2006 Yamaha 250 VMAX SHO

[Tigerfly23]

So I bought my first boat last summer. It has a 2006 Yamaha 250 VMAX 2-stroke that tested well and ran very well for the first few trips. I put maybe 20 hours on the engine, then after that, the heat alarm would turn on while at low idle. Spoke with a few guys and this was chalked up to the VMAX wanting to idle higher. Probably two trips (maybe 7 hours) later, I was on plane and cruising when the engine dropped into limp mode and the heat alarm just stayed on until I got to the ramp (about 45 minutes of screaming alarm) and killed all power. Got home flushed the motor as per usual and the alarm immediately cut on when power returned. The only thing I can think would be a problem with the external oil tank but I’m kinda lost. The boat could use a re-wire anyways so I could bypass the external oil tank if necessary. TIA.

 

[99yam40]

guessing at what is causing the alarm is no good,
and running the motor with the alarm sounding for 45 minutes is a bad Idea. what do your gauges tell you is happening when the alarm sounds?

 

[boscoe99]

Keep running that motor when the alarm is trying to tell you to turn it off is a terrible idea. Hopefully, you have not damaged the motor.

You cannot bypass the main motor mounted oil tank on a VMAX HPDI model if this is what you have. Well you can but it won't last long. Is the model of the motor not known to you?

Too things normally sound the alarm. Over temperature and low oil quantity in the main motor mounted oil tank.

Sounds like you do not have a Yamaha tachometer that will tell you why the alarm is sounding. But you say that the heat alarm came on. How do you know that it was a heat alarm?

 

[Tigerfly23]

Keep running that motor when the alarm is trying to tell you to turn it off is a terrible idea. Hopefully, you have not damaged the motor.

You cannot bypass the main motor mounted oil tank on a VMAX HPDI model if this is what you have. Well you can but it won't last long. Is the model of the motor not known to you?

Too things normally sound the alarm. Over temperature and low oil quantity in the main motor mounted oil tank.

Sounds like you do not have a Yamaha tachometer that will tell you why the alarm is sounding. But you say that the heat alarm came on. How do you know that it was a heat alarm?

VMAX SHO HPDI, I don’t have the model number off hand. I was still getting oil movement which threw me. Temps were showing in operating range on tach. Finally fuel was moving normally. The auxiliary oil tank is still feeding the motor mounted tank and the motor mounted tank is holding oil.

 

[99yam40]

the gauges should indicate what the alarm is from.
a light or some other indicator, depending on what gauges you have

 

[boscoe99]

VMAX SHO HPDI, I don’t have the model number off hand. I was still getting oil movement which threw me. Temps were showing in operating range on tach. Finally fuel was moving normally. The auxiliary oil tank is still feeding the motor mounted tank and the motor mounted tank is holding oil.

Do I presume correctly that you have a Command Link tachometer? The kind with bars that show some indication of temperature range?