yamaha 115 overheating

[Vitamin Sea]

I have a 115 yamaha thats overheating w/buzzer under a load at 1500-2500 rpm's. I've changed water pump & thermostats with no improvement at all what any suggestion would be greatly appreciated:[

 

[Grayhorse]

Re: yamaha 115 overheating

No experience with that particular engine, but have a Yamaha 70 with similar problem. Changed impeller, thermostat, etc. Low water pressure was the major issue. When checked with a gauge, maxed out at 4 PSI. Found the upper and lower water tube grommets/seals to be defective, leaking water pump output before it even reached the powerhead......Another issue with some Yamaha outboards was the plastic water inlet screen on the lower unit being somewhat bowed, disrupting the suction ability. Replaced with the updated type. ONLY noticed at higher speeds.......

 

[Vitamin Sea]

Re: yamaha 115 overheating

I will check both of those and check back with results . I figured it has to be some restriction or a leak within system just wanted to know if there is anything else i could check before I battled removing heads to check for blockage's<br />Greg

 

[Vitamin Sea]

Re: yamaha 115 overheating

still overheating is there anything else that could set this alarm off ,the model is c115

 

[seasilly]

Re: yamaha 115 overheating

i have an 84 yam 115 v4 and it was doing the same thing only at full throttle last year...i changed the thermostats,cleaned inside the therom cavities...lots of salt and gunk....and put new impeller...cleaned out the whole lower unit....no problem now at full throttle....

 

[bonitoman]

Re: yamaha 115 overheating

Pull your heads and clean the passages. Pull your water jackets and replace the heads with new water jackets. Scrape the cylinder heads and scrape everything clean

 

[cousinabe]

Re: yamaha 115 overheating

could it be the poppet valve has debris in it.

 

[Ray Neudecker]

Re: yamaha 115 overheating

The poppet valve would definitely be on the list of items to check and clean. Trash in it is a very common cause of the condition.