lower unit wont budge on my evinrude 1978 75hp

[derrhalt]

struggling big time removing lower unit. i removed all the bolts and (2 twisted off and broke), trim tab bolt, other big bolt underneath, and shift linkage........nothing moves at all. seems like the lower unit is almost fused to the upper unit. banged on it with rubber mallet but nothing. any suggestions would be greatly appreciated!

 

[racerone]

Re: lower unit wont budge on my evinrude 1978 75hp

On motors that are neglected / not maintained it is quite common for the drveshaft to be stuck in the crankshaft.------Moisture / oxygen get in there and the crank spline rusts.---The oxygen that is added to form iron oxide ( rust ) jams it all up.

 

[derrhalt]

Re: lower unit wont budge on my evinrude 1978 75hp

what are my options?

 

[bonz_d]

Re: lower unit wont budge on my evinrude 1978 75hp

As racerone stated, it isn't uncommon. This will also happen if the oring on the driveshaft has been left off. I know this from 1st hand experience with a used 70hp Evinrude that come on the Alumacraft I bought.

The splines on the driveshaft and inside the crank were so worn that the shaft actually started to twist inside each other. As this engine was already toast from the previous owner trying to remove it I had to cut the exhaust tube and driveshaft to remove it.

As I found after I had it cut off, had I know of this condition I found that if the prop shaft could have been locked in place and the crank turned in a counter rotation I probably could have turned everything so that the splines lined back up and it would have dropped.

There is no easy way to remove a stuck shaft, ALL involves time and the chance that something is going to get damaged.

One of the 1st things you should try is to remove the engine and stand it upside down. Then turn the transome clamp to one side and you should be able to see the shaft where it enters the powerhead. With that try soaking it with some good penetrating oil. Then try again with that deadblow hammer.

 

[derrhalt]

Re: lower unit wont budge on my evinrude 1978 75hp

I found one bolt that i missed under the trim tab, but unfortunately twisted off. My big problem is the 4 bolts that attach the gear case 2 of the 4 bolts that broke off when trying to remove them. have no clue how i will be able to get them out. any suggestions?

 

[nwcove]

Re: lower unit wont budge on my evinrude 1978 75hp

did they break off flush, or is there enough on any of them to grab with a good set of vicegrips? if there is enough to grab, you can get lucky with some heat and penetrating oil, and patience. if not, you will need to carefully drill them out and maybe retap the threads one size larger. if you dont have the tools or confidence to do that, call a machine shop and explain your situation. jmo

 

[derrhalt]

Re: lower unit wont budge on my evinrude 1978 75hp

ok.....great news. I got it off. 3 broken bolts that need to get out but pretty happy. the lower unit was pretty bad. corrosion and rust on drive shaft. got water pump off. my question is, is the drive shaft ok if it is rusty? it spins and i think i can get most of rust off. What is the best way to clean the whole lower unit? powerwash or steam clean to get all the gunk and corrosion off it? going to replace water pump and impeller and new lower unit oil. any other suggestions would be appreciated!!

 

[Bosunsmate]

Re: lower unit wont budge on my evinrude 1978 75hp

What colour was the gear oil?
driveshaft should clean up fine