Re: mercruiser 470 & 488
Slow down there Lynn boy... Too many questions not all relate to original Q. As for a 190 temp over a more normal 140 temp... He could have swapped his thermostat to a higher temp range. Your 140 thermo is what the factory suggests. Just because the engine is FW cooled, the higher temp (thermo) will cause the raw water to raise up in temp. I hear that salt separates at just above 160 I think... He will have a better chance to have (elbow) salt build up than you.
Oil on the fill stick (if factory) is where you want to settle. The sender may say "high" but that is most likely oil pressure not level. Not likely anything is going bad that I could tell you about w/o looking.
OK, so you are low on coolant but it's not sucking from the reservoir? Is the oil level growing or changing color? When running after its warm (thermo open) do you see air bubbles coming up with greater RPMs? Maybe your coolant is swapping sides- going into raw water. Why it isn't sucking off the reservoir is a vacuum issue. Maybe a pressure cap or a leaky hose issue. Pressure testing will tell you.
