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mercruiser gear ratio

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spencer 58

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hi guys new to the forum and mercruiser also.previous volvo owner.purchased a 1992 5.0 alpha 1gen2 and am not sure of gear ratio or how to tell.any advice really appeciated.thank you/jim
 
Most Small V8's use 1.50 : 1 Or 1.47 : 1. ratio's.

On the passenger side of drive (near top of drive) where the decal is, the serial number and ratio are stamped into the casting under the decal.

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thank you for the reply.unfortunately i cant see anything there as too much corrosion.thank you again,i will try the pencil trick though.brand new to me and actually just got it back to my place to start working onit
 
spencer 58 said:
hi guys new to the forum and mercruiser also.previous volvo owner.purchased a 1992 5.0 alpha 1gen2 and am not sure of gear ratio or how to tell.any advice really appeciated.thank you/jim
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Ayuh,..... Welcome Aboard,...... If this boat is a runabout, say 23" or less, Jack is correct, it'll be a 1.5:1,.....
If it's a big ole cruiser, it could well be a 1.65:1,.....
 
hi guys,sorry for not getting back sooner got locked out password issues?.anyway the boat is a 2452 bayliner classic{i know} but i got the boat for the cost of the merc 15 efi electric start.just a project that does not involve working on houses.the hull and stringers are in good shape interior pristine for a old boat 1992.as stated had a 78 bay saratoga i totally rebuilt/transom /stringers /interior.put 1200 hours onthe boat ,never would have got another boat but lost the saratoga to a house fire.so just here to get some help when needed and offer any advice i can give/no bs will not respond without experience.live in the pnw and have been from gig harbor all the way to desolation sound .live on whidbey island north of seattle.thank you for your time and hopefully i don't become a pain in your ass/too many questions.retired so not a problem getting the boat in the water tommow .thanks again/jim
 
Wasn't there a data placard on the rain bonnet over the carb & distributor also?
You could always take the top cover off & count the teeth. Only 4 bolts & an o-ring.
 
Due to the size of the boat, the original suggestion of 1.50:1 ratio may not be correct. The easier way to determine the ration is to pull the drive off boat, Put in forward gear by turning shift lever sticking up from lower part of drive fully clockwise,
Rotate the u-joint drive shaft and determine the rotation amount of the propeller. Put a mark on the u-joint drive shaft and prop so you can see the amount of rotation clearly.

1.5 rotation of drive shaft and 1 rotation of prop would equal 1.50 :1
1 and almost 3/4 turn of Ujoint drive shaft and 1 rotation of prop would equal 1.65:1
2 turns of u-joint drive shaft and 1 turn of prop would equal 2.0:1

As the boat is 24 ft long there is a possibility the Lower unit gear ratio may be different from most and could make the drive total ratio 2:1
 
spencer 58 said:
hi guys new to the forum and mercruiser also.previous volvo owner.purchased a 1992 5.0 alpha 1gen2 and am not sure of gear ratio or how to tell.any advice really appeciated.thank you/jim
Click to expand...
If the engine has a plastic cover over the flame arrestor, it may also have a label with engine & drive serial numbers- if you have those (they may also be on your title), you can look on the Mercury site for info. They changed to a simple flame arrestor at some point, but this info was on that, too- if the flame arrestor is just plain Aluminum, any cover or shroud may have been discarded.

If the engine/drive are original to the boat, you may be able to contact the manufacturer of the boat- find the Hull ID on the transom and ask for build specs. That is, if they're still in business.
 
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