audible warning at full throtle

[charlieg593]

I recently took my boat out of storage last week. My brother and I went to the river and the motor ran fine with no problems. But today my wife and I went out and after about 10 minutes of running time an audible warning and the motor started running very badly. After idling for a few minutes it was ok. Then everytime after as we headed back in, a minute or 2 of top speed a warning and eratic engine after stopping it was ok. I have a 2005 50 tldi tohatsu. I,m thinking I have a water pump problem, or does anyone out there have or had a similar problem that was not a water pump problem. I,m planning on changing the impeller next week.
Thanks for any help

 

[pvanv]

Re: audible warning at full throtle

Before you go just changing parts at random... Was it an overheat alarm? Does the telltale stream look good? The TLDI has different alarms for different problems. I would diagnose the issue before just throwing parts at it.

 

[charlieg593]

Re: audible warning at full throtle

What other warnings does it have? This is my first motor of this type. The oil light didn't come on and the manual says oil warning would be 3 audible warnings every 30 seconds and light on tach would light up. This was a constant audible warning as long as motor was engaged in gear and would go off when in neutral idleing. after about 20 to 30 seconds of idle the buzzer would not go off when engaged and then could run at full throtle for about a mile before buzzer would sound again and engine slow down and run bad. The manual states that if engine over heats rpm's would drop to half then after 30 seconds drop by half again to protect the engine, thats why i thought it might be the water pump. I bought the boat 3 years ago used it once and then hurt my back and was not able to use again for 21/2 years until last week. The impeller had not been changed during any of that time.
I removed the lower unit today and impeller has cracks in it and the tip of one fin is missing but is not brittle, everything else looks fine. Do you think this could be the problem? Will be the weekend before I can test it again.
Thanks for any and all info.
Charlie-g593

 

[pvanv]

Re: audible warning at full throtle

Charlie,

It looks like you are headed in the right direction. If the impeller has any visual defects, it is time for a new one. Does the telltale have a strong stream of cool water?

The Tohatsu "limp in" mode will reduce top speed for a variety of problems, including an overheat condition, and should clear after a shutdown/restart. The TLDI tach should have 3 separate indicator lights, to show what fault area is being detected.

I'd get the pump back together (with new impeller) and see what happens.