54Evinrude Big Twin crankcase

[dougs-outboards]

Is it possible to carefully use a little propane heat on the seams to loosen the sealer?

[chas56x]

In your second picture, showing the top of the crankshaft, try wedging a flat blade screwdriver between the bolt hole and the flat arm sticking out. Then pry gently. That should break the crankcases apart.

[fleetwin]

Do you have a firm rubber or big plastic mallet? If so, rapping forward on the crank usually does the trick pretty quickly. Figure out some way of securing/clamping the powerhead so you aren’t chasing the powerhead all over the bench. If you don’t have a suitable soft mallet, have an "assistant" hold a block of wood against the crank while you rap on it with a suitable hammer.

[olcah]

Got it open. It took several hits with a claw hammer and pine block and then it came open. Thank you all so much for the advice.
Charlie

[mas]

quote fleetwin:

OK, here are Olcahs pictures, looks like he has got all the bolts out to me, but best to have others confirm…
Pressure tank check valve is definitely NFG though…

What are you seeing????

Mart

[fleetwin]

Charlie had a thread earlier this fall concerning a leaky top seal on this engine, he decided to split the crankcase halves to see if there is some sort of leaking/sealing problem with the crankcase halves that might explain the leaks he was seeing onto the mag plate.

[olcah]

I will get some pictures and info together and post them soon.
Thanks,
Charlie

[fleetwin]

Hmmm, just a thought after looking at pictures #3 and #4 again…
One of the pressure valves for the tank is stuck open slightly. Is there anyway the pressure leak back from the tank entering that passage might be directed up the vacuum port for upper bearing drain? I kinda doubt it, but hard to tell until that gasket is removed…..

[olcah]

http://s77.photobucket.com/user/cheryls … ml?filters[user]=143951230&filters[recent]=1&sort=1&o=1
http://s77.photobucket.com/user/cheryls … ml?filters[user]=143951230&filters[recent]=1&sort=1&o=0

Please look at the thread "54 Johnson RD15A Top Seal (still() Leaks" from September which has a great explanation of how the top seal is supposed to drain by Frank Robb. Above is what I saw when opened. No smoking gun. I noticed that the top bearing has an o-ring which surprises because the final setup is not supposed to have an o-ring. The seal is supposed to drain thru a very small hole in the old o-ring groove. See photo below. The toothpick is stuck in the hole as I could not get a good photo. Shooting a little WD40 in the hole shows it drains to the reed plate and then thru the plate into the intake. (Frank’s explanation in the old thread is best.)

http://i77.photobucket.com/albums/j66/c … dudclx.jpg
http://i77.photobucket.com/albums/j66/c … yievob.jpg
The Johnson and Evinrude 25HP for 1954 are identical but the Evinrude parts book shows an o-ring around the top bearing while the Johnson book does not. My motor has that ring. Here is the top seal area.

http://i77.photobucket.com/albums/j66/c … gqxtb0.jpg

http://i77.photobucket.com/albums/j66/c … kdvbzd.jpg
http://i77.photobucket.com/albums/j66/c … 8f9ven.jpg

Will go with what I think is the latest configuration and put the motor back with no top o-ring at the bearing. The top seal already has a new carbon and new square ring that I put in last winter. Will check lower seal and replace the o-ring in the carbon also.

Thanks to everyone and for sure open to suggestions.
Charlie

[olcah]

Can’t open ist 2 photos. Try again.
http://i77.photobucket.com/albums/j66/c … 99wqcz.jpg
http://i77.photobucket.com/albums/j66/c … k1msit.jpg

[Author]

Posts