Merc1150 in-line 6 cooling issues

[Edjano14]

Just picked up this engine recently, after repairing lower unit and installing new impeller and housing and reinstalling lower unit I am having issues with the cooling. No water through telltale but not blocked, a healthy amount through the exhaust ports and after 2 minutes at idle it is still cold but the engine feels hot. Could this be a thermostat issue, misaligned water pick up tube when installing lower unit or???

 

[Faztbullet]

You have no t-stat.....is exhaust side plate hot or cold?

 

[Edjano14]

Not super hot, After 90 seconds I could keep my hand on it for a couple of seconds. Exhaust water was still cold.
thanks

 

[jimmbo]

Is water coming out of the horizontal slots just above the Anti-ventilation Plate? The prop?

What condition was the old impeller?

Those engines have simple cooling system, and water pretty much has to go thru the block first. The flow pattern i the block is very simple

Water enters the bottom of the block, exits at the top into the exhaust cover, from there it goes to fill the midsection to isolate the exhaust tube. Some is discharged thru the idle reliefs and into the exhaust. Once the exhaust tube is isolated, the water is dumped out of the engine thru the slots above the AV Plate

 

[Edjano14]

I have been running in a garbage can full of water, will have to put it on the muffs right? Old impeller was in fair to poor condition, previous owner said he had no issues with overheating or telltale discharge.
Thanks I will put it on muffs tomorrow.

 

[Faztbullet]

If its cooling correctly that exhaust cover will be the same temp as water in trash can...other words it should stay cool

 

[jimmbo]

It will be a warmer than the water in tank, the water passing through it has absorbed heat from the engine

 

[Faztbullet]

No as water goes thru exhaust plate cover first before entering engine block....

 

[Edjano14]

Thanks for the input, I am going to drop the lower unit and reattach tomorrow, hopefully the water pickup tube is just not aligned correctly If that is not it any other ideas on no water through the telltale?