Yamaha 5.7 Temp Fluctutation

dolemite76

Recruit
Joined
May 9, 2012
Messages
2
I have a 1995 Chaparral 2130 SS with a 5.7L Yamaha I/O that just had the impeller replaced. At high speed the temp gauge reads at normal but when I pull it into idle after running high speed the gauge maxes slowly drops back down to normal temperature over a period of 5 or so minutes.

I'm new to this boat but I've never experienced this with other boats I've owned.

Thanks for any input.
 

Capt Ken

Commander
Joined
Jul 30, 2002
Messages
2,269
Re: Yamaha 5.7 Temp Fluctutation

Not a strange occurance. Your engine has built up a lot of heat and when you slow down the water flow also slows down removing the heat slower. I've seen this on just about any brand of engine. If you slow it down to about 1000 rpms for a minute before going to idle, it will not max out the temp gauge
 

dolemite76

Recruit
Joined
May 9, 2012
Messages
2
Re: Yamaha 5.7 Temp Fluctutation

Good deal, that's what I was hoping. I had another guy tell me the same thing. I didn't remember it fluctuating this much on my 4.3L. Thanks for easing my worries.
 

Capt Ken

Commander
Joined
Jul 30, 2002
Messages
2,269
Re: Yamaha 5.7 Temp Fluctutation

Just about every engine will spike the temp if you take it down too fast and at idle it don't pump a whole lot of water. Bump it up a bit off idle and the water flow greatly increases. Also how low is the engine idling? You should be around 750-800 in gear. I've had the YEMS models idle as low as 450 in gear but that's because the computer will allow it to and keep the engine smooth.
 
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