HELP!..I'm screaming at Lower Unit...40hpMerc.

[Dmzhmdepo]

Am trying to get the lower unit off of my 40hp 74 Merc. Following the manual, can get the rear to come loose about 1/2 inch but the front seems to be hung on something and won't budge pase 1/8". Do not want to break anything and am wits end...Anybody know what I might be doing wrong? Am going per the manual. AAAAHHHHHH!!!!!! Thanx. I needed that. Dmz...

 

[petryshyn]

Re: HELP!..I'm screaming at Lower Unit...40hpMerc.

if your sure you got all the bolts out....the driveshaft and crankshaft could be married together with rust. You could try prying with 2 large screw drivers or pry bars (one on each side) and evenly pry the housing away from the leg. Pry closer to the front of the housing right above the vent/fill screw. Carefull how you pry...not to damage the flanges...<br /><br />***** Be darn sure you got all the nuts and bolts out first!!!<br /><br />good luck!<br />

 

[Dmzhmdepo]

Re: HELP!..I'm screaming at Lower Unit...40hpMerc.

Thanx Schematic.... but I have been tugging, pulling, prying, and beating on the darn thing for hours and dont seem to be getting anywhere with it. It still seems to loosen about 1/8" all around but hangs up there. Am afraid of fracturing the housing if I keep this up. The manual says something about a lock nut by the front of the gear housing near the mounting stud on other models. Don't see that on mine. Am at wit's end.. I do have all the nuts off, that I know about.

 

[Trent]

Re: HELP!..I'm screaming at Lower Unit...40hpMerc.

You did remove the trim anode "fin under the cavation plate"? Its got a bolt hidden under it.

 

[Dmzhmdepo]

Re: HELP!..I'm screaming at Lower Unit...40hpMerc.

Thanx Trent, but the nut under the plate and the nut under the cav. where the first to go. I loosened the 2 side nuts on the gear housing and proceeded to try to loosen. The rear of the unit (over the prop) opened about 1/2" , but the front is stuck at 1/8" and won't budge. my arms are sore from trying.... Thanx for the idea though! I appreciate it. Dmz.

 

[petryshyn]

Re: HELP!..I'm screaming at Lower Unit...40hpMerc.

Before you break something, verify that the shaft is frozen in the crank....to do this...<br /><br />>resecure the lower unit with atleast 1 bolt<br />>gently pry the flywheel up and down to observe end play.<br />>remove all lower unit bolts and have someone maintain a pry pressure downwards on the lower unit while you recheck for flywheel end play.<br />>if end play is still there, lower unit stuck on something else.....shift shaft, other nuts and bolts etc....<br />>if end play gone......driveshaft and crank are married....<br /><br />

 

[G DANE]

Re: HELP!..I'm screaming at Lower Unit...40hpMerc.

I had succes with this method once - if you are SURE the problem is drive shaft rusted to crankshaft: Open to max gap in the back.<br />Find two of some metal things same size as the gap at the middle or a bit in front of the middle. Squeze the two bits between lower unit and leg. Put the back or two back bolts in again ( you might have to find a longer bolt ) Then fasten 2-3 turns. Each turn will pull shaft out, or you will loose waterpump housing - which is a cheap way to get out.

 

[Walter]

Re: HELP!..I'm screaming at Lower Unit...40hpMerc.

One problem here is you keep posting new topics...although the issue (74 Merc 40 hp) is the same. I'd have to scroll down and read all the previous posts to know what you have and haven't done...or what has or hasn't been suggested. From now on, how about posting everything to one topic so we can just scroll through each thread and get the whole story?<br /><br />Is your shift lever in forward gear??<br /><br />Walt

 

[Dmzhmdepo]

Re: HELP!..I'm screaming at Lower Unit...40hpMerc.

Schematic and G Dane. Thanx guys, I will try anything at this point and your help is what I count on. Thanx for reading and helping. DMZ.

 

[Rex]

Re: HELP!..I'm screaming at Lower Unit...40hpMerc.

JUST TELL US HOW MANY NUTS BOLTS THAT YOU<br />HAVE OUT?<br />YOU COULD BE MISSING ONE.<br />REX A. HUBBLE

 

[kenh1010]

Re: HELP!..I'm screaming at Lower Unit...40hpMerc.

I not a machanic but could it <br />be the shift rod screw or cotter pin?<br />Try putting if in gear and see if it drops <br />a little more so you can see in there.<br />I remember doing that to my old Chrysler 35.

 

[12Footer]

Re: HELP!..I'm screaming at Lower Unit...40hpMerc.

I had sucess on the same make/year/model by loosening all the bolts, but leaving them on.<br />Then I cranked-up the engine long enough to change gears,forward to reverse one cycle,then quickly shut it off.<br />The l/u slid-off like butter. I know the engine is still out there, running, but am unsure if this can do any damage..But I was (like you), at my witt's end with the ##%^ thing. <br /><br />

<br />Before you try this, you can also try loosening, bumping the starter,forward and reverse with the engine off. It didn't help me, but it's worth a shot before the "last straw".<br />Good luck, and let us know how you do get it off.

 

[Dmzhmdepo]

Re: HELP!..I'm screaming at Lower Unit...40hpMerc.

Guys, I really appreciate all your help. I have tried everything you have suggested. I'm thinking ANCHOR here. <br />I have taken the trim tab off and removed that nut. I removed the nut under the cav. plate. I have loosened the two nuts on each side of the gear case, but not all the way since you must lower the unit to get them completely off. There is no play in the flywheel. It just opens 1/8th" and thats it. My manual says nothing more. It should be off by now. I do appologize if I am not posting these correctly. But, I am totally frustrated and about to give up for the nite. Thanx again .....to everyone who has been kind enough to share their thoughts.

 

[petryshyn]

Re: HELP!..I'm screaming at Lower Unit...40hpMerc.

DMZ<br /><br />don't give yet, we've only started!!<br /><br />do you have access to a slide hammer?

 

[Dmzhmdepo]

Re: HELP!..I'm screaming at Lower Unit...40hpMerc.

Schematic. Do you mean the tool that body shops have to pull dents and things? If so , sorry - no I don't.

 

[petryshyn]

Re: HELP!..I'm screaming at Lower Unit...40hpMerc.

do you have a auto supplier that lends or rents out tools......"axle puller slide hammer"?

 

[Dmzhmdepo]

Re: HELP!..I'm screaming at Lower Unit...40hpMerc.

i'm sure I can get any tools needed, just need to know what I need and how to use em. Thanx for any help....

 

[Stream_fisherKY]

Re: HELP!..I'm screaming at Lower Unit...40hpMerc.

For what it's worth i'm rebuilding my engine currently too. It's nearly the same age but a completely different size which may make a big difference. I found in disassembly that the manual gave information that you had to "read between the lines" to get. When it came to the lower unit i had to loosen all the bolts, and then shift the engine into forward gear. Once in forward (or bout half-way there) i had my friend hold the shift in place and then tapped on the front part lightly with a hammer and a block of wood. It took several minutes to work it loose but eventually it fell. If that doesn't work for you use my dad's method and grab two long screwdrivers and pry that beast outta there.

 

[petryshyn]

Re: HELP!..I'm screaming at Lower Unit...40hpMerc.

Yo DMZ.....<br /><br />If you're sure you got all the bolts out, and the driveshaft is actually stuck in crank.....this may jar it loose. If you have to hit many times, you may want to inspect the lower driveshaft bearing for damage. Jaring it will give better results than a straight pull. Use 2X4's and 3/8" bolts and tighten them up good. The tool is a slide hammer used for pulling axles....<br /><br />Good luck! <br />

 

[alcan]

Re: HELP!..I'm screaming at Lower Unit...40hpMerc.

Hey schematic <br /> Since the prop is also stuck. What would happen if he cut that bugger off and drilled out the gear case nut. Used the slide hammer to pull prop shaft and bearing carier. Then remove nut on pinion gear? Would the gear case slide off sacraficing pump housing (as dane suggested)? Then apply slide hammer directly to drive shaft.<br /> Dmz dont give up. I had several of these (stuck drive shafts)and not to many sucsess stories. Once in a while you get lucky. keep the faith,good luck.