Help Removing Lower Unit on 64 Evinrude BIG TWIN

[AlexeiVT]

Hello again (been several years since last post, and I'm back at fiddling w/ this motor).<br /><br />I'm running into some difficulty removing the lower unit, so that I can gain access to the water pump housing for impeller replacement. First, I'm confused at just what I have to remove, and secondly (figuring I'm removed the proper things) am unsure why it just doesn't seperate.<br /><br />I fancied myself as somewhat mechanically inclined, plus I have referenced later years Clymer's manuals, among several others, but still don't seem to be getting the info I need.<br /><br />I've removed 6 bolts (3 on each side, underneath the anti-cavitation plate)...are these the ONLY bolts, and ONLY 6, I need to remove?<br /><br />I've removed the access plate (as well as the plate behind it) on the right side of the motor, and loosened up the shift linkage bolt...does the bolt need to be completely removed, or just loose...as it is, it's finger loose, yet when I move through the gears, the rod still seems firmly attached and moves as if it were firmly bolted.<br /><br />Now, here's where some confusion comes in...right above this lower most portion of the motor (the part that gets filled w/ gear lube and has the top fill hole) there is also another segment of the motor, about the same length, that is bolted in place (it's underneath the removable shroud). This part is again held in w/ 6 bolts (3 on each side) as well as, so far as I can tell, one more very inaccessible bolt at the back of the motor (the head is up inside, and w/out some facily bent wrench, the whole engine covering would have to be removed to get at it)...is it this portion that I need to try to seperate things, or the lowermost portion?<br /><br />I've tried both, w/ absolutely no success...the bolts came out easily enough, but no matter how hard I wrestle w/ things, I can barely see light between the mating surfaces (and when I do, it's only at the front portion, the aft portion of the mating surfaces don't even seperate).<br /><br />I'm not certain what's reasonable force at this point...I was leery about inserting screwdrivers w/ excessive force, and risking nicking what I assume to be surfaces that should remain flat.<br /><br />What holds things together up in there...should it really just drop loose?<br /><br />Does this sound like a scenario of the dreaded gaulded or corroded splines keeping things together...and if so, what's the plan of attack.<br /><br />It's a heavy enough 40 hp '64 Evinrude BIG TWIN...if removing and flipping it is the only reasonable option to soak some penetrant in there, I'll reluctantly entertain that idea...but even if that IS the case...how on earth would one get penetrant where it needs to go, since you can't see up there, much less access it....does this call for completely removing the outer thin aluminum housing so that you can see the cast part of the motor.<br /><br />I know this is lengthy, I apologize for that. Just hoping to get some simple straightforward answers, and apprise any help of where I'm at and what I've tried (and failed w/) thus far.<br /><br />Thanks for any and all help...hoping to get on the water by the weekend (I live in NJ, but my boat is in CT, so figuring out what to do when the motor isn't on hand, has been a chore...but now I finally have a day or two to crack at it). Thanks, AlexeiVT

 

[lark2004]

Re: Help Removing Lower Unit on 64 Evinrude BIG TWIN

I think you missed a bolt. If you remove the shroud that covers the outboard leg, you will see a bolt that goes down into the gearcase. You need to remove this one as well

 

[itstippy]

Re: Help Removing Lower Unit on 64 Evinrude BIG TWIN

There is another bolt and it's hidden behind the external housing that makes Big Twins so quiet running and beefy/cool looking. That extra segment that's bolted in place underneath with the extra 6 screws is a 5" leg extender to make your motor a longshaft. It stays where it is. You do have to remove the back portion of the external leg housing though -it's the big metal shroud with the handles on it for tipping the motor up. Six screw on each side. Comes off easy. Once it's off you'll see the bolt you need to get out. It's a big one and long, too, since it goes all the way through the 5" extender and into the lower unit.<br />The shift linkage needs to be looser in its clamp than it sounds like yours is. I would spray it down with WD40. Careful about prying around in there, those brass couplers strip easy.<br /><br />Follow the manual. I don't know about Clymer's - Seloc's is pretty good on the Big Twin lowers. Be patient putting it back together. Here's a post on re-installing; ignore the stuff about shift wires (mine's electric shift). The shift rod will give you your own fun. A reinstall on a long shaft will be a challange!<br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=28;t=034767#000000

 

[itstippy]

Re: Help Removing Lower Unit on 64 Evinrude BIG TWIN

Lark ya beat me to it.

 

[lark2004]

Re: Help Removing Lower Unit on 64 Evinrude BIG TWIN

sorry <br /><br />I should be getting ready for work!

 

[AlexeiVT]

Re: Help Removing Lower Unit on 64 Evinrude BIG TWIN

Just for some additional clarification (and a big thanks so far for the additional information so quickly).<br /><br />The location of the additional bolt I need to remove...<br /><br />Is it located at the TOP of the extension unit...When I look at the extension, it has 6 bolts in roughly the same positions as that on the lower unit.<br /><br />But, when I remove the shroud that goes over the extension...right up on top, just beyond reach, is an additional 7th bolt.<br /><br />This 7th bolt, the head can only be accessed from the top (whereas, all the other 12, have the heads accessible from the bottom).<br /><br />Is that 7th, top accesible only bolt, right at the rearmost portion of the motor, the one that's still got to go?<br /><br />I tried to gain access by removing the shroud that goes from the back half of the extension, up to the back 1/3 of where the engine cover seal goes (I hope I'm describing this clearly...as that's the only piece left to expose the "guts" of the motor...basically the thick rubber seal that mates between the removeable engine cover, is at the top of this shroud).<br /><br />Any hints for removal...unlike the 6 hex bolts...these phillips head screws are fairly well bodged,and pretty happy where they are (I'm thinking Vice Grips at this point, since I can't get a good bite w/ enough pressure w/ a screw driver).<br /><br />I'll give it a try...maybe there is hope yet.<br /><br />I seem to remember someone once saying that these older motors were easier to work on (and that's what I've been telling friends/naysayers)...looks like they'll get the last laugh, especially after reading the link on reconnecting the long shaft and dealing w/ the water tubes.<br /><br />Perhaps worthy of another thread...but I also have a Simplex shifter, that I cannot get to function properly when the engine has any sort of RPM's in it. (If the motor is off, I can get Forward, Neutral, and Reverse). BUT, when the motor is running, I obviously can shift from N to F, but after that, I cannot get it to shift back into N while running at even minimal idle. Not that it's super critical, but it'd be nice to have. What I've been doing, that works...is to rev it up a bit, cut the gas, then shift into N before it stops firing completely, and then I can get it to N and rev it back up.<br /><br />Thanks again, you've all been a help already, and helped me to sleep a bit better w/ ease, knowing what I have to awake to tomorrow.<br /><br />I've tried searching the archives...invaluable source of info, and at this point I can almost picture in my mind what I need to do...but, alas, my projects always seem to run into a hitch.

 

[itstippy]

Re: Help Removing Lower Unit on 64 Evinrude BIG TWIN

"Is that 7th, top accesible only bolt, right at the rearmost portion of the motor, the one that's still got to go?"<br />Yes. On the top, rear of the extension.<br /><br />"Any hints for removal...unlike the 6 hex bolts...these phillips head screws are fairly well bodged,and pretty happy where they are (I'm thinking Vice Grips at this point, since I can't get a good bite w/ enough pressure w/ a screw driver)."<br /><br />First, use a pick to get any paint out of the phillips slots. If the phillips bit doesn't seat properly in the slot because there's paint in there you will strip the screw and use bad language. Second, there's a cheap, wonderful tool called an "impact driver" that you can get at NAPA or similar parts store, or a decent hardware store. These are great! They look like a thick steel screwdriver handle. You fit a bit into one end, put it on the screw, and hit the back end sharply with a hammer. It pounds the bit into the screw slot and turns it at the same time. They're adjustable for clockwise or counter-clockwise rotation. Get one of these things! If those screws holding the shroud on have stripped heads already from previous attemptes to get them out you can use a (quality) vice-grips. The screws have nice big heads on them so you can get a good grip.

 

[lark2004]

Re: Help Removing Lower Unit on 64 Evinrude BIG TWIN

I replaced all mine with stainless caphead screws (Allen key). Cleaned all threds with an intermediate tap, and coated all threads with non-hardening sealant (permatex #3).<br /><br />These shouldn't ever really get stuck that bad, as they have to come off every time you replace the water pump.

 

[CATransplant]

Re: Help Removing Lower Unit on 64 Evinrude BIG TWIN

"I've removed the access plate (as well as the plate behind it) on the right side of the motor, and loosened up the shift linkage bolt...does the bolt need to be completely removed, or just loose...as it is, it's finger loose, yet when I move through the gears, the rod still seems firmly attached and moves as if it were firmly bolted."<br /><br />Yes, that bolt has to be completely removed. It passes by a grooved area on the shift rod. Once it's removed, the upper shift rod can come out and the lower unit can be removed.

 

[CATransplant]

Re: Help Removing Lower Unit on 64 Evinrude BIG TWIN

Here's a very good thread on replacing the impeller in a Big Twin. Paul Moir and I both entered step by step instructions here. Everything is covered.<br /><br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=28;t=032100

 

[rodbolt]

Re: Help Removing Lower Unit on 64 Evinrude BIG TWIN

if your rear cowl screws are to stuck, here in the salt pond they always were. you can take a small cutoff wheel and make an inverted V shaped notch to access your seventh bolt. speeds up the process and save a lot of time drilling.<br /> looks a bit funny but works well.

 

[AlexeiVT]

Re: Help Removing Lower Unit on 64 Evinrude BIG TWIN

THANK YOU SO MUCH EVERYONE...and a few final questions...<br /><br />I really am grateful to all you contributors, for salvaging my weekend...the information provided, was just exactly what I needed but was unable to locate despite the ways I tried to search for it.<br /><br />Things are almost all back together...but after reading the tutorial (after the fact), I now still have a few new reservations I'm hoping can be put to rest.<br /><br />You mentioned NOT to remove the driveshaft from the lower unit (I ask WHY NOT...specifically because I ended up doing that...should there be cause for concern?) I removed it, sort of inadvertently, since it readily came up, and I just aligned the impeller cutout/key/and groove in shaft (I had no problem just placing the impeller in the housing, and figured it was an easy way to line things up)...when it was together, I just wiggled the now attached pump housing and shaft, down home in the lower unit.<br /><br />So what's next to address on the driveshaft...things seem to be engaging, I can move through F,N,R and turn the prop shaft (and consequently the drive shaft)....did I somehow escape a potential problem, or is there one still potentially lurking (anything to calm me at this point would be great, since I'm only a few screws from calling it finished).<br /><br />I also didn't apply any additional grease to the top of the splines (they still had some evidence of lubricant), nor did I replace that top O-ring, just inspected it and cleaned it, and reinstalled it (I know these procedures for the next time, so it should be a snap, and I'll replace them then...so far, in the 8 or so years I've had the privelage of working on this boat, it's only been out on the pond about 4 times...hopefully all is good to go for a few more outings in the pond this summer/fall...but if I "should" go back in to address anything I've done wrong, I am reluctantly willing to crack it back open and address the issues).<br /><br />My boat, named the SEA SNOT II (just in case I don't infringe upon anyone who has the "original" number I) is just about ready for another outing.<br /><br />Thanks again...please give me your suggestions as to what to be concerned about, having withdrawn and reinserted the driveshaft from the lower unit. <br /><br />(I've got another manual shift question as well, but I'll start another thread for that).

 

[itstippy]

Re: Help Removing Lower Unit on 64 Evinrude BIG TWIN

You're OK. Often when you accidently pull the driveshaft out the pinion gear in the gearcase flops over to one side and you can't get the driveshaft back in. Gotta pull eveything apart to line them back up. You were fortunate, the pinion gear didn't flop, you got the shaft back in fine. It's hard on the oil seals to pull that shaft in and out too, so keep a good eye on your lower unit oil for milkiness (you should do that anyway). Re-greasing the upper splines is to prevent the dreaded "gaulded or corroded splines" you refer to in your original post. I slather 'em with grease, but if they had residual grease on them and no sign of corrosion or damage you'll be fine. If the rubber o-ring was in good shape than that's OK too. I replace them, but I've also dropped lower units where the rubber o-ring disintegrated years ago and no damage done. Again, the desire is to keep the upper splines goobered up so they don't corrode together. Are you running in salt water environment?