Yamaha VZ225TLR Overheat horn above idle

[wwjd]

Motor is on a 2007 Champion SX21 has less than 50 hours total. Earlier this season same problem occurred. Poppits were cleaned and water pump impeller replaced precautionary. The original water pump looked unworn. Now the engine is again overheating and limits rpm to less than 2000. Problem started when allowing motor to warm up yesterday. The horn came on steady I immediately shut-off the engine. Later after it cooled down I tried it again. Motor started as normal set out got up on plain and about 10 minutes the horn sounded again.

Engine is always rinsed for near 10 minutes after boating.

Any ideas anyone?

 

[rodbolt]

Re: Yamaha VZ225TLR Overheat horn above idle

how are you sure its an overheat?
what icons are lit on the yamaha digital tach?

 

[wwjd]

Re: Yamaha VZ225TLR Overheat horn above idle

The engine was cooking off the Corrision-X I put on earlier in the season with smoke coming from the cowl vents which I could also smell. It had not gotten that hot before. I do not have the indicator lights with my instrument package. The only signal I get is the horn coming from the throttle lever. Well I do have Amperage meter, speedometer, tach, fuel quantity gage, and trim indicator.Oh and excessive exhaust smoke intermittently from the exhaust. The tattle tail still has flow but I perceive it to be weaker.

 

[99yam40]

Re: Yamaha VZ225TLR Overheat horn above idle

When was the last time the thermostats were tested or replaced?

It is best to replace the wear plate and cup when changing the water pump, usually just a few dollars more for the kit instead of just impeller.
I have found impellers missing rubber in less than 1 year if started dry for just a few seconds, would not hurt to check it again just to be sure

 

[rodbolt]

Re: Yamaha VZ225TLR Overheat horn above idle

another poorly rigged bass boat.
time to go through the cooling system, again.
also check the jack plate height,if used.

 

[wwjd]

Re: Yamaha VZ225TLR Overheat horn above idle

My main concern is causing damage to this fine machine.

I hope that I have not done something that cannot be

corrected with cooling system components. I listened when

the horn sounds and idle back to port. Will this still hurt the engine?

The jack plate was set by the tech that did the last work.

I believed it to be too high because I could not get up on plane

without cavitating the prop. So I split the difference of what

the tech set it at and lowered it by 2". This solved the getting

up on plane issue. I did not think it could be starving the inlets

for water. Is that what you are referring to by saying it is rigged

wrong? Please clarify.

 

[yamamarinetech40]

Re: Yamaha VZ225TLR Overheat horn above idle

I believe that Rodbolt is referring that you have less than what a 'fine machine' such as this requires in a gauge package....the proper Yamaha digital gauges for this engine would show you the SOURCE of the alarm with icons... yamaha does make analog/basic gauges for some apllications...not this one.You may not be oiling correctly...causing overheat and a COOKED engine....the SLOW mode that allows you to limp home is there to save you if out to sea or big lake and NO other way to get home(tow,etc) not as a convenience.... your owner's manual explains this....but anyway...too often the people rigging/selling boats go cheap on gauges and sell for same price....stick around and listen to Rodbolt....best on here. Good luck.

 

[wwjd]

Re: Yamaha VZ225TLR Overheat horn above idle

Today we took the lower unit off and found a melted housing. A small piece of it was blown out. Compression was 125 on all cylinders. Replaced water pump and housing. Pressure checked lower unit because only about a cup of oil was drained. The seal held pressure to 18 psi where it started to leak. No water was in the oil so I decided to refill and just keep an eye on it. The horn problem is corrected and the once weak tattle-tail is strong. This is a great boat and engine is most reliable except when I warm it up in the sling without having the red line well under.

 

[rodbolt]

Re: Yamaha VZ225TLR Overheat horn above idle

and thats what melted your pump.
why not dunk it first .