98 mercruiser 5.0 possibly overheating

[Gnmike87]

Bought ran great last year, temp guage usually stays around 140 when running. First start-up this year and it’s staying at 120, risers are warm to the touch (no IR gun yet) but not burning hot. Coolant hoses are pretty hot to the touch. There is plenty of water coming out of the transom. The impeller was replaced at the beginning of last season. I just replaced the thermostat hoping that was it, but no change. Is the amount of steam I am seeing normal? Where should I shoot the temps with an IR gun to verify? What should temps be approximately?

 

[Gnmike87]

To add: if that amount of steam is normal, there might not be a problem, I am just a bit nervous. I don’t remember it being like that last year. I am also not sure on the accuracy of my stock gauges. If I shoot it with an IR fun where the temp sensors are, I’m assuming they shouldn’t be more than 160.

 

[Scott Danforth]

Back flush your system.

Check the impeller

 

[tpenfield]

If the amount of water coming out of the outdrive (on land) seems normal, check the thermostat housing for corrosion/blockage, if other things fail to resolve the problem. Also, check the thermostat for proper operation.

Much of the incoming water to the engine would go to the exhaust risers if it was being blocked from going into the engine. Therefore the output flow may look normal at the outdrive.

 

[04fxdwgi25]

Doesn't look bad at all, to me. What was the outside air temperature when you running it on the hose?

If it is cool outside, perfectly normal.

 

[Scott06]

Looks fine aka normal. If you can put your hands on the exhaust parts for a moment or too you are fine

 

[Gnmike87]

Looks fine aka normal. If you can put your hands on the exhaust parts for a moment or too you are fine

Doesn't look bad at all, to me. What was the outside air temperature when you running it on the hose?

If it is cool outside, perfectly normal.

Temp was around 80. I’m going to bring an IR gun home today and take some readings.