mercruiser rotation question

[firedog11ku]

Okay, you guys have been super patient with me, but I have another question.

I have a 1993 caravelle with a mercruiser alpha one Gen II. How do I know what rotation it is. I know by the S# it is a 1.98/1.94 ratio, but not which way it rotates. I need to replace the upper gear housing.

Thanks guys.

 

[Soder99]

Re: mercruiser rotation question

Look at the prop and the direction that it spins will be it's rotation if you're looking at it from the back.

It sounds like you only have one drive in which case it is most likely a clockwise/right handed rotation. But I would double check that by cross referencing your outdrive serial number before putting out money for a part.

 

[Don S]

Re: mercruiser rotation question

Uppers don't care if it's normal or counter rotation. That is taken care of in the lower.

 

[ktbarrentine]

Re: mercruiser rotation question

Upper gear housings all rotate the same way anyway. counter-rotation is done in the lower gearset (for those that have a counter-rotating OD)

(edit: Dang it! DonS beat me again!)

 

[firedog11ku]

Re: mercruiser rotation question

So, as long as I buy an upper case that is an alpha one Gen II with the same gears, I'm golden?

Would I be money ahead to buy a rebuilt upper, or save the $300 and risk a used one from eBay? I'm 'bout as green to boats as there is. I'm more of a car/truck guy. That's why I went with a stern drive, just a car motor with a little different exhaust and cooling system. I'm assuming that the upper case gears are like an axle gear set. As long as they're lubed, they'll last forever.

Thanks again.

 

[achris]

Re: mercruiser rotation question

So, as long as I buy an upper case that is an alpha one Gen II with the same gears, I'm golden?

Would I be money ahead to buy a rebuilt upper, or save the $300 and risk a used one from eBay? I'm 'bout as green to boats as there is. I'm more of a car/truck guy. That's why I went with a stern drive, just a car motor with a little different exhaust and cooling system. I'm assuming that the upper case gears are like an axle gear set. As long as they're lubed, they'll last forever.

Thanks again.

If you have a 1.94:1 reduction, that should mean a 3 litre/140 hp engine. In which case, yes, as long as you keep clean lube there they will last a while...

Chris.....

 

[firedog11ku]

Re: mercruiser rotation question

So what's the difference between the 1.98 to 1 and the 1.94 to 1. I know that one is 1995 and newer, but will either drive be okay?

 

[achris]

Re: mercruiser rotation question

So what's the difference between the 1.98 to 1 and the 1.94 to 1. I know that one is 1995 and newer, but will either drive be okay?

Change in the tooth count in the lower box. Completely interchangeable... The total difference in ratios is all of 2%. You won't even notice it....

Chris......

 

[firedog11ku]

Re: mercruiser rotation question

Thanks chris, again. For some reason your post didn't update on my tablet until 1:07a.m. I wasn't trying to ask a redundant question, but there's an auction that ends in an you or so.