Fastwin Lower Unit Seal FAQ?

[asdasc]

I have searched for a while and can't find enough info to make me comfortable with starting work to replace all the seals on my 18HP Johnson. Is there any FAQ or Service Bullitin on it? I see many mentions of special tools and such. I would love to see a picture of the tool and which end to pound from for the driveshaft and shifter shaft seals. Also, for the prop shaft seals can I just yank them by prying with a screwdriver? Or screwing a screw into it and pulling with plyers?

Thanks!

 

[55'Fleetwin7.5]

Re: Fastwin Lower Unit Seal FAQ?

I hear ya' bro... I have replaced seals on 7.5hp and 35hp.... very similar experience. There are special tools that the shops use, but they are next to impossible to get. But, I have changed seals on 4 motors without them. I did buy a tool to drive the shift rod bearing out... they can be found on ebay. If you are reasonably handy with tools... You can do this! First time will be a drag. You will be a (sort of a pro) by the third set. There are great folks on this forum to help you through too. Hope this helps. Take care.

 

[samo_ott]

Re: Fastwin Lower Unit Seal FAQ?

You should have no problem. A standard seal puller will get the prop shaft seal out (or you can tap it out from the inside with a punch). You will need to make a simple tool to push out the shifter bushing. If you search on this site you will find it. I made one out of a part off my kids old crib! It's basically a 5/16" steel rod ground down at one end to a 1/4" bevel.

 

[asdasc]

Re: Fastwin Lower Unit Seal FAQ?

I have searched all over this site and cannot find a picture of the tool. I assume you pound it from the inside (bottom) up? Why is the taper necesary? Why not just a 1/4" shaft? Or does is seat inside the bushing, wedging in there? I would assume there is some sort of ledge that it can catch? Also, what about the seals around the driveshaft?

Thanks for the help, sorry to be so slow in picking this up. I now have a spare lower unit to get parts from, but it has some of it's own issues and the seals are shot on it also.

Thanks for the help!

 

[asdasc]

Re: Fastwin Lower Unit Seal FAQ?

I see an original owners manual on eBay. Would that work for the service manual? Or is there a big difference?

Thanks,

 

[wbeaton]

Re: Fastwin Lower Unit Seal FAQ?

Owners manual won't tell you how to fix anything. You want a factory service manual.

The tool for removing the shift shaft bushing is just a steel rod ground down on one end. The 1/4" section fits inside the bushing and the taper contacts the bottom of the bushing. When you hit the opposite end of the tool with a hammer the bushing should pop out. Here is a photo of the one I use. I've had to grind it a couple times since I find occassionally the lower unit castings slightly differ in shape around the base of the seal.

 

[asdasc]

Re: Fastwin Lower Unit Seal FAQ?

Thank you! That helps a lot. I was really having trouble visualizing what that looked like for some reason. I can make one of those pretty easily.

Next question, how do you remove the seal for the drive shaft?

Thanks again!

 

[asdasc]

Re: Fastwin Lower Unit Seal FAQ?

OK, now that I understood what I was trying to do, that was EASY!! I ended up finding an old spade bit that had a 1/4" chuck with a 5/16 shaft. I slid it thru the hole, placed a 6" socket extension over the point, and gave it a couple quick blows. It fell right out of the bottom, just like it was supposed to.

I also realize now that the driveshaft bearing is right up on top and I can get at it with a seal puller. I have a wave of relief now that I feel like I am past the part where I had no idea what I was doing.

Thanks to all for your help and patience while I built confidence.

I hope these pictures help the next guy who is afraid to try this.

 

[samo_ott]

Re: Fastwin Lower Unit Seal FAQ?

Well I certainly would never have thought about using a spade bit but then I'm sure folks would say the same about a piece from a crib! Whatever works for the DIY'er 'special' tools!

 

[asdasc]

Re: Fastwin Lower Unit Seal FAQ?

Okie dokie, apparently I am going to need a little more hand holding.

Am I doing this right? Am I using the right tool? So far, about all I have accomplished in this step is to destroy the seal and almost remove my thumb. I have added some penetrating oil and am letting it sit. There is nothing really to hold on to in order to get some leverage.

While that sits, has anyone tried using little o-rings under the 6 screw heads that hold on the skeg? I can't figure out what keeps them from leaking. It is an interesting design that allows the speghetti strap to encompass those screws, but not have any sealing on the screws themselves!

 

[asdasc]

Re: Fastwin Lower Unit Seal FAQ?

Well I certainly would never have thought about using a spade bit but then I'm sure folks would say the same about a piece from a crib! Whatever works for the DIY'er 'special' tools!

Steve's can be pretty inventive. By the way, I was reading some old posts and understand you like the pontoon boats. Here is a picture of what started it all. My wifes grandmother gave it to us. We call it the Black Pearl. All the wood was rotted, and it has set up on blocks for the past 10 years or so. I am in the middle of replacing all the wood and fixing the motor.

 

[asdasc]

Re: Fastwin Lower Unit Seal FAQ?

Well, that doesn't look like it went the way I imagined. The driveshaft seal is out now, but I gotta admit, it wasn't pretty. The inner ring of copper on the right came out first, then the outer ring. It looks like I managed to make a couple of gouges in the side where it should be nice and smooth for the press fit of the new bearing.

Should I try to take those sharp remnants out with some emery cloth? Or will driving in the new seal miraculously press those back from whence they came?

Next on the list is the propshaft seal. It is getting pretty late, I might have to wait on that one.

Any comments from anyone on things I could do differently would be appreciated. This is one of two housings I have, and the worst of them, so if all goes well, I will use it. Otherwise, this is my practice one and the other will be used.

By the way, I managed to put a little burr on the inside of the shift selector bushing while driving it out. It won't slip over the shift select rod anymore. I will have to figure out how to best align that again. If I had a good way to hold it I could use a gentle drill bit or even a reamer. Of course, I don't have a reamer....

 

[wbeaton]

Re: Fastwin Lower Unit Seal FAQ?

There are lots of different ways to get the driveshaft seal out and you used one of them. In fact, that's how I get mine out. However, you have to be very careful to make sure you don't score the wall. Take small bites with the seal puller on the lip of the seal only. A tiny block of wood can help with leverage. Of course, this info comes a little too late.

I'm not sure how you managed to ding the bushing, but all you have to do is remove the burr. Put the bushing in a vise and hold a drill bit against it until the burr is gone. The bushing only holds the o-ring in place so don't worry too much.

Don't use o-rings on the skeg screws. You need to clean them up and use a sealer on them and the spaghetti seal. The recommended sealer is Scotch Grip 847 adhesive. Use the same sealer around the oil seals (sparingly) before installation.

 

[asdasc]

Re: Fastwin Lower Unit Seal FAQ?

OK, thanks for the tip.
While we are on the subject, is there much difference between the Sierra seals and the Johnson ones? I like to support my local Johnson shop, he stocks most parts even for my '59. He said that he doesn't show a lower unit seal kit, and that he has to order all of them seperately - estimated cost $40. He did pressure test the lower unit for free, so I feel somewhat obligated to buy the seals now. I see that the Sierra kit is only about $18 on iBoats. I am thinking of buying the one online here anyway, as I have two lower units to work with and having a spare sounds like a good plan. Does the Sierra kit come with a replacement bushing for the shift shaft or just the o-ring?

Thanks

 

[wbeaton]

Re: Fastwin Lower Unit Seal FAQ?

BRP doesn't sell a seal kit so your dealer is right and the cost is about $40. The shiftshaft bushing is not a consumable item. It will not be in the kit. The bushing may be no longer available.

 

[asdasc]

Re: Fastwin Lower Unit Seal FAQ?

Hi Guys,

Thanks for the help. Well today I was able to have time to put everything together. I didn't pressure test it, but put it on the engine in a test bucket. All went well. The motor sure runs nice, starts on the second pull.

After about 4 or 5 minutes, I shut it down and all seemed fine for about 20 seconds. Then I saw white frothy stuff come streaming slowly out of the tiny drain hole just behind the impeller. We pulled it out of the bucket and drained it, all looked good. Nice clean oil without any water in it, BUT we knew something wasn't right. The Sierra kit 18-2684 came with no instructions, and the list of parts from the iBoats website for that kit, even though it says it is for my motor, doesn't correspond to the part numbers in my parts manuel. Also the drive shaft seal is actually two thin seals instead of one big one that I had. I was a little confused as to how they went in there. Maybe I have them wrong?

The only other thing I can think that would do it is the driveshaft bushing was pretty worn. How tough is that to replace? Perhaps it is so worn that the drive shaft is wobbling around and causing lube to leak out.

 

[wbeaton]

Re: Fastwin Lower Unit Seal FAQ?

That frothy oil is normal.

 

[asdasc]

Re: Fastwin Lower Unit Seal FAQ?

Really? From the water pump? Where does it come from? Is it only because I am recirculating oily water in a bucket?

 

[wbeaton]

Re: Fastwin Lower Unit Seal FAQ?

Its unspent oil and gas from the exhaust mix with water. It'll be especially dirty on a barrell.

 

[samo_ott]

Re: Fastwin Lower Unit Seal FAQ?

Yep, that's the normal goo that comes out of a 2 stroke unfortunately.