Leaky Lower Unit?

Hi all. So I went to check the oil in my lower unit today and was shocked to see that it was virtually all water! I refilled the LU with oil and noticed that in addition to the coming out of the normal vent opening it was also coming out of the little hole in the pic below, as well as the water pump intake screen/plate. This makes me think that the drive shaft seal, found under the impeller plate is not working. I recently did a reseal job, but it obviously didn't work very well. Any ideas what else it might be?

Re: Leaky Lower Unit?

Drive shaft, shift rod are the only two things. How does you drive shaft look? Is it smooth or roughed up?

I waiting on parts to rebuild two LU so I'm learning on these. Maybe I can learn from you.

Re: Leaky Lower Unit?

When you did the reseal, did you pull the drive shaft to replace the seals? Did you notice a groove where the seal sits? Sometimes old seals can cut a groove from lack of lube.

Re: Leaky Lower Unit?

If it was my g/c I'd have it pressure tested just to make sure where it's leaking.

Re: Leaky Lower Unit?

I resealed it about 4-5 months ago, but haven't used the motor much since then. I pulled and replaced all the old seals at the time, I don't remember seeing any major grooves or scoring, but I'll check again. I'm thinking drive shaft seal too. I'll let y'all know what I find. Thx.

Re: Leaky Lower Unit?

Any chance the wrong size seal was used...too big of a lip for the shaft?

Mas

Re: Leaky Lower Unit?

Just happen to think, my lower unit had two seals under the water pump back to back similar to the rear of the carrier bearing. Did yours? You didn't give any info on the motor itself.

Re: Leaky Lower Unit?

Sorry, it's '66 20 hp. I ordered the correct LU reseal kit from here at iboats. All of the other seals work(ed) well and there are not leaks from any of the other seals I installed. I only remember putting in one drive shaft seal, but I have heard of the back to back stacked method, but I don't think two would fit in the space. I'll report back once I have a chance to get a good look at everything. I'll probably just reseal the whole thing again. I'll try to document the whole job when the time comes in case it can be of use to anyone. I'll keep y'all posted.......

Re: Leaky Lower Unit?

There might only be one, as long as you put the lip towards the gears and not towards the water pump.

Re: Leaky Lower Unit?

Hello again all. So I was just about to order a seal kit from here at iboats, when I noticed a discrepancy between the part numbers listed in the seal kit available her and those in my parts catalog found here: ( http://www.marineengine.com/parts/v...ntage-evinrude-johnson/381415/38141500001.htm ).

According to the catalog, my drive shaft and prop shaft seals should be OMC #307563 and #302545, respectively. However, these parts numbers do not appear in the seal kit listed her on iboats (Sierra # 18-2684), which lists the oil seals as OMC parts #321788 and #321787.

Do any of you know if these discrepancies are significant, or will I be ok ordering the iboats seal kit as is? Also, does iboats sell 3M 847, or similar lower end sealant?

Thanks. I hope to start taking everything apart tomorrow and will try to have it all put back together in time for the weekend.

Re: Leaky Lower Unit?

bump

Re: Leaky Lower Unit?

Just wondering what you want the 847 for?

EDIT:

If you go to www.bestboatparts.com and search your part number, the search results show all the old part numbers, or the newer part number if applicable.

You don't need to log in or anything, just put the PN in the box toward the upper right of the page.

I use that site regularly to check for supercessions.

Re: Leaky Lower Unit?

The 847 is a thick, liquid gasket material that dries tough, but flexible and is applied to the spaghetti seal as well as to the perimeter edge of each oil seal. IT forms a watertight seal anywhere there is metal-to-metal contact like where the twp halves of the gear case meet and where the seals contact their respective housings. It's good stuff, but it costs about $25 for a toothpaste sized tube and you usually have to order it online. I just started another thread asking if anyone has had any luck with some alternatives to 847. Some folks say Permatex#2 and/or #1000 will work, but I'd like a second opinion, or two. Thanks.

Re: Leaky Lower Unit?

When I recently resealed the LU on my '73 18 hp, I used the Permatex Ultra Black and have had good success. Just make sure you seal the bolt holes with the sealant when you put it back together. I had a good leak around them regardless how tight I made them right there.

Re: Leaky Lower Unit? Now turnned complete LU rebuild. Need parts.

Re: Leaky Lower Unit? Now turnned complete LU rebuild. Need parts.

Well I opened up the LU and sure enough the drive shaft seal had popped out of place. After I opened the gear case and cleaned everything off I found that the clutch dog, pinion gear and FWD gear are damaged :/ The gear bushings appear to be seized in place too. Needless to say, I need to replace the entire set of gears. Thankfully, I have a nice new pinion gear that's in great shape, but it looks like I'm gonna need a new clutch dog, FWD and REV gears and gear bushings. I'm thinking that it may be cheaper/easier to just get a complete set of gears, but I'm open to any ideas. If anyone here in the forums has some of the parts listed below that they'd like to get rid of, PM me. My drive shaft, prop shaft, gear case head assembly are ok, but the rest is toast. According to pages 12 and 13 of my parts manual found here:

http://www.marineengine.com/parts/v...ntage-evinrude-johnson/381415/38141500001.htm


So far it looks like I'm gonna need the parts below. I'll post any more bits and pieces I may need as I find them:


Clutch Dog - 305191
FWD gear - 378079, FWD gear bearing 302496
REV gear - 307485, REV gear bushing 303997


Thanks!

Re: Leaky Lower Unit? Now turnned complete LU rebuild. Need parts.

Re: Leaky Lower Unit? Now turnned complete LU rebuild. Need parts.

On my '69 somehow the gear bushings were trashed but the gears were O.K. Couldn't find the bushings for "love nor money" ended up catching new gears off ebay.

Re: Leaky Lower Unit? Now turnned complete LU rebuild. Need parts.

Re: Leaky Lower Unit? Now turnned complete LU rebuild. Need parts.

kfa,mute point now, but may help on the reseal...did it require a socket or the like to drive the seal in the first time?..did you put any 847 aound the outter edge of the metal seal housing before you drove it in?...if the seal fit properly, about the only way I can see it popping out is the l/u was wayyyy overfilled and the sun heated it enough to expand the air space remaining and that d/s seal was the weakest point...I don't know how plausible that is even.
I'm with boobie...once you get it back together and before reinstalling...have it pressure tested...or test it yourself...12-14 lbs. for an hour would be great. I did this on the case for "ol salt"...and had leaks around 2 of the skeg screws as well as the drain gasket.

Re: Leaky Lower Unit? Now turnned complete LU rebuild. Need parts.

Re: Leaky Lower Unit? Now turnned complete LU rebuild. Need parts.

Update: Gotta love the internets. Not 20 min. after posting a WTB add on aomci.org I got a call from a guy in TX with a complete gear set I need for an AMAZINGLY good price, so I think I'll be ok for parts. As for the old seals, I thought I tapped them all in place with a socket slightly smaller in size than the seal to help seat them fully along with using Permatex (1000? if memory serves) as a sealant, and except for the drive shaft seal the rest of the gear case seals (prop shaft, spaghetti) and prop shaft bearing were all tight as a gnats @$$, so points to permatex for that. The dirveshaft seal housing was full of sealant, but the seal itself looked brand new.?.? Either I never seated it, or it somehow popped out without a drop of sealant on it.?.?.? I think it's the former rather than the latter, I'm afraid to admit :/ Who knows, maybe my prop hit something that jarred the prop shaft, which in turn caused the pinion gear to dislodge the drive shaft seal, either that or it was a vengeful Gnome and/or Gremlin. I'm leaning towards Gnomes and Gremlins b/c the prop and skeg look great and don't have any (new) marks, dents, or dings on them. I'm really not sure how, or what happened, but I'm just going to replace all of the LU guts. Thankfully, my drive shaft, impeller and housing, shift shaft and exhaust and gear case housings are all fine, but the internals of the gear case are pretty much toast. I'm gonna give aomci guy a call and order the parts so they can get here ASAP. Hopefully, the new parts and seal kit will get here at about the same time. Thanks for staying tuned. UIpdates and pics of the damage to follow......

Re: Leaky Lower Unit? Now turnned complete LU rebuild. Need parts.

Re: Leaky Lower Unit? Now turnned complete LU rebuild. Need parts.

tighter than a gnats @$$ eh? That's a new one on me! I am now wiping Mountain dew off of my monitor screen. Keep in mind murphys law while working on these engines. Ole man Murphy loves to come knocking at the most inopportune times. Good luck to ya man!

Re: Leaky Lower Unit? Now turnned complete LU rebuild. Need parts.

Re: Leaky Lower Unit? Now turnned complete LU rebuild. Need parts.

I'm just glad the 'ol girl held together long enough for me to take my uncle out on the river. I've got a nice new set of gears and seals coming for less than the price of a clutch dog alone, so hopefully she'll be happy again. For now I'm stuck with a motor that "runs" great, but just won't "go" I was glad to see the Permatex held up so well though. Always, good to learn something new. Now I just gotta play the hurry up an wait game until all my bits get here.

Btw.......I noticed that one of the little pins that holds the propshaft bearing in place is worn down flush with the gear case housing. My plan was to try to very carefully remove it by drilling it out and then replacing it with a new, SS pin of appropriate size. Does that sound ok, or should I just leave it be? Thanks again for all the help.