Outdrive for my Merc 3.7 non tested

[alexr254]

This outdrive... I dont know what type/model it is, and i have never had it tested or used... We took it off of a boat i recently got.

From the picture you can see a pretty good sized hole at the back, it does not go all the way through, but i dont know how this could have happened or if its reason for any drastic action, like replacing the drive for another one.

I was thinking of rebuilding it, painting it and filling the dent.. if its worth it. If not i will get a new one from iboats for roughly $1.5k, once i know the exact model.

 

[Don S]

Re: Outdrive for my Merc 3.7 non tested

You might be able to see a hole, but I can't. Does it have the correct gear ratio for your engine? If it was for a V8, for get it. Wrong ratio. With the price of parts to fix it, and a hole in the housing, and obviously a salt water drive. It sounds more like scrap metal than a usable drive.

 

[alexr254]

Re: Outdrive for my Merc 3.7 non tested

Thanks Don,
I circled the hole here.

The outdrive is from a mercruiser 470 3.7 ltr, 4 cyl.

 

[alexr254]

Re: Outdrive for my Merc 3.7 non tested

So this is an Alpha 1 Gen 1 ?

 

[Don S]

Re: Outdrive for my Merc 3.7 non tested

So this is an Alpha 1 Gen 1 ?

Hard to say, could be an R, MR, or Alpha I.
Do you have the serial number off the drive?

 

[alexr254]

Re: Outdrive for my Merc 3.7 non tested

I will take a look again when i get home later. From my initial searches for numbers, i couldnt see any. Will update this post a bit later with any numbers i can locate.

thanks

 

[Eric 3.7LX Alpha 1]

Re: Outdrive for my Merc 3.7 non tested

That hole is in the area of the shift shaft of the lower. There is a hollow cavity around the shaft where that small hole below drains water from.

I'm not sure if that area is in oil or the hollow part,

If it is not thru, you might be ok, I'd pressure test the drive and see how it does.

 

[alexr254]

Re: Outdrive for my Merc 3.7 non tested

I searched and searched.. with no luck.

I found no numbers at all..

This is the original outdrive that is for a Merc 470 3.7ltr engine.

Is there any other way for me to figure out the gear ratio and model of this drive? I would like to be sure if i replace it, i replace it with something correct.

 

[ziggy]

Re: Outdrive for my Merc 3.7 non tested

a 470 should be a 1.84:1 gear ratio. unless there's a H stamped on the universal joint splined yoke, then it'd be a 1.36:1.

ya can physically check for gear ratio too.
this is a c & p from someone here on iboats from a long time ago. i saved it to pass along to others. sorry as to not crediting the author..

Do all these steps in order.
1. Shut off the battery switch
2. Pull the spark plugs out of the engine.
3. Put the shifter in forward.
4. Turn the engine till the prop starts turning, continue turning till the timing mark is at TDC.
5. Put a mark on the prop hub and the drive housing that align with each other.
6. Turn the engine by hand while someone watches the marks on the prop, and count the revolutions the crankshaft makes to turn the prop 1 complete revolution.
7. If it took 1.5 revolutions of the crankshaft, then you have a drive ratio of 1.5:1 which is what is needed for a small block V8. (a 260).

ya can count gear teeth too in the upper. between the drive and driven gear.

on you s/n. your choice as to if ya wanna do this or not. but the s/n 'may' be stamped into the drive, under the mercruiser sticker.

like that, this is a '72 mc-1 drive. i don't know if this location applys to the 470 or not. so again, your choice as to destroying the sticker. ya have to look close to see the number too. mine was etched so lightly as that it couldn't be seen at all with paint over it. hence me scapeing off the paint to see the number. look close to see the number.

that's where the s/n is supposed to be on my vintage drive.
these are two different drives. the good one is a a '75..

 

[alexr254]

Re: Outdrive for my Merc 3.7 non tested

The sticker is basically gone anyway. I will try to rub it out at that spot, if its stamped in, it should be there.