1987 60hp 3cyl merc overheating
have checked water pickups ,have replaced water pump,checked water tube and grommets on both ends of water tube ,replaced powerhead gasket.removed exhaust cover and checked gaskets. this motor did not have any thermostat or relief valve ,and this was the first time the exhaust cover had been removed. removed head cover and checked for foreign material around cyls.-none . the pisser is pissing good and the hot alarm turns on at 4000 rpm, still pissin good the pressure gauge is reading 2-3 psi never goes above 3 psi. if ran at 3-3500 no alarm. w.o.t. timing is set right on. engine runs perfect otherwise.carbs are clean,and running fresh fuel. compression is 120 to 125 on all three. engine is on a 20 ft pontoon.HELP PLEASE!!!thank you.
have checked water pickups ,have replaced water pump,checked water tube and grommets on both ends of water tube ,replaced powerhead gasket.removed exhaust cover and checked gaskets. this motor did not have any thermostat or relief valve ,and this was the first time the exhaust cover had been removed. removed head cover and checked for foreign material around cyls.-none . the pisser is pissing good and the hot alarm turns on at 4000 rpm, still pissin good the pressure gauge is reading 2-3 psi never goes above 3 psi. if ran at 3-3500 no alarm. w.o.t. timing is set right on. engine runs perfect otherwise.carbs are clean,and running fresh fuel. compression is 120 to 125 on all three. engine is on a 20 ft pontoon.HELP PLEASE!!!thank you.