Merc 650 prop shaft seals

[RRafkin72]

I have a 1970 merc 650 4cyl. I'm trying to replace the prop shaft bearing carrier oil and water seals. Is there any way to do it without removing the bearing carrier assy? I attached 2 pics of the diagram for the lower. #74 is the seals im trying to replace.
Cheers

 

[jimmbo]

There are tools that can extract Seals in place. They kind of look like a piece of Threaded Pipe, fit over the propshaft and then turned, The Threads bite into the seal and then it can be pulled out. Don't go trying to use a piece of Iron Pipe, as it is too rough inside and will damage the Propshaft sealing surface
Some people will drill a couple of small hole in the Seal, then screw in a couple of screws to grab on. Again there are Risks at damaging the Propshaft.
It is safer, just to remove the Carrier

 

[RRafkin72]

There are tools that can extract Seals in place. They kind of look like a piece of Threaded Pipe, fit over the propshaft and then turned, The Threads bite into the seal and then it can be pulled out. Don't go trying to use a piece of Iron Pipe, as it is too rough inside and will damage the Propshaft sealing surface
Some people will drill a couple of small hole in the Seal, then screw in a couple of screws to grab on. Again there are Risks at damaging the Propshaft.
It is safer, just to remove the Carrier

Right on, any tips for removing the Carrier? I don't have a manual But I do have a shop full of tools. I've done that trick with the screws and drilling into the seal but only on larger lip Seals... seems risky on such a small one...guess I just have to pull the Carrier and do it right

 

[racerone]

On a fresh water motor you bend one tab on the lock washer then remove the big nut.----Slide hammer and a hook to pull carrier out.

 

[RRafkin72]

Update
Bearing carrier and prop shaft are out. Bearing carrier is cracked and NOS on is on its way. Prop shaft cleaned up nice with some emery cloth and scotch Brite, will go back into service. Gears teeth look really good minus 1 very small chip on the edge of 1 tooth on the reverse gear. I think I will carefully hand file it down a smidgen and run it . Spring clutch has some wear on the dogs, to me looks ok considering it's 50+ years old. Let me know what you guys think. And for the record I did not break the bearing carrier on removal it came out missing a huge chunk that is likely in the bottom of some body of water somewhere

 

[jimmbo]

Clutch Dog needs to be replaced. How does the Forward Gear look? One Chipped tooth usually becomes several shipped teeth in short order.

 

[Faztbullet]

Yes dog needs replaced

 

[RRafkin72]

Ok, thanks guys...
I've got a new sliding clutch on the way. Also looks like I goofed up and got the wrong bearing carrier, so I've found and ordered another that is a match. I think I've had some trouble with getting correct parts because I've been using my engine serial number and my lower came off a different unit possibly a 6cyl. ? I'm not sure, but the serial numbers are pretty close so I thought I'd be ok...guess not

 

[Chris1956]

See if you have a part number on the gearcase so you can ID it.

 

[RRafkin72]

See if you have a part number on the gearcase so you can ID it.

I don't see any numbers on the outside, but it has definitely been re painted so who knows...I have a serial# the seller gave me, and he had it listed as a 1966-78 4cyl. Inline 65/80/85hp. The serial is 2804236, which i looked up and believe to be 1970?

 

[jimmbo]

1971 was the last year for the 4 cylinder 65hp. It shares the Gearcase used by the 4 Cylinder 80 and 85hp, and used the same Gear Ratio of 2.3:1. A Case for the Inline 6s would fit, but they usually had a 2:1 ratio, though some were 1.78:1(1972 115)

 

[RRafkin72]

Thank you everyone for all the help.
I got the gearcase disassembled minus the reverse lock. I decided to go ahead and look for all new gears and do it right...
...so I went ahead and ordered NOS gears, bearing carrier, and seals from a 650 diagram I found online, they showed up and are definitely different than what I pulled out...

I finally found a number on the fwd gear I have here, and when I put it in a search I'm getting 115hp, which would mean this lower came off a 6cyl right? In which case it won't be the correct gear ratio to use with a 4cyl 65hp.. is that correct?

I'm thinking about just looking for another complete engine/lower and selling what I have but I'm not sure if I should. I am able to find the actual correct gears for my lower but haven't pulled the trigger yet. I found a decent complete 1973 running 115hp for sale, with a short shaft. Right now I have a long shaft setup (not really sure if I need long or short)...if needed would it possible to swap my driveshaft, housing, and lower to make it a longshaft?

 

[jimmbo]

What is the Height of your Transom, 20" or 15"?
The 4 cylinder 65hp used a 2.3:1 gear ratio, most of the inline 6s used 2:1, but some, the 1972 115, showed a 1.78:1 in the Brochure.
Count the teeth on the gears and you certainly will be able to figure the Gear Ratio.

Here is another Curve, when it comes to these Gearcases, When any gears or Bearings are changed, they need to have the Clearances checked and adjusted.

Another complete case from a later 4 cylinder 75, 80, 85hp, should bolt right up. One from an Inline will, as you may have found out. While a change in Pitch can get the WOT Rpms back to where they should if the wrong Ratio is used, the proper Ratio is still a better choice.

Long or short shaft.... What is the Vertical Measurement of the Transom? 15" is short shaft, 20" is long shaft. 99.99% of the time, the engine and the Transom have to match, or be quite Close. On these engines, to change from one to the other, involves different Exhaust Housing, Exhaust Tubes, Water Tubes, Shift Shaft, Driveshaft, and a lot of Labour/Time to do the swapping

 

[RRafkin72]

The transom measure 20" so looks like short shaft wouldn't put the cavitation plate below the hull so thats out of the question.

I likely won't go this route but I'm curious if anyone knows, would my driveshaft housing from my 650 bolt up to an 1150? and would my exhaust and water tube and shift shaft and 20" driveshaft from my lower then work? Obviously lots of labor and I'm trying to avoid that but I'm wondering.

How much later in years can I look for a lower that works with my 1969 650?

 

[RRafkin72]

It looks like the lower I have is indeed 2:1 ratio. 28 teeth on the forward and reverse gear and 14 teeth on the pinion.

 

[jimmbo]

Easiest and likely least costly, is to find a Lower Unit, from a 4 cylinder 75, 80, 85hp. The 79 and later have slightly more Hydrodynamic shape.

 

[RRafkin72]

Thank you jimbo.The search is over! Cost me a few shillings but hopefully I can sell my complete 50hp and 6cyl lower to make up for it...I can't believe I found a new old stock complete lower unit and from what seems like a reliable seller! With a 6 month warranty! Thank you to everyone who's helped, I really didn't look before I leaped into this, but I've learned a lot and now I'm closer than ever. Back to deciding where to start with prop size

 

[jimmbo]

Before you install it, replace the Water Pump Impeller. If it has been sitting 45+ yrs, I wouldn't trust it.