1998 Yamaha 115 saltwater series

Kickass

Cadet
Joined
Oct 17, 2007
Messages
16
Ok,
The temperature sensor STILL goes off,,,,,
Here's the deal, and what I have done so far.
1. Replaced impellor, Tech said waterpump was fine and did not replace, strong pee stream.
2. Serviced lower unit.
3. Tech opened ONE head to check water jackets, said it's very clean and nice, whoever owned it before me took care of it.
4. Changed Thermostats.
5. Changed TEmp Sensors

After changing the temp sensors things were fine, but realised the motor was over propped.
I had Stiletto 13x21, only getting to 4400 RPM @ WOT, it should be 5500, so got an aluminum OEM Yam Prop 13X17, took it out on the lake and got up to 5600, so that's the right prop.
The setup I have is a 1998 Key West Stealth Flats Boat 17'6"
1998 Yamaha 115 Saltwater Series TLRS
boat weighs 1080
motor 380
blah blah,,,
it's about 2000 lbs with half a tank including batteries and me.
Oil is good, it's not the oil sensor going off, the Overheat alarm goes off, and the arrow flashes on my digital gauages that it's overheating, and powers down, I can sit for a minute a two and then it's fine, run it up and go again.
THe intakes are clean on the lower unit, and like I said the pee stream is strong.
I've even disconeccted it, pee line inside cover, and ran a wire through to make sure there are no obstructions

It did not overheat when the motor was overpropped though, which I thought interesting.
I need some help guys!
Thanks,
Charles
 

Ray Neudecker

Lieutenant Commander
Joined
May 25, 2004
Messages
1,656
Re: 1998 Yamaha 115 saltwater series

Could be a good time to check the other head. You can get blockages without corrosion. Gravel is something I find in them as well as impellor parts and wood.
 

Kickass

Cadet
Joined
Oct 17, 2007
Messages
16
Re: 1998 Yamaha 115 saltwater series

Thanks for your response Ray!
Do you think the motor might be too high on plane and not get enough water?
I haven't checked but will tomorrow, just a thought.
 

Ray Neudecker

Lieutenant Commander
Joined
May 25, 2004
Messages
1,656
Re: 1998 Yamaha 115 saltwater series

That is possible. A water pressure guage would be a very useful trouble shooting tool.
 
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