Mercruiser 3 ltr Thermostat

[Bigplumbs]

I went out today for the second time in my new to me boat. It is a Fletcher 19 gts with a 2 year old Mercruiser 3 ltr by repower marine. I am not used to temps on these engines so here is what I was getting.

Cruising along at 5 knots at about 1200 rpm it was at the bottom of the scale at about 100 - 110 degrees f (Water is cold at the moment)
Flat out after a while about 4500 rpm it got up to 175 - 180 degrees F
At about 2000 rpm it was about 140 degrees f.

Does this sound normal. I was a bit worried about the temp flat out as it was getting nearish to the red line.

Impeller pumps ok but I am not sure about the thermostat

Any advice would be helpful

Regards

Dennis

 

[dpb]

I am sure that when i had one of these it ran at a fairly steady temperature. 170 sounds about right. Maybe stat stuck open?