mercruiser 3.0l with incorrect sterndrive gearing help!

[lawson]

Hi everone i have bought my first boat...it is a flecther faro about 1989 with a mercruiser 3.0l engine and a alpha 1 gen 1 sterndrive...its is 19ft long and 7ft wide..the weight is 660kg or 1455lbs ex engine...it is a sports cruser cuddy with a 25 percent deep vee hull....the guy i bought it from had it on a river...he took me out on a nice day it sounded lovly and he slowly took me up the river...i asked him the top speed he said it should be about 30-35mph..however as he was on the river and we where in a speed limit he would ont open it up..anyhow i bought the boat...1 week later i went up to see the boat as it was about an hours drive from my house and to have a ride in it and to arrange having it pulled out the following weekend to have it bought home and put into a boat mechanic for a service in my area...my first and only ride in my new boat was not that good...i took it up river out of the speed limit and opened it up..at this time i did not even know what the trim button did so i did not touch it..lol...i just pushed the lever fully forward...the nose went up in the air and the back went down and i was doing about 9mph flat out according to the gps fishfinder..i though dam its slow...the neaxt weekend it was lifted out the water and the guy said it was covered in mud and barnacles underneath..he had jet washed it and i flated it down and antifouled it...now it is with the boat mechanic being serviced ready for the summer...he has done the engine and has started on the stren drive...once he stared that he rang me and told me that when he took the strendrive off he noticed it said on the inner casing...it said starboard...he then told me that he thought maybe the sterndrive had come off a boat with 2 engines and that he had counted the teeth in the upper drive of the sterndrive and that the gearing was from a 4.3l engine....and for him to fit the correct gear for a 3.0l would cost a fairbit of money..so my question is what differnce would leaving the the 4.3l gearing make to my boat??...would it...damage my engine?...be slow?...not get on the plane?...not pull?...etc...i dont mind spending the money on haveing the correct gear fitted..however i just wanted to know how much differnce it would be to the boat leaving the 4.3l gearing in the sterndrive???...what i would like to use my boat for would be this...sometimes to pull skiers...maybe get some toys and pull them...and on other days just to cruse about slow and do some fishing....any advice would be much appreciated...thx you all

 

[achris]

Re: mercruiser 3.0l with incorrect sterndrive gearing help!

The correct ratio for a 3.0l is 1.98:1. Some models of 4.3l came with 1.84:1 and some came with 1.65:1. You need to find out which you have.

If it's the 1.84:1 then I would just fit the next smaller prop. No biggy.

If it's the 1.65:1 you may have a problem finding a prop small enough to allow the engine to reach max revs, in which case you would be best advised to either change the gears, or buy a top box with the right ratio. I believe SEI make good gear at a very reasonable price, and you'd have the old top box to sell second hand.

Just my thoughts.

One last thing. Regardless of what you do, just make sure that you put a smaller prop (2" less than your 'cruising' prop) on when you pull toys and skiers, or you will damage your engine.

Chris...........

 

[lawson]

Re: mercruiser 3.0l with incorrect sterndrive gearing help!

Hi guys thx for your advice...the machinic has called me this afternoon...he said he has striped down the drive and that its in good condition..apart being geared wrong...he also said the prop is a smaller than should be on a 3.0l...i said well lets just go ahead and fit the correct gears...however he feels the guys that fitted this strendrive may have sorted it with a smaller prop pitch etc and would like to test it on the water first...he told me that if we found it to be to slow he would fit the correct gear and not charge me for putting it back together then restipping it only for the gasket and of cousre i will have to pay for the new gear and fitting charge....not to sure if i can afford a new strendrive as u also said...plus i live in the uk and i am not sure if they sell them here...the ones that u pointed out...but thx guys for your help....i will get there in the end i hope...