OX66 150 Exhaust leak

[OmarOC1973]

Hi all, new to the forum.

Got a question about my 2003 OX66 150 outboard. I don't recall hearing this ticking sound before. Can someone tell me if it's normal? Here is a video.

While investigating, I also noticed a hole on the lower cowling which I'm guessing shouldn't be there? It's towards the front of the motor, port side (see pics). The motor starts right up and seems to be running well.

Please help.

[Keithbaja]

NO its not normal. Grab a piece of 3/8-7/16-1/2 in fuel line. Stick one end to your ear and other to motor while methodically checking in a organized manner and you should find it. I'd also ck the ox sensor
good hunting

[Tunachaser]

To me it looks like you have a hole in your Exhaust Guide.

Look at the schematic for your motor under Upper Casing and you will see that part. I had the same problem and successfully patched the hole with aluminum epoxy.

Once patched if the ticking doesn't go away try cleaning your o2 sensor.

Let us know the outcome, thanks.


I believe this is your motor.

https://www.boats.net/catalog/yamaha...b/upper-casing

[OmarOC1973]

To me it looks like you have a hole in your Exhaust Guide.

Look at the schematic for your motor under Upper Casing and you will see that part. I had the same problem and successfully patched the hole with aluminum epoxy.

Once patched if the ticking doesn't go away try cleaning your o2 sensor.

Let us know the outcome, thanks.


I believe this is your motor.

https://www.boats.net/catalog/yamaha...b/upper-casing

I believe you are 100% correct.

Would you mind sharing the process you used to epoxy the hole?

I’m in no position to remove the power head myself, and at this point paying a mechanic to replace the part would cost more than the engine is worth. If I can get a season or two out of it (30 or so hours), I would be happy.

Thanks in advance.

[Tunachaser]

No need to remove the powerhead, and on a 2003 you would likely break bolts so... What I did was remove the Cover, CDI unit and Bracket,

https://www.boats.net/catalog/yamaha...b/electrical-1

Be sure to snap a couple pictures before and during disassembly so you get the wire routing the same when you reassemble. Taking that stuff off let's you really get to the problem area.

I used this stuff,

https://www.jbweld.com/product/marineweld-twin-tube

And mixed it per directions but stirred it long enough that it started getting stiff so that I was able to spoon it on with little if any actually falling into the hole.

You'll want to sand around the hole a bit and then wipe it clean, I used acetone but anything would likely work as long as its's clean and dry.

[Reel Vet]

Hi all, new to the forum.

Got a question about my 2003 OX66 150 outboard. I don't recall hearing this ticking sound before. Can someone tell me if it's normal? Here is a video.

While investigating, I also noticed a hole on the lower cowling which I'm guessing shouldn't be there? It's towards the front of the motor, port side (see pics). The motor starts right up and seems to be running well.

Please help.

Did you find out what was going on? My 150 just started making the same exact noise

[zenoahphobic]

Doubt you will get the original poster to respond.
But it seems it was an exhaust leak through that hole, and they repaired it with Expoxy.
Listening to that video audio it didn’t sound like exhaust to me. Towards the end it sounded higher in pitch almost like a spark lead arching.
You will need to record your actual motor, after you do a thorough inspection/diagnostic and can’t pinpoint your problem.

[Reel Vet]

Thank you. I pulled mine apart yesterday and found a hole in the exhaust plate on the power head. Mine sounded almost identical to how his sounded.