'99 Johnson 115 overheating (still)

[rexicon]

Changed out t-stats and did the water pump kit/impeller also.

What do I look for next? If I use an IR temp gauge to check the accuracy of my console gauge - what do I point it at?

It idles fine and the gauge reads 140-150 at idle. As soon as I get on it it will start to climb steadily - I let it get as high as 190 before I backed off and I know it would have climbed to 220 or so then sounded the alarm (it did this before we changed out the t'stats and impeller). Once back on idle it cools down to 150 very quickly (less than a minute). Pee-trail is strong.

Any ideas greatly appreciated.

 

[Dhadley]

Re: '99 Johnson 115 overheating (still)

Point it at the area where the temp sender is. If you're sure the pump is working and the t-stats are OK you might consider the heads. If the heads have been off it's not unusual for someone to get a little aggressive with the RTV sealer.

We find that sometimes the heads get a scale-like build up internally. At that point you'll have to remove the heads and clean them out.