View Full Version : 86 mercruiser 230
" i have a 22 four winns with a mercruiser 230 in it . the motor runs real good (besides the fact that its only a 305 and its a dog) but there is one problem with my engine , it only turns about 3800 rpms. i know the boat is very heavy but this motor should turn about 4500-5000 correct ? i was thinking maybe its a quadra-bog problem , but it doesnt seem to be starving , any help would be appreciated . thanks "
07-27-2001, 11:48 AM
" First thing first. On my boat, the tach gives an indication of where to expect the rpm to be when I get onto the plane. Does your tach have a line for green, yellow and red line? Cruise should be a bit below the orange line. Chances are, a little research on th einternet or through whatever manuals you might have for the boat and engine/drivetrain will give you what the manufacturer recommends. Will the boat plane at that rpm (3800)?
Because aboat is always pulling( like going up a steep hill in a car and never getting to the top) prop pitch is an integral part of getting the proper rpm range, or serious engine damage is possible.
If the boat has just starting acting like this: Have you added new equipment that may have changed the balance of the boat? Bigger batteries, porta potti etc. Does the engine seem to run any better or worse than before the problem started? Could it need a tune-up? Check the timing and especially the total advance. Check fuel pressure and delivery volume. Make sure the fuel filter is not even partially plugged. Check the fuel pump on the suction side, too.
If it's a new boat to you, or it's always been like this: you are going to have to go to a different pitch prop to get the engine into the correct rpm range.
Hope this helps.
04-18-2002, 12:45 AM
Try a smaller Prop..........
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