Engine cooling properly in the lake, overheating with muffs!

[OldSkoolFloater]

This engine runs super cool at the lake. Yet, with the muffs on it, nothing is circulating and overheats quickley. I know this sounds like the opposite of most problems, but what would cause this? The thermostat has NOT been changed, the head gaskets have been and the deflectors are in new shape. Impeller changed also.

 

[Bobbywolf]

What size and year of outboard? I have had several in the past that did not do real well on muffs. Little or no tell-tale stream. Put it in the lake, or in a barrel, and it works great.

 

[Scott Danforth]

Do you have the hose in full? There should be spray coming from the muffs until the motor is started

 

[racerone]

Some pressurized water has a lot more air than lake water.----This comes out of solution and may form an air pocket.----Or open your valve on the hose to wide open.

 

[OldSkoolFloater]

1977 Johnson 115HP. Water all the way on and spraying out the sides with the muff attached.

Sorry I didn't respond quicker....I didn't hit the ol computer refresher button...