Winter Project 1957 Johnson Javelin

[Crowsbeak]

It’s been a while since I posted but I found my winter project, a 1957 Johnson Javelin, this will be my 1st Big Twin.  The good is it looks complete, came with a set of controls and a junction box.  The controls and junction box will need some work though, additionally it has almost all the chrome (just missing the small Javelin on the bottom of the front).  The bad news is the gear case was cracked bad by the water inlet cover so I got it all for only $100.

I pulled the lower unit apart and the gear set, shift rod, driveshaft all look good. I have pulled the floating bushing, the thrust washer and the pinion gear bearing cages already also.  On an off chance it could be welded I took it to my prop guy and he said the crack goes too far inside the water inlet cover to weld.

In looking at the bible it looks like I could possibly utilize a 1957,58, or 59 Johnson RD 19 or 20 case or Evinrude Lark gearcase of the same timeframe but want to make sure I am limited to those years and models?  I have posted a want ad in the classifieds as well.  I have posted some photos below.  Any thoughts appreciated.

Thanks,

Crowsbeak

1954 Evinrude 7.5 HP
1954 Evinrude 15 HP
1954 Gale 12 HP
1955 Johnson 10 HP
1956 Johnson 10 HP
1956 Gale 12 HP
1956 Evinrude 5.5 HP
1957 Johnson Golden Javelin 35
1958 Johnson 7.5
1960 Evinrude 18 HP
1973 Johnson 6 HP

[labrador-guy]

Nice motor there Crowsbeak!   I built an Evinrude last winter.  It also had a cracked LU.  I found another and she’s ready to go.  I sold it a couple weeks ago.   I have another and I sure did not need two!

dale

 

[outbdnut2]

The upper and lower gearcase halves are final machined together at the factory, giving a matched set, so, if you can, replace both halves with a set from another motor, instead of just replacing the cracked half.   Usually it works to replace just one half, but you may have trouble getting it sealed good.

Dave

[Crowsbeak]

labrador-guy wrote:

Nice motor there Crowsbeak!

Thanks Dale!  Looking forward to trying to get it to look 1/2 as good as yours.

Thanks for the heads up Dave.  I’m hoping maybe one of our members may have a matched set from a donor motor they can part with in response to my classified ad.

Another question, the Red Book mentions an upgraded water pump housing for the big twins with a stainless baffle added but doesn’t list a part number and marine engine doesn’t show a superseded version but does mention two impellor sizes.  I have the original water pump version so wonder if anyone has had trouble running that old style pump?

1954 Evinrude 7.5 HP
1954 Evinrude 15 HP
1954 Gale 12 HP
1955 Johnson 10 HP
1956 Johnson 10 HP
1956 Gale 12 HP
1956 Evinrude 5.5 HP
1957 Johnson Golden Javelin 35
1958 Johnson 7.5
1960 Evinrude 18 HP
1973 Johnson 6 HP

[fleetwin]

outbdnut2 wrote:

The upper and lower gearcase halves are final machined together at the factory, giving a matched set, so, if you can, replace both halves with a set from another motor, instead of just replacing the cracked half.   Usually it works to replace just one half, but you may have trouble getting it sealed good.

Dave

Replacing just one half of the gear housing is a big risk, especially on a higher HP engine like this one…

[outbdnut2]

You wrote:  Another question, the Red Book mentions an upgraded water pump housing for the big twins with a stainless baffle added but doesn’t list a part number and marine engine doesn’t show a superseded version but does mention two impellor sizes.  I have the original water pump version so wonder if anyone has had trouble running that old style pump?

My Sierra catalog shows a new impeller beginning in 1958.  Your golden javelin is a 1957.

1951-1957 is Sierra 18-3006, OMC 378891, superceded by 775521

1958 -1970 is 18-3083 OMC 377230, superceded by 777213

Dave

[Crowsbeak]

fleetwin wrote:

Replacing just one half of the gear housing is a big risk, especially on a higher HP engine like this one…

Great news!!  I was able to source a new lower unit locally today.  On to the reseal!

outbdnut2 wrote:

My Sierra catalog shows a new impeller beginning in 1958.  Your golden javelin is a 1957. 1951-1957 is Sierra 18-3006, OMC 378891, superceded by 775521 1958 -1970 is 18-3083 OMC 377230, superceded by 777213

Thanks for the part numbers Dave!

I guess I am still wondering if anyone has experienced the loss of seal mentioned in the service bulletin that resulted in them revising the pump housing design.  If it happens, I suspect the motor may overheat?  When I look on marine engine you can still buy the old style pump housing but there is no mention of the new style nor is it listed as a superseded part number so I wonder if the new pump design didn’t actually work better?

1954 Evinrude 7.5 HP
1954 Evinrude 15 HP
1954 Gale 12 HP
1955 Johnson 10 HP
1956 Johnson 10 HP
1956 Gale 12 HP
1956 Evinrude 5.5 HP
1957 Johnson Golden Javelin 35
1958 Johnson 7.5
1960 Evinrude 18 HP
1973 Johnson 6 HP

[outbdnut2]

I have had no problems with the seal you mentioned in my 1956 and 1957 30 and 35 HPs….including a Golden Javelin like yours, but obviously, some must have had problems for the design change to be made.

Dave

[Crowsbeak]

Thanks again Dave.  I’ll run the water pump housing I have.

My next issue is the lower off a 1957 35 I have gotten from the boneyard of my local shop is to the best of my research likely off a 1956 30hp which means it has the same gear set minus the pinion which is the shorter version with a tapered roller bearing as opposed to the revised with the regular roller bearing with the thrust washer and needle bearings.  They just gave it to me as they are relocating and wanted it gone so nothing to get upset about.

This motor certainly won’t be used for anything like water sports, but do I need to try to source an actual 35 hp lower?  Everything in this new lower unit looks great and I would have run it initially till I knew the motor was a runner without knowing but I decided to pressure test it 1st and found it leaked so I disassembled and discovered the year discrepancy.  It looks great and no cracks but will a 35 destroy this without the extra support of the taller pinion?

1954 Evinrude 7.5 HP
1954 Evinrude 15 HP
1954 Gale 12 HP
1955 Johnson 10 HP
1956 Johnson 10 HP
1956 Gale 12 HP
1956 Evinrude 5.5 HP
1957 Johnson Golden Javelin 35
1958 Johnson 7.5
1960 Evinrude 18 HP
1973 Johnson 6 HP

[outbdnut2]

The lower was beefed up in 1957 to handle the increased HP.  The  1974 Johnson parts swap manual does NOT list the 30 HP  gearcase assembly as a swap for  1957  and newer models .

 

It will probably bolt up and work though!

Dave

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