Wrong gear ratio?? What else? long...

[jello1973]

Hello...
I recently purchased a '94 Caravelle, 17ft bowrider w/ "135hp" 3.0 mercruiser w/an Alpha1. It's very obvious that the lower unit has been changed, just trust me.
The motor, having been checked out by local marina, is in great condition. It had a 21 pitch prop and I could only turn 2700-2800 rpm's @wot! So, I buy a 14 1/2 x17 pitch which was recommended by seemingly everyone.. NOW, i get 2800-2900 RPM's @wot!?!?
In neutral the boat revs/idles fine. and even under load it runs fine. It just can't pull the rpms... Seems like it's working very hard. Seems to me the whole outdrive, prop and all must've came off a bigger more powerful boat.
Here's my question... Can someone tell me the optimal/factory gear ratio this boat should have? Though I don't know what gears are in it now, not yet, I will probably pull it off today and find out.
I do thank you very much for any help!

Oh no! I posted in the wrong thread... I'm so sorry!

 

[donnymac]

Re: Wrong gear ratio?? What else? long...

That pitch change should have netted you a 1000 rpm(+ or - a couple hundred) There will be more people on this forum with far more knowledge than I. But I'm thinking even if your motor was down to a 100 horse you should have got a bigger jump in rpms with that pitch change. But stick with your plan about findiing out the ratio in the leg. I'm leaning towards the motor though.

 

[wca_tim]

Re: Wrong gear ratio?? What else? long...

The gear ratio difference is in the uper gear box. The lower halves are the same for all intensive purposes. If you stand behind the drive, the gear ratio should be stamped on the upper half of the outdrive, on the left forward side of the upper outdrive housing, just below the second stud / nut that holds the drive. If it says 1.98 and you're still thinking the inner gears may have been changed, you can take the cap off the upper gear housing with a 12 point 3/8 socket, count the teeth on the gears and look up what they are for the various gear ratios. If you do tha latter, be sure to properly retorque the bolts on the upper housing to ca. 20 ft-lbs (My book says 17-23). after you figure that out you'll know whether to worry about the engine power or the drive ratio. I would be inclined to agree with the poster above but make sure on the drive gear ratio first...

 

[Coors]

Re: Wrong gear ratio?? What else? long...

check it with a remote tach.
http://forums.iboats.com/showthread.php?t=167561

 

[jello1973]

Re: Wrong gear ratio?? What else? long...

Okay, tomorrow I will be checking the gear ratio. It isn't "stamped" anywhere on the housing though so I will need to open it up I guess.
I know of a mech. that says he'll open it up and look at it, though he wants to charge me an hour labor to do it.
I'm a little reluctant to get into these things on my own since I'm "green", yet I don't want to get robbed either.
I'm okay with spending necessary money for what I can't/should'nt do myself.
I do have SOME mech. skills, but I'm nervous since I don't have a circle of friends with knowledge of boats (except here)
One guy told me that the whole unit may have come off a v6 or a v8 and if it did, according to him, it's more dersirable to people than the four banger unit. If this is true and if someone has what I need, would an even swap be fair?
Thanks so much for having patience for my ignorance, it's a learning curve...

 

[wca_tim]

Re: Wrong gear ratio?? What else? long...

Okay, tomorrow I will be checking the gear ratio. It isn't "stamped" anywhere on the housing though so I will need to open it up I guess.
I know of a mech. that says he'll open it up and look at it, though he wants to charge me an hour labor to do it.
I'm a little reluctant to get into these things on my own since I'm "green", yet I don't want to get robbed either.
I'm okay with spending necessary money for what I can't/should'nt do myself.
I do have SOME mech. skills, but I'm nervous since I don't have a circle of friends with knowledge of boats (except here)
One guy told me that the whole unit may have come off a v6 or a v8 and if it did, according to him, it's more dersirable to people than the four banger unit. If this is true and if someone has what I need, would an even swap be fair?
Thanks so much for having patience for my ignorance, it's a learning curve...

I hear you on worrying about getting into it yourself... in terms of checking the upper gear box, it's only 4 bolts to remove the cover off the top of the top of the upper housing, they look a little funny because they take a 12 point 3/8 socket. Nothing will pop out at you, but it is a good idea to torque them to the propper spec when you put it back together / before you use it. Look real close at the housing where I was talking about.. It can be hard to see if it's been painted over, etc... and will be something like 1.98 r 1.84 r, 1.65r, or 1.50r... I would consider buying a manual and doing some searches and reading on here. you may decide you don't want to mess with it, but then again, you may decide it doesn't look so bad...

on even trade, you're thinking the right direction, the problem is with a used drive from a 'stranger" you've got no idea what you're getting. Might be more economical to purchase a new upper half or even whole drive from sei if the gear ratio is indeed wrong. I'm actually going to be surprised if it is off... how fast were you going with the rpms you list above? especially if you have gps speeds or an idea of how far your spedometer is off...

 

[nailem]

Re: Wrong gear ratio?? What else? long...

how would he or i know what gear ratio should be in the boat?

 

[TilliamWe]

Re: Wrong gear ratio?? What else? long...

how would he or i know what gear ratio should be in the boat?

I am fairly certain that all 3.0s at anything but high altitude are close to a 2.0 to 1 ratio drive.

Jello, the bottom of the boat is not really dirty is it? I also suspect that you are down on power. Among other things, check for a restriction in the exhaust, if the motor is not actually "misfiring" at all.

 

[tommays]

Re: Wrong gear ratio?? What else? long...

I have not heard you mention anything about the speed at 2800 RPM but dont assume the tack is correct as they have a 4/6/8 switch becides the other things that could be wrong with it

 

[jello1973]

Re: Wrong gear ratio?? What else? long...

Well... I found out today exactly what I have that's causing my problem. The outdrive has a gear ratio of... get THIS, 1.47:1! It's for a V8!!! My little four banger can't turn it enough since it requires a 1.94:1 ratio. I suppose could sell/trade the one I have, which btw is an alpha1 gen.2.
Seems like the logical choice, but I'm so skeptical at this point... I live in Hudson, FL and if anyone knows someone in this or the Tampa area that is honest and willing to make a deal, please let me know.
For now... I'm dead in the water since the budget is squeezed!
Thanks for any and all your input

 

[Bondo]

Re: Wrong gear ratio?? What else? long...

Ayuh,....

A Brand New SEI upper unit is about $600., which is probably what it'll cost the have Your upper unit Regeared,...
'ell the New Gears would be close to that....Muchless the Labor,+ Seals....

 

[fixb52s]

Re: Wrong gear ratio?? What else? long...

I know a guy there in Hudson who might have a drive. Sent you a PM.​

 

[tmh]

Re: Wrong gear ratio?? What else? long...

People part out boats all the time. Some have drives that are working just fine - find one. Check Craigslist and eBay. Sell yours the same way. When all is said and done you'll break even or be out a few $$$ (IF you can install it yourself, which sounds like maybe you can't). It ain't going to work right with that 1.47 box, that's for sure.

Have you contacted the seller with a "what's up with THIS" question? Who installed the wrong gear box?

Jello, if you're "dead in the water" over this due to budget, I think you need to re-think boat ownership because boats are very expensive to operate and maintain, especially used boats. I'm not ripping on you, I know some folks get into boating thinking the purchase cost of the boat and gas to fuel it are all there is....not! There will be more things that come along that cost $$$ you didn't expect - expect it!

 

[jello1973]

Re: Wrong gear ratio?? What else? long...

tmh... Oh yes, I called the man last night that I purchased the boat from. His response? WHAT?? NO WAY!! Said he never had the outdrive replaced. He said he had the Gimble and the Rams replaced new several mos. ago then the boat sat, which is when he decided to sell it.
Then he told me his only conclusion would be that when it was at the marina THEY must've swapped outdrives... Blah blah! Anyways, I'm over all of that and now I'm in search mode for what I need.
I wouldn't have thought so, but what I need seems to be what everyone else needs and they're a little quicker then myself ;-)
Thanks for all the help everyone, I know it's gonna work out!

 

[jaxnjil]

Re: Wrong gear ratio?? What else? long...

listen to bondo and tmh

 

[jello1973]

Re: Wrong gear ratio?? What else? long...

Update...
Well my problem is solved, I got the correct outdrive put on yesterday. I did some "horse trading" with a local Mercruiser repair shop. I took it out last night for a short test run and MAN what a difference the right parts make! Planes out quickly and runs smooooth... WOT is running around 4400 rpms and I'm happy.
Thanks for all the help and advice!

 

[Bondo]

Re: Wrong gear ratio?? What else? long...

Ayuh,...

I just Love a Happy ending...