoke instead.</p>
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I brought the boat to my local Honda dealer. The found the lower unit rottted under the water pump, in other words, no water was getting pumped into the engine. They also found a corroded thermostat. Ultimately, they repaired the lower with epoxy, replaced the impeller, the thermostat, impeller pump, spark plug, and all gaskets. I started the engine while at the dealer, and the tell tail worked perfectly, but the engine ran rough. They diagnosed a bad coil and replaced that too.</p>
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Yesterday, I picked up the boat and took it home...about a 5 mile trip. I noticed under way that the tell tail did not work for the entire trip. The engine ran great and did not seem to overheat at all. The air temperature was about 42 degrees.</p>
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Today, I tested the engine at the dock. It started right up, but still no tell tail, only a small amount of smoke - not nearly as much as before the servicing. I noticed the water gurgling at the prop indicating that water was circulating through the engine. I put my finger over the tell tail nozzle and felt no pressure, but when I released, a small stream came out for a few seconds.</p>
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Can anyone provide insight as to why my tell tell is not working? Thermostat, impeller all new. Engine ran for over an hour and did not overheat. And yet, a month ago, the tell tail worked find before changing the coil, which is unrelated. Is there any time a tell tail will not stream water?</p>

Tell tale should operate anytime engine is running. Sounds like yours is clogged again. try sticking a piece of wire up it and see if any water comes out or try running a hose to your flush line while the engine is running the extra water might push out whatever is stuck in there. Could be piece of shell or slag from the lower unit repair If you have plastic nozzel on the end of tell tale hose that holds it to the colwing pull it off and look down inside it might have something stuck in it. shoot it with a garden hose from the pissing side. while pisser nozzle is off, run engine and see if any water comes out tell tale hose use flush hose for more water presure if not flowing. I've had engines make sand castles in my hand then flow freely.

Check your water bypass tube (rubber hose). If it is "rock hard" it probably has scale built up inside that can act as a trap for debris. If so it's no longer available but you can make a new one out of two different sized hoses and some 3m5200 or other sealant.

Reference item 16 in link below as an example.

Good luck.

I'm guessing you gave your dealer a pretty penny for their efforts. The fact you didn't even make it home after that repair would have me taking it back to them so they can see what happened....

Here's another view of "water tube". Sorry for it being all over your thread but just wasn't clever enough to get it all on the same post.

https://www.boats.net/catalog/honda...s-vin-baas-1500001-to-baas-1599999/water-tube

Good luck.

Alan Hicks said:

I'm guessing you gave your dealer a pretty penny for their efforts. The fact you didn't even make it home after that repair would have me taking it back to them so they can see what happened....

Click to expand...

Actually, I did make the entire 5 mile trip back home. By the time I realized the tell tale was not discharging water, the dealer had closed. The engine did not overheat which would have happened if water were not circulating.

Number 6 said:

Actually, I did make the entire 5 mile trip back home. By the time I realized the tell tale was not discharging water, the dealer had closed. The engine did not overheat which would have happened if water were not circulating.

Click to expand...

None of this changes the fact it's not working correctly, or that you likely gave them a lot of money to get it "fixed"....

jgmo said:

Check your water bypass tube (rubber hose). If it is "rock hard" it probably has scale built up inside that can act as a trap for debris. If so it's no longer available but you can make a new one out of two different sized hoses and some 3m5200 or other sealant.

Reference item 16 in link below as an example.

Good luck.

Click to expand...

Thank you for the reply.
Here is a photo of my engine. My finger is on the small nozzle off the manifold that the tell tale hose attaches to. From the diagrams you shared, it appears that the water bypass tube is the hose to the left of my finger coming off the thermostat. What exactly does this hose do, and how does that relate to the tell tale?

Tried to upload a photo from a shop manual but I have had nothing but problems using THIS site since my phone last updated. Had to change web browsers to even be able to post here. Sorry.. I don't have the BF15 manual anyway so I was trying show you a diagram from a B100 manual which should be very similar. Maybe HonDan can post something for you since I believe that he has the specific manual.

That hose delivers water to the intake manifold as well as exhaust manifold for when the thermostat is closed and won't allow water to exit the cylinder head. It is fed from a "T" passage at the base of the engine block where coolant enters the engine from the water tube feed from the pump.

BUT...
If that hose gets substantially plugged, it will still interfere with flow through the tell tale even if the tstat is open because it will create a sort of "lock" condition that resists flow through the system. Kind of like putting your finger over a straw and then picking up any liquid in the straw.

Probably not the best example I could offer but suffice it to say that the hose and that "circuit" needs to be unobstructed and free flowing at all times for the water check (tell tale) system AND the cooling system to perform properly.

Good luck.

jgmo said:

Tried to upload a photo from a shop manual but I have had nothing but problems using THIS site since my phone last updated. Had to change web browsers to even be able to post here. Sorry.. I don't have the BF15 manual anyway so I was trying show you a diagram from a B100 manual which should be very similar. Maybe HonDan can post something for you since I believe that he has the specific manual. That hose delivers water to the intake manifold as well as exhaust manifold for when the thermostat is closed and won't allow water to exit the cylinder head. It is fed from a "T" passage at the base of the engine block where coolant enters the engine from the water tube feed from the pump. BUT... If that hose gets substantially plugged, it will still interfere with flow through the tell tale even if the tstat is open because it will create a sort of "lock" condition that resists flow through the system. Kind of like putting your finger over a straw and then picking up any liquid in the straw. Probably not the best example I could offer but suffice it to say that the hose and that "circuit" needs to be unobstructed and free flowing at all times for the water check (tell tale) system AND the cooling system to perform properly. Good luck.

Click to expand...

Thank you for the detailed response....and now the plot thickens... Yesterday, I started up the engine before checking for any clogs. The tell tale was spraying water, not a full stream, but more part of a mist. (photo attached). But at the same time, the engine was running rough seeming on one cylinder. This happened when my engine was at the dealer and they diagnosed and replace a bad coil. So I had a partial tell tale stream, but the engine kept bucking harshly. I reached across the top of the engine to put my finger over the tell tale hole to feel how much pressure was coming out of the hole. All of a sudden, the engine was firing on both cylinders. Apparently, I accidently touched a black box on top of the engine and the engine started to run properly. I shut off the engine and restarted to duplicate the fix. It ran on one cylinder until I touched the bracket shown in the 2nd photo. I researched this box and appears to be the Ignition Control Module. Is fixing this ignition issue as simple as cleaning the contacts on the bottom? Or will I need a new unit? Back to the tell tale issue... While I was able to duplicate the "fix" of the electricial issue, the tell tale was still spraying, not streaming water as seen in this video: https://drive.google.com/file/d/15qtOVYqrBA67k45CCfucslI84zZFgD7-/view?usp=sharing I shut off the enging and restarted, and the tell tale streamed properly as seen here: https://drive.google.com/file/d/15TNahIS2-fuZxqrp8zpdT5kUnQVbJZDA/view?usp=sharing

Hey number 6,
Well, from where I sit, all I can do is guess at the answers so here goes:

As far as the ignition control module, I don't think you have any choice but, at first, to try unplugging it and seeing if you can clean the pins and connector sockets as best as you can. You will want to remove any corrosion you find but you need to be careful not to bend any pins or enlarge any sockets. Use a good contact cleaner like DeOxit. You might need to gently scrape at any build up with something small and sharp like a pick with a bent end or even the end of a paperclip shaped to do the job.

It's important that you make sure all the pins have a "drag fit" in the sockets. Sometimes a VERY MINOR twist of a pin with a small needle nose plier can improve the way sockets and pins fit together but be very careful doing that. If cleaning the connections doesn't work, you may need to replace the ICM. Not cheap!

As far as what I see in the videos it appears to me that there is some obstruction in the tell tale circuit. Just my opinion but I think it should be flowing better than what I'm seeing in the second or "after" video.

But, it IS flowing and that's good. If you can get the engine to run correctly and it doesn't overheat then you might be able to operate it ok as is. You will just have to use your own judgment as to how aggressive you might want to get trying to clean the tell tale circuit and improve the flow.

Again, caution needs to be observed. This outboard is old and I guarantee you that there are scale deposits in the intake manifold water passage and in the bypass hose. But I know from experience that trying to do too much with these old girls will often create more trouble than it's worth. Those deposits embed into the metal and trying to dig them out can end badly. If you damage or break a part that's no longer available then you can't use the outboard at all.
Sometimes leaving well enough alone is the best thing to do.

Good luck.

Another possibility that comes to mind about the ICM and how touching the mount seems to change the way the engine runs is the wiring.
These engines vibrate quite a bit and over many years of running the wiring might get "stressed" by the movement. I have seen multi-strand wires broken right at the crimp where they attach to the connector.
Just something else to keep in mind as you try to figure this out.

Hope you get-er-done!