Tell Tale Failure on my T9.9

[sherwindu]

Failure of the Tell Tale outlet is an old problem. As early as 2014 comments were that it was difficult to clean the tell tale water outlets. I cannot clean mine on my T9.9 with the usual wire probing or using pressure hoses. Can I run the engine without this tell tale connected? Any other thoughts on getting the tell tale to work short of disassembling the whole engine?
The engine now runs ok at low rpm while on my boat moored at my slip. Will it run ok at higher rpm without overheating?

[99yam40]

the TT is an indicator that the water pump is pumping water, if it is not indicating water flow, I would find out why

[DennisG01]

Agree with the above... also to add... that it IS simply an "indicator". If it (alone) is plugged, it will in no way compromise the engine. The question, of course, is... is that the only thing that is plugged?

[sherwindu]

I can only see where the tell tale hose attaches to the engine. It goes to a small box with two other hoses attached. Not sure what these other two hoses are for. I have been searching for some diagrams showing the cooling system and'/or an explanation of how it works. Right now, it is a blind item. If the impeller is working and pumping water back down the engine and into the river water, I cannot see this. Pulling off the lower unit is a problem while the engine is on the boat. I am going to try to run a pressure line at the tell tale attachment, but this time while the engine is running. I'm hoping for the best.

[DennisG01]

Could be clogged inside the box. Remove it and check it out. Just had the same thing on a Merc 20HP.

What makes it difficult to pull the lower unit off?

Run it on muffs - does it start to suck up the water? Do you see it then exiting the engine after running through it?

[99yam40]

disconnect the hose where it come out of the motor to see if water comes out of that when running.
what is that box you say it goes to?
trace the lines coming out of the box to see where they go to