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1979 70hp evinrude or Johnson lower gear case removal

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primodude

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Here is a tough one.... I am about the 3rd owner of this motor (and boat) and I am attempting to install a new impeller assembly. Whoa....whoever owned this motor earlier, used some kind of gasket maker to seal the lower casting to the central castings...
I have removed the 5 bolts necessary to lower the casting, but no wiggle insight. I am desperate for a solution in some kind of solvent that will unseal the lower unit.... IF THERE IS A GASKET MATERIAL USED.
I don't see any external view of anything that resembles material.. so there very well not be anything used.
But I suspect.
If not.. then how do you get this puppy loose so I can finish my impeller installation. ??? Please help.
PrimoDude.
 
racerone said:
You should have 7 bolts, a shift pin and a trim tab on your workbench !
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Thank you for the reply.... There are only 4 bolts on the external casting and 1 bolt beneath the trim tab, and I do have the shift pin removed as well. Any ideas on a possible solution to use to soften any possible adhesive materials??
PS the joining edges are very thin between the two castings... No evidence of adhesives, just suspect. How do you suggest prying this assembly apart???
 
Do not force anything be sure and tie a rope around it to catch it when it breaks loose. You do not want it landing on your foot or on the concrete. Use a torch and heat around the seam just dont burn the paint you can get it fairly hot, then with a chunk of wood and a hammer shock it side to side till it breaks loose. Be patient.
 
kimcrwbr1 said:
If you focus the brunt of the force on the bullet part of the gearbox that is the strongest part.
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Great idea.. off to get a torch..... I don't want to break or cause cracks....
Will post results.. I am thinking also of using some Carbon Technicloride (sp) solvent around the edges..but I see NO adhesives... but if there are.. then I am in deeeeep troubles.
PS... I am leaving the 4 external side bolts loosely attached to prevent toe damage.. :)
 
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You should have 7 bolts and the trim tab on your workbench !!-----Yes that is the count on the fasteners that hold this unit in place.---Done this job a 100 times meself.-----The other possibility is the driveshaft and cranshaft splines jammed with rust !
 
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primodude said:
Thank you for the reply.... There are only 4 bolts on the external casting and 1 bolt beneath the trim tab, and I do have the shift pin removed as well. Any ideas on a possible solution to use to soften any possible adhesive materials?
Click to expand...

There is not a sealant in the marine world that will glue those two sections together as you indicate. As "racer" states, there are seven (7) bolts retaining that lower unit...... 4 which are obvious, 1 holding the trim tab, 1 under the trim tab, and 1 directly in front of the trim tab... seven (7).

With those bolts removed, assuming the shift rod is free, the lower unit should drop away. If it does not, it is usually a case that someone did not install the top driveshaft O Ring and grease the upper splines.
 
joereeves said:
There is not a sealant in the marine world that will glue those two sections together as you indicate. As "racer" states, there are seven (7) bolts retaining that lower unit...... 4 which are obvious, 1 holding the trim tab, 1 under the trim tab, and 1 directly in front of the trim tab... seven (7).

With those bolts removed, assuming the shift rod is free, the lower unit should drop away. If it does not, it is usually a case that someone did not install the top driveshaft O Ring and grease the upper splines.
Click to expand...

Heading out to double and triple check Man... I sure hope your correct. And I have t assume you are. This is my first dance... aside from 6hp.
:)
Oh... I was not counting the trim tab bolts... the trim tab is off entirely, the bolt under the trim tab plate is removed, the shift bolt is removed, the gears are in reverse, and with those two extra trim tab bolts, I should have 7, but counting again.
 
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I have been blessed.
My many thanks to all who have responded..... I counted bolts again, and only had six showing.
Rechecking the trim plate access hole and lo and behold... I missed a bolt.. the lower casting is now LOOOOOOSE.
My dance is improving....... onward and upword.... and again... Thank you thank you and thanks again.
Primodude

 
primodude said:
I lie a little bit too.....forgive me... now tussling with the old impeller, stuck on the main drive shaft. Really stuck and no bolts... :)
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Oh...your question...yes....the bolt that is deeeeep inside under the trim tab... The one you have to use a extension on the socket.
 
primodude said:
I lie a little bit too.....forgive me... now tussling with the old impeller, stuck on the main drive shaft. Really stuck and no bolts... :)
Click to expand...

If that's a woodruff key.... split the impeller with a chisel.

If it's one of those plastic things..... belt the impeller back and forth with a hammer & punch.

And stop that lying... ya'all can go t'hell fer that ya'know!
 
joereeves said:
If that's a woodruff key.... split the impeller with a chisel.

If it's one of those plastic things..... belt the impeller back and forth with a hammer & punch.

And stop that lying... ya'all can go t'hell fer that ya'know!
Click to expand...

Well, I succeeded in banging it loose.. Used a flat head screwdriver underneath the brass round of the flippers, and then another screwdriver shaft under for a sort of bench to leverage the bigger flat head under the brass gizzy. Then tapped and rotated positions... gradually it gave way and slide off... I tell truth now.. :):cool:
 
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