running temp of 98 25hp merc

[rosco pico]

does anyone know the correct running temp of a 1998 25hp mercury at sea temp of 23 degrees c. prefer temp at telltale if possible.

 

[emckelvy]

Re: running temp of 98 25hp merc

Temp at the telltale doesn't mean much.

The thermostat, if this is a 2-stroke twin, is approx 120 deg F.

When warmed to full operating temperature, the exhaust manifold on the side of the powerhead should be relatively cool or just lukewarm to the touch. The block and head will be at temperature. As long as you can lay your hand on the block/head and can hold it there comfortably for 5-10 seconds or more, you're about right. And if the exhaust manifold is hot, definitely wayyyyy too hot.

If you lay your hand on the powerhead and have to immediately remove 'cause it's that hot, it's definitely Too Hot!

Telltale on these typically feels quite warm but that's just the way they're are built. Block & cyl head temperatures are the most important.

HTH............ed

 

[rosco pico]

Re: running temp of 98 25hp merc

thanks for that. powerhead not too hot. telltale just got little hot at lower speeds. put new impellor in and found the old one was a little curled up. should fix it. going to give her a test run this morning.