1950 Merc KG7 Gear Case Question

[45calmuzzleloader]

I'm fixing up Dad's Mercury 1950 KG7. It has the regular fishing lower unit. I am in the process of replacing impeller, cleaning and repacking all the gear case bearings, and replacing the seals. I was wondering if anyone could tell me how to set the clearance on the gears. My drive shaft has a lot of vertical endplay when the lower is seperated from the exhaust housing. Is this normal? Thanks.

 

[Chinewalker]

Re: 1950 Merc KG7 Gear Case Question

Is the pilot cap on the gearcase in place when you're checking the vertical endplay? The pilot cap is what holds the upper seal in place. It also gets sandwiched between the gearcase housing and the exhaust housing, in effect holding the upper driveshaft bearing in place. Plus - how much is "a lot"? There will be some - maybe as much as a few hundredths of an inch. If you're getting 1/8 inch, then something is either very worn, or not assembled correctly.

I am assuming you've had the gearcase completely apart - are all the shims back in place in the same spots they came from? If you just cleaned and grease everything and have not changed anything else in the gearcase, then re-shimming it should not be necessary.

 

[45calmuzzleloader]

Re: 1950 Merc KG7 Gear Case Question

Thank you for the reply Chinewalker. Yes, the pilot cap is off when I was checking the gears. I removed the water pump and prop shaft. It looks like the lower may have been run without the pilot cap installed because the upper drive shaft bearing was flush with the top of the gear case when I got it (bought a used gear case to replace the original Dad tried to use for a underwater power saw). The gears have a funny wear pattern to them, may be able to run them. I have a main gear in very good condition, from another lower, I hate to ruin it with a not so good pinion. Maybe I can locate a better pinion gear some day.

 

[Chinewalker]

Re: 1950 Merc KG7 Gear Case Question

Only reason I can see why the upper cap may have been removed is that the upper bearing may have been replaced at some point. I know Mercury has some proprietary bearings that are odd sizes and the off the shelf bearings are a bit thicker, thus making it difficult to get the pilot cap back in place. Gotta have it, though. Do you have the cap? I have a complete gearcase here if you need one...

Not sure if you've ever run a KG7, particularly on a light tinny, but they are literally a handful! Lots of fun, but play safe. Make sure there's a little tension on the co-pilot screw on the clamp brackets, as they can get away from you if you're not careful. With the throttle on the mag lever, it makes 2-handed operation a necessity. Nothing like skimming a 12-footer at 30mph! I went through mine several years ago and it is one of the sweetest running motors I own!

 

[45calmuzzleloader]

Re: 1950 Merc KG7 Gear Case Question

I have the pilot cap with upper seal from Dad's original gear case. The gear case I purchased did not come with one, and from the rough wear pattern on the gears it looks like it was run without one for a short time. I am very interested in your gear case. How do the gears look? How much are you asking for it? How can I contact you? I have 1 very good main gear, 2 good prop shafts, 2 good drive shafts, 1 super good housing, 1 decent housing, 2 water pumps, and bearings. Can't have too many spare parts! I have never seen a KG7 run, this ones lower unit has been a basket case since 1954-55. But it's got 130 psi on the bottom and 125 psi on the top. One compression ring is sticking a little facing the exhaust port on the top cylinder, but its free on the intake side of the piston so I think it will loosen up once I get her running. I have cleaned the carb and bought new coils and condensers for the Scintilla magneto. I remember Dad said he put new points in it before the lower got trashed. The gas tank has 2 small dents or so and the bottom cowling looks very good, just need to locate or fabricate a couple of those 1/4 turn fasteners.

 

[Chinewalker]

Re: 1950 Merc KG7 Gear Case Question

Send me a PM about the gearcase...

As for the Dzus fasteners, there's a guy at the AOMCI.org site who has repopped them. He advertises them periodically on their Webvertiser, name is Tom Scileppi.

- Scott

 

[bktheking]

Re: 1950 Merc KG7 Gear Case Question

Yup, he sells them for $6 each. Have fun with that scintilla mag, they are a treat to get working perfectly.

 

[45calmuzzleloader]

Re: 1950 Merc KG7 Gear Case Question

Chinewalker, tried to send 2 different PM's but got error messages stating your mailbox is full and can't take anymore messages.