overheat alarm

[tomryan]

after replacing the wiring harness, i am now getting the overheat alarm at idle. the pisser shows flow, but it is marginal at idle.

BEFORE i split the foot and replace the impeller, should i dismantle the check valve and check for an obstruction. the manual is lacking in the description of the cooling flow and passages.

[<Hamfisted>]

What kind of motor? If it's a V-6 make sure you use the type flush muffs that feed from both sides of the lower unit water intake, i.e. through both muff cups. How old is the waterpump? If it's more than two years old I would replace it. Have you pulled the thermostats and checked them for mineral buildups or debris. The pressure relief valve is prone to clogging if you use a nosecone low water pickup on the lower unit but other than that it shouldn't be a problem. After many years (4+...) use in saltwater you might get a mineral buildup under the rubber seal of the valve and it will cause the valve to get seized up possibly in the open position and cost you water pressure. Do you have a water pressure gauge on the motor? If the tell-tale stream looks weak to you it probably is. You're most likely needing a new waterpump anyway. If you don't have one already go to www.YamahaPubs.com and order yourself a factory service manual. Good luck.


Mike