1986 Century Mirada 255 Merc 260 Alpha 1

[reimelss]

I dropped my prop last week, but was planning on replacing it anyhow. Since the boat has been in the water it has been very slow, carbs are cleaned, fuel filter is new, and I replaced it with a 17 degree pitched prop but the boat still seems very slow and is not getting on plane...at full throttle its at about 32-3400 rpms...my marine mechanic says it should be runnin about 44-4600 rpms. He also said it could be a problem in my gear ratio. But I need to know what the manufacture suggests what the gear ratio should be at...and he mentioned something about counting the teeth on the gears to figure it out. Does anyone know the proper gear ratio for this boat your boat or know where I might obtain that information.
Any help would be great.

 

[steelespike]

Re: 1986 Century Mirada 255 Merc 260 Alpha 1

"Dropped my prop"Do you mean in the water or dropped and bent?
It can be repaired easily.
Why would the gear ration be wrong was something changed.
A bit of a pain but I would think if you rotated the motor and counted the prop revolutions would give you an idea of the ratio.
It may have absorbed water,you might weigh it, dry weight is 4,200 lbs.
How is the compression.Is the throttle opening all the way,is the bottom
clean.Prop in good shape?Firing on all cylinders.Properly tuned and timed.