1977 Merc 4.5hp longshaft

[sutor623]

Hey fellas, got a hold of a greattttt running 4.5hp for $50 yesterday. It needs a waterpump, but I can't get the durn lower unit off. All that I could see was a 1/2" nut in the front right above the prop, and another 1/2" nut in the back of the lower unit. Loosened those suckers up and the L/U will not budge. I can get the casings to split ever so slightly. I just have one question. Am I missing something or am I seized up at the powerhead??

 

[sutor623]

Re: 1977 Merc 4.5hp longshaft

Nobody can confirm if these are the only 2 nuts? I have the motor hanging upside down from my back deck from the L/U with some PB blaster running down the driveshaft.

 

[Mi duckdown]

Re: 1977 Merc 4.5hp longshaft

Those are only fastners that I know of. You could try making some oak wedges and tap them between the casing. Peronally I like useing Marvel Mystry oil it flows much better down the shaft.

 

[MercMan82]

Re: 1977 Merc 4.5hp longshaft

I think you got the same motor as me. There are only the two bolts that you took off. If the lower unit hasnt been opened in awhile, it's just stuck. You're doing the right thing. Tap on each side with a rubber mallet alternating and the wedges idea will help too.

 

[sutor623]

Re: 1977 Merc 4.5hp longshaft

Okay thanks for the reply fellas. I have had units get stuck on me, just wanted to make sure that I wasn't going to break anything off by using force. I thought that I had gotten all the nuts loose. Is this marvel mystery that you speak of the air tool oil?

I have separated the casing about 1/4" all around. I actually drilled a tiny hole in the midsection all the way up by the powerhead so that I could get my red nozzle tight up to the powerhead/driveshaft. From what I have heard, this motor has the most RIDICULOUSLY placed powerhead, so I am trying to avoid pulling it at all costs. We'll see how that goes.......

 

[MercMan82]

Re: 1977 Merc 4.5hp longshaft

Oh yeah also, some tips to keep in mind for stuck things. If a bolt is stuck use heat and penetrant oil and let the oil work. The key is to get play in the piece you want to remove, then work the play with lots of patience. In this case you have some movement, so knock it back tight and then try and separate it again. Do this several times and see if you get more play as you go. With a stuck bolt, try to tighten it first then loosen. If you get any play then work the play back and forth heating the bolt again as it cools.

 

[jbjennings]

Re: 1977 Merc 4.5hp longshaft

I've pulled that little single cylinder powerhead on one of those several times. It's not bad at all. You're right, the lower unit should come off after those two nuts are removed. Something is stuck. Pulling the powerhead wouldn't be a bad idea.
Just buy the base gaskets and have them ready.
Good luck,
JBJ

 

[sutor623]

Re: 1977 Merc 4.5hp longshaft

I've pulled that little single cylinder powerhead on one of those several times. It's not bad at all. You're right, the lower unit should come off after those two nuts are removed. Something is stuck. Pulling the powerhead wouldn't be a bad idea.
Just buy the base gaskets and have them ready.
Good luck,
JBJ

Well, I think that I am going to try strapping up to two come alongs and going that route. If I feel like something is not right, I will pull the head. I have 3 motors out of commission with the powerheads pulled right now, so I do not want to have yet another project setting around. We'll see though, I'll let you guys know how it goes tonight and tomorrow....

 

[sutor623]

Re: 1977 Merc 4.5hp longshaft

Okay fellas success!! I got it apart with a come along tied to a tree. I tried to slip the L/U back on just for kicks, and it seems like it is goin to be a BEAR to get this thing back on. Obviously you can wiggle the shifter and flywheel to mate up with the splines, but I was wondering if there is any special trick to get this thing back together. It just seems nearly impossible unless you have 5 pair of hands! Any tips will be much appreciated!!