Hi I have a 2004 Optimax 115 1.5l OT869845.
Which has an overcooling issue, when I put her in for the season she temps when straight up to 143f as normal the would drop to 90 once under way. Then all a week it won't make normal temps at idle only around 42, had a new water pump and I have since replaced thermostat, and poppet diaphragm and the idle temp went back to normal, but after the first run when returning to idle it is stuck any where between 100-115.
Water pressure at idle is varies between 4 - 4.5 psi straight after installing the new thermostat and poppet diaphragm whe idle pressure was just over 5psi but has droped slightly it was too rough for a wide open throttle run but around 4000 rpm it was just over 10psi.
Any ideas I was wondering if I should replace the popet valve spring but not sure if that would help or not.
TIA