Yamaha 150XB overheat warning while flushing

chicy724

Cadet
Joined
Jul 13, 2010
Messages
18
Hello,
​​​​​After a day on the water yesterday we came home and did our thing, flushing the engine and cleaning the boat.
I was inside when my other half started the flush cycle (muffs, per our certified Yamaha tech). He told me it took a little bit for it to start peeing through the tell tale hole, but it was peeing. We proceeded to soap up the boat and then I heard a light buzzing sound. I shut off the engine, as I was thinking it was the overheat warning sensor.

Other half checked the muffs and made sure the water hose valve was all the way up. We then restarted the engine and waited (for what seemed like forever but was maybe a minute or less), and no water was coming through the tell tale hole. So I turned it off, other half ran weed wacker line up the pee hole to try and clear it, I waited a few and then restarted it again. Still no water through the tell tale after 10 or so seconds, so I shut it off.
I also ran the weed wacker line up myself a few times, all the way through until it stopped. I did not try running it again after that, though. By that point I was too afraid to start it again and cause damage (hoping we didn't already!)

The alarm only went off that one time.
We then flushed through the flush port on the side since we had only been able to flush on the muffs for maybe 5 minutes.

We usually flush it for 15 minutes on the muffs after use, per our Tech 's and other's recommendations.

We run in saltwater, and do go to sandbars.
We have approximately 40 or so hours on the engine. It's a 2016 Yamaha 150XB.

We just had annual service done, and changed the impeller, waterpumpw, oil, etc. which was all done by a Yamaha Master Certified Tech. We have now used it twice since this annual service was done.

I suppose it's possible it got clogged at the sandbar yesterday.. because we just had it serviced and it's a new impeller, pump, etc.

Any thoughts on what our problem could be? Any suggestions on what someone like me, with no experience could easily do?

I'm not afraid to bring it to the shop and pay to get whatever it is corrected, but if it's something silly i'd like to avoid that.

Thank you!
 
Last edited:

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
8,917
lots of the larger outboards need more water than the muffs can supply. you can always hook up to both the muffs and the power head flush to make sure it gets enough water while running the motor
 

tommarvin

Ensign
Joined
Nov 22, 2015
Messages
999
I had no idea you could use the power head/back flush and the muffs at the same time thank you 99yam40 for that tip.
I think its like over 70hp you need the muffs where water goes in both sides of the lower unit intake.
We had the same problem on our force 125hp no water came out and the head temp got to 180F shut her down, pondered it for awhile then i made a deep wood box as high as possible,filled it with water started the motor the water stream started within 15 seconds the point muffs dont work all the time, we had tos shut down our twin 115hp Mercurys both did not have a water stream when started at the ramp one time. We tilted both of them up all the way tilted both down started them both water stream in 15 seconds.
 

chicy724

Cadet
Joined
Jul 13, 2010
Messages
18
Thank you for the info.
I failed to mention that we do have dual flush muffs.
I did not know you could hook both up. That'll be tricky to get two hoses hooked up (need to get a dual mount for the faucet and another hose).

Hopefully that's all it is, but I'm almost afraid to try again and overheat! I'm worried we already did.
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
8,917
How about backing it into the water on the trailer and firing it up to see if it has a tell tail.

also you can put a Y on the end of a Good hose and feed both from there with short hosed you make from a longer one with new ends
just make sure you use a large diameter hose to feed it all. do not want to restrict the water flow
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
If the powerhead has a dedicated flushing port flush it direct with hose and adpter if needs one. Will provide a higher water output to flush efficiently the entire powerhead compared to muffs use. Muffs always loses precious water pressure through both rubber sides.

Happy Boating
 

Bengal

Recruit
Joined
Oct 2, 2018
Messages
5
Remove the plastic gaurd to get more water flow into the engine when using the muffs
 

BaileysBoat

Senior Chief Petty Officer
Joined
Sep 29, 2008
Messages
716
lots of the larger outboards need more water than the muffs can supply. you can always hook up to both the muffs and the power head flush to make sure it gets enough water while running the motor

you need both like 99yam says--if you don't use the muffs with the flushing port the water pump runs dry.
 
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