1950's small jonhson ID

[robtherep]

hello<br /><br />does anyone know anything about these old motors?<br />i am trying to make 1 good one. one is MOD. TN 27<br />other is MOD. TD 20. <br />-can parts be interchanged?<br />-horsepower<br />-year<br />-anything about them would be great.<br /><br />thanks alot

 

[Paul Moir]

Re: 1950's small jonhson ID

Yes, parts will interchange. They're both 5hp, but I belive the main difference is the shifting lower unit on the TN-27.<br />I've never owned one but those who have seem to rave about them a lot.<br /><br />The TD-20 was built between '46-'49 and the TN-27 was built '50 and '51. If you can furnish S/Ns I can pin down the exact year but it's really academic. Nothing got changed during their runs.<br /><br />Both run 24:1 according to the ~1964 OMC bulettin, but originally ran 16:1. Use TC-W3 oil though as it's vastly superior to SAE 30w. <br /><br />I'm sure folks who know them better will be along shortly.

 

[Dunaruna]

Re: 1950's small jonhson ID

TD20 - 1946 to 49, 5hp.<br /><br />TN27 - 1950 to 51, 5hp.<br /><br />JB probably knows details about these, hopefully he will be along shortly.

 

[JB]

Re: 1950's small jonhson ID

The TD-20 uses Champion J8C plugs gapped at .030"<br />The TN-27 uses Champion J6C, gapped the same.<br /><br />Both magnetos want the points set at .020"<br /><br />Good luck, you have a couple of jewels there.

 

[robtherep]

Re: 1950's small jonhson ID

Priceless info thank you. I picked the twins up this morning and can’t break away from them, hoping to get the TN 27 SER. 113077 running soon. The TD 20 SER. 690 39 is almost all there. Might keep for parts or find parts and get it going as well. <br />I don’t know how difficult it is to get parts. I guess on e-bay or something.<br />This is my first year with boat motors and I can’t break away from them. I ‘m sure I would never use them yet I don’t think I could sell them. I like the way they pivot on their horses giving easy access to every part. They look like 2 little Martians.

 

[Paul Moir]

Re: 1950's small jonhson ID

The S/Ns look like they're missing a number or two, but I'm pretty sure the TN is a '51 and the TD is a '48.<br /><br />Parts are somewhat hard to find for these, but improvising is possible. The "impellers" are available from Marx: www.grove.net/~noff/marx.html. Carb kits don't exist, but you can cut the gaskets yourself and there's a Merc float that can be modified to fit the originals. Points are available for something like $20 each, but often they can be cleaned. Ignition coils are not available, but they're not often a problem (unlike the '52- coils)<br /><br />If you need parts, ask here. Often someone will have a lead.

 

[Scaaty]

Re: 1950's small jonhson ID

Originally posted by roboat:<br /> They look like 2 little Martians.

 

[robtherep]

Re: 1950's small jonhson ID

Hello<br /><br />I got little green Martian TN27 started today. He ran for 30 seconds or so a couple times sounded great. My wife and neighbor came to see and hear. It was a festive occasion.<br />A good performance for someone so old and only sparking on 1 cylinder and gas pouring out of the hole on top of the carburetor, the part where the float is. I think the float is the problemb but don't really know how they should be working.

 

[AEROCOOK]

Re: 1950's small jonhson ID

My buddy just gave me a TN27 on the weekend, no time to work on it yet though.<br />The motor is complete and original including the decals on the side and front. I may look to you for some tips if you dont mind.<br />BTW he also gave me a 51/52 10hp Johnson and a 1957 5.5 hp Johnson... Looks like I found a new hobby!