TLDI rev limiter behavior

[whosmatt]

Motor is a new TLDI 50 with about 15 hrs. Was testing a new prop today and was able to trim out a LOT more than the factory prop at WOT without losing bite. So I'm seeing how far it will go before it blows out and I get up to what looks like 5800-5900 (hard to tell because I was bouncing around a bit) rpm on the tach and run there for just a little bit, then I get a single beep and the RPM goes to 1000. I pulled the throttle back to idle and turned around and the engine is making a lot of smoke out of the exhaust port.

My common sense says this was the rev limiter.. No lights were on, and just beeped once, it's the first thing in the service manual. I shut down and restarted and the smoke cleared after a little bit and it ran fine the rest of the day.

So - Rev limiter kicks in and lowers my RPM, but throttle is still advanced to full, which means the oil pump is also advanced to full, which means extra oil, which means smoke.... right?

I won't do that again. I don't think I'm underpropped, just was trimming the motor too high.

-M

 

[whosmatt]

Re: TLDI rev limiter behavior

Nevermind. I used my service manual and the diagnostic mode to determine that it was an overheat condition.

Incidentally, the tach test showed 4800 instead of 5000, which means that I was probably bumping against the rev limiter as well and wasn't able to hear the beeping over the wind and the motor noise. That's a little perturbing, not to mention the fact that I was looking RIGHT AT THE TACHOMETER and wasn't able to see the temp light blinking or on in bright sunlight.

Hopefully nothing was damaged.

 

[pvanv]

Re: TLDI rev limiter behavior

Yep, you may have hit two warnings at the same time. Don't try to run at over 5850, or you risk triggering the over-rev ESG, to prevent damage to the motor. The over-rev warning beeper will only come on when the motor is over max RPM, and will clear itself as soon as the motor returns to normal RPM range. That's possibly the beep you heard.

However, the overheat ESG limiter will require clearing the trigger, by returning to idle, stopping the motor, and then restarting. Yes, if you had the throttle wide open while in the overheat ESG condition, you would deliver extra oil, which is the likely cause of your excess smoke.

You are probably OK. In the future, be careful to not trim so high that the water pump sucks air, and you should be fine.

 

[whosmatt]

Re: TLDI rev limiter behavior

Don't try to run at over 5850.

I was trying to run *at* 5850, or as close to it as possible

Is the 200 RPM discrepancy in my tach something that can be calibrated out?

 

[TOHATSU GURU]

Re: TLDI rev limiter behavior

Is it a Tohatsu tach?

 

[whosmatt]

Re: TLDI rev limiter behavior

Is it a Tohatsu tach?

Yes. The tach test points the needle at 4800

 

[pvanv]

Re: TLDI rev limiter behavior

You should be able to get a replacement tach under warranty from your dealer. Normally, those tachometers are very very accurate -- typically on spec within about 50 rpm. Internally, the tach could be recalibrated, but not necessarily something an owner should want or need to do in the field.

 

[whosmatt]

Re: TLDI rev limiter behavior

You should be able to get a replacement tach under warranty from your dealer. Normally, those tachometers are very very accurate -- typically on spec within about 50 rpm. Internally, the tach could be recalibrated, but not necessarily something an owner should want or need to do in the field.

Ok, thanks. I'll give them a call.

 

[TOHATSU GURU]

Re: TLDI rev limiter behavior

You might want to check that the right position was selected on the back of the tach.