Pontoon Boat & Deck Boat Forum

Hi all,

I have a 2016 Coach 23C tri-toon with Honda BF150 (just one year old and 21 total operating hours). I was out boating yesterday and noticed when wide open throttle, my NMEA coolant temp was up to around 205 degrees F. When I stopped and idled, it was around 168 degrees F. Are these normal temps? They seem high. I didn't receive any alarms, but just concerned.

I've never owned a Honda, but it sounds normal to me. Both my Verado and Yamaha did exactly the same thing. The T-stats opened up at 195 on the Verado and cycled open-closed. Temp always ran about 200 when running hard. Then dropped down at idle, until the T-stats closed. I would check with a Honda dealer, just to confirm this is how it should be on yours.

My Mercury runs around 136 on my smart craft gauge unless theres weeds on the lower unit, then it goes up to around 160-170..
It once hit 203 on the hose and my hot alarm sounded.
I would keep checking....

Thanks everyone for the replies. I checked with dealer and they said it was normal for the temps to be in this range.

seems a bit high to me, My DF140 idles ~160*f and hits the mid 180's max on long WOT runs. With straight water it will start to turn to steam at 212*f which would create air pockets (BAD). If it is truly 205* you don't have much of a safety barrier. Just about every outboard I've owned has around a 170-180* thermostat. With an unlimited supply of cooling water from the lake shouldn't run much more than ~5* above the thermostat unless you have a bad water pump, bad thermostat, or blockage of some kind. Another possibility is the engine is mounted too high and your sucking some air at higher speeds.

[quote="CajunCoach23"]Thanks everyone for the replies. I checked with dealer and they said it was normal for the temps to be in this range.[/quote]
I'm sure you know this, but That would be the last people I'd listen to.