"Phil.... You have three alarm
"Phil.... You have three alarms on that engine. A steady constant beep is overheating. A beep every 20 seconds indicates that the oil level is down to 1/4 tank. A beep every other second indicates a faulty VRO, oil restriction, air in the oil line, etc.
I assume you have the steady constant beep warning, meaning overheating.
I do not know the exact temperture whereas the alarm is activated, but the thermostat is set to approximately 148°, and the alarm sounds off long before the engine is hot enough to do any damage.
The thermostat and the surrounding plastic housing are actually a two fold system in one. The thermostat of course is to regulate the temperture of the water, and the plastic housing is actually a water bypass valve. When the water pressure reaches a certain point, that plastic housing is forced off of the rubber seat which allows a excess of water to flow through the cooling passageways.
You don't actually say that you've changed the bypass valve external spring, but you sort of hint at it. If that spring isn't the actual OMC spring that's designed for that engine, and the external spring you're using is stronger, there's no way that bypass valve can operate properly, and that will restrict the water flow.
Pertaining to the water pump..... don't simply replace the impeller, replace the entire water pump assy as a kit. It cost a little more but it eliminates guess work.
So, bottom line.... (My opinion), Unless you've got a blown head gasket or clogged water passages, either the water bypass valve has a improper spring, or the water pump was installed improperly.
Gasket Sealer (the type that comes in a can that has a small brush in its screw off cap) must be used on any gasket, and "Sealer 1000" or "OMC Adhesive" (same substance) must be used on any metal to metal or metal to plastic surface (such as impeller hsg to plate) to eliminate air leaks. Sealer 1000 may also be found in other brand names such as "Boat Armor" but the name of Sealer 1000 will always be mentioned on the tube. Good Luck......
Joe
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