i have a 1992 yamaha 70 HP which overheats when idiling,or trolling.it always has an indicator stream,which feels cool.Have checked the thermostat and it is ok.let the engine set for a few and rev it up it is ok until i slow it down and takes 10 or 15 minutes and the warning goes off again.Think it may be the impeller,but would like to know if there is something else it could be,before i tear into it. thanks in advance for any info.
