IT HAPPENED AGAIN "BUT"

[MSCLE]

OK I HAD THE SAME PROBLEMS TODAY(HORN GOING OFF),BUT TODAY THE WATER FELT HOT!!!!!!!THE MOTOR ALARMED SEVERAL TIMES ALL BETWEEN 4OOO AND 55OO RPMS......I HELD IT AT 7200 RPMS FOR QUITE SOME TIME......IT RAN FINE.....NEVER ALARMED,THINKING THE MOTOR RUNS COOLER AT THESE RPMS.....THURSDAY I AM BRINGING IT IN TO THE SHOP TO GET LOOKED.....IF I HAVE TIME I WILL GET IT HOOKED TO THE DDT TOMORROW AND POST THE READINGS.....MAYBE THEN WE CAN TRY TO FIGURE THIS OUT.......MY NEXT STEP IS TO TIE A 50 FT ROPE TO IT AND USE IT AS AN ANCHOR........PROBLEMS...ALARMING BETWEEN 4000 AND 5500 RPMS......FELT OUTFLOW FROM TATTLE TAILS.....WATER WAS HOT FOR THE FIRST TIME BUT ONLY ONCE......ALL OTHER ALARMS WATER WASN'T HOT TO TOUCH.........COULD THIS BE A FUEL CURVE THING,WATER PRESSURE IS EXCELLENT!!!!!!THANKS....SCOTT

[us1]

If the motor were really over heating the water you describe as HOT would be unbelievably scalding to the touch, almost boiling. I still think it sounds like a short in the wiring.

[steve]

Scott. I have the original DDT readings and there was not even 1 sec of overheat. Do you have access to a Merc water temp gauge? I think it could be a bad wiring harness or a loose wire somewhere but I don't think that could cause both the sender for the alarm AND the ECU sender to read bad. It would be rare for both to be shorted etc. I think you have a water availability problem that you are overlooking and at high rpm the pump is finally catching up. Possibly not enough water is getting from the nosecone to the pump or the pump is shot and the pressure at speed is helping. The motor has never run hot, ever and I've had a Sportmaster AND a Fleetmaster (200) with a bob's on the motor. Its not the ECU making the motor run hot either. That motor screamed ever since I had it and the plugs and pistons looked great too. How does she run on your boat? Start at the nosecone and work your way up. Check it with a seperate Temp gauge and sender. Also a good machine shop will have wax pencils that melt at specific temps or little buttons that pop out when a head or block gets too hot. I can get you some if you can't find these. They will also help you determine whats what. Try a gauge to verify but I am guessing water pump or nosecone. Take care and email me sometime !! Steve

[AlaskaStreamin]

Scott,

My 200 pissed like a race horse till the temp guage hit the red. The horn would go off and steam would come out of the tell tale hose. I FINALLY traced it to a waterpump impeller. I had changed it three months earlier. The rubber peeled off the hub and was all wadded up. I refused to agree with everyone that it could be the impeller because it was peeing. Wish I would have looked before three months and $100.00+ in gaskets (two sets of head and a base). Good luck. I feel for ya. Keep us posted.