Yamaha 70TLRB

[<Mark>]

What can cause over heating on a 70hp two stroke at idle speed, in gear? The water pump has been completely rebuilt, including a new pump housing. Water jacket removed and cleaned. Thermostat replaced. Blew compressed air through water lines and hoses.

Any ideas would be much appreciated.

[<boats.net>]

The 70HP has an high volumn low pressure system, it does take a lot of water to keep it cool, small problem in water pump or in cooling passages can cause it to overheat