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-   -   mariah 182 shabah incorect gear ratio? (http://www.mariahownersclub.com/forum/prop-talk/7085-mariah-182-shabah-incorect-gear-ratio.html)

roadrash 07-01-2012 11:00 PM

mariah 182 shabah incorect gear ratio?
 
Hi i have a mariah 182 shabah that last year i decided to replace
the 3.0 ltr engine with a reconditiond 4.3 mpi as the 3.0 struggled
to pull a mono skier out deep water start , whe i replaced the engine
i also upgraded the gearbox from a 181:1 ratio to a 2.0:1 as i thought
that this is what i needed to do.
problem is, i still feel it takes too long to come on the plane while pulling
skiers out. i have tried different props 19 pitch and 21 pitch both are high
fives so should be plenty of torque.
could anyone advise if this is the correct ratio gearbox to use?
Should i have stayed with the 181:1 ratio?
the leg is trimmed all way in. tried ballast at the bow using fatsacs
adding up to 400 lbs up front and no passangers in the rear still lots of
bow lift . last resort i fitted bennet trim tabs but still not much improvement.
any help would be greatly apreciated
regards phil.

DCB_MINDED 07-02-2012 02:27 AM

Re: mariah 182 shabah incorect gear ratio?
 
Have you actually verified that the outrdrive is trimming all the way down? sometimes they don't go down all the way....

roadrash 07-02-2012 07:50 AM

Re: mariah 182 shabah incorect gear ratio?
 
it certainly looks like the hydraulic rams are bottoming out as the pump does not turn off when at the bottom and sounds under load when at the bottom .
regards phil

mikeyt 07-02-2012 02:50 PM

Re: mariah 182 shabah incorect gear ratio?
 
According to the guides i've seen.....a 4.3mpi efi should be running a 1.62:1 gear ratio and a carbureted 4.3 should be at 1.81:1 But then that same guide shows the 3.0 as standard with a 2.00:1 gear ratio so its sound like you've gone in the wrong direction with your ratio change.

ColoradoDiablo 07-02-2012 03:09 PM

Re: mariah 182 shabah incorect gear ratio?
 
What Mikey said :)
I did the same thing when I went from a 2.3L to a 4.3 in one of my old boats. Definately need to go to the 1.62 ratio as Mikey states.

Larry

roadrash 07-02-2012 10:49 PM

Re: mariah 182 shabah incorect gear ratio?
 
Hi thanks very much for the input guys.
I got the boat out of the water this evening to check the angle of the cavitation plate against the hull to make
Sure at its lowest trim there was a negative angle which there is . Double checked the ratio and I have to say I was wrong
The ratio I have is 181:1 and the old one I took off the 3.0ltr was a 2.0:1 howeve is your saying I need the 1.62:1 should I change it as what I heard is that if propped correctly shoul be ok . I have propped ok as with a 19 pitch hits rev limiter of 5000 rpm at about 42 mph. With the 21 pich on which I have stuck with does 50 mph and max revs are about 4800 rpm both are high five props. Took it out for a spin when I dropped it back in the water with just me in the boat and 3/4 full fuel tank and came on the plane in seconds perfect . Any input on this? Regards and thanks phil


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