Hi! I have 2001 Bayliner with Mercruiser 4.3 190hp engine. My question(s) relate to rpm's. I recently changed the water pump (new housing assembly, gaskets, and impeller.) Haven?t had these replaced in recent memories, however the old impeller appeared to be in excellent condition with no rips or breaks in the vanes. Anyway I replaced it and put everything back together. Took it out on the water the other day and noticed that my idle RPM is only about 400. I believe this should be between 550 and 600. While idling for a few min the temp rose above its normal 175 to almost 200-225 and warning light and siren went off. I began moving the boat at a very low speed and the temp immediately went back to 175 degrees. The boat never stalled. I believe the engine is idling to low which is not allowing the boat to get the recommended amount of water thru the engine thus causing it to overheat. I was told that I should just increase the idle screw on the engine a little bit to get it to the normal range. Is that the appropriate solution? Should I be messing with the idle adjust?
On the flip side when WOT it only tops about 3400 RPMs reaching speeds of about 54-56mph. Engine sounds good and runs real smooth. Is it possible the tach is not working properly at higher RPMs? 3400 RPMs seems real low for this engine. Any assistance would be greatly appreciated. By the way my Prop is 14.5 X 19 and was replaced 2 years ago. Thanks
On the flip side when WOT it only tops about 3400 RPMs reaching speeds of about 54-56mph. Engine sounds good and runs real smooth. Is it possible the tach is not working properly at higher RPMs? 3400 RPMs seems real low for this engine. Any assistance would be greatly appreciated. By the way my Prop is 14.5 X 19 and was replaced 2 years ago. Thanks
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