2003 BF20D how to replace shift rod and driveshaft seal?

I bought a used Honda 20hp for my daughter. Good compression, starts easy, seems to run well. Doing maintenance as it has been sitting for 5 years.

While replacing the impeller, I noticed that the rubber seal around the shifter rod has cracks in it. Thought that it might not be a bad time to change out that seal, and the driveshaft seal too. FYI... no sign of water in the lower unit oil.

I loosened the bolts on the part below the water pump bottom plate. That "cover" (sorry.. not sure what to call it) comes up about 1/4", and then hangs. I was not brave enough to yank on the thing to see if it would come loose. I was terrified I'd screw up the pinon gear or do something stupid.

What is the method for removing and replacing the shift shaft and driveshaft seals going into that lower unit? My closest repair place is about a 6 hour round trip drive (I live near Albuquerque) so I like to try and do my own maintenance if possible.

Thank you for any / all advice.

Frank

Well, you are wise not to "yank" on anything.
You will need to open up the gearcase and remove the propshaft holder to access the lower end of the shift shaft.

The mainshaft will also need to be removed to replace the mainshaft seal. This too requires disassembly of the transmission.

I haven't done one in quite some time so I'm not the guy to give you blow-by-blow instruction.

The seal looking a bit "weathered" might be annoying but I'm a "if it ain't broke don't fudge with it" proponent.

If the gearcase is not leaking, I suggest that you don't disturb it as it could very well have many good seasons left before the seals leak.

I do distinctly remember NOT enjoying replacing that shift shaft seal on these. Others may disagree but that's my opinion.

90% of gearcase leaks are because of propshaft seal failing and 90% of those failures are due to fishing line or other debris wrapped behind the thrust washer and eating things up.

Frequent pulling of the prop and cleaning the shaft in addition to keeping a good thrust washer in place will keep that from happening.

Again, just my opinion.

Congratulations on getting the Honda 20. Pound for pound probably one of the best twin cylinder outboards ever made. I have a 2006.


Good luck.

I should have said that, if you're dead set on doing the deed, taking the propshaft holder out and taking a peek is actually quite easy if there's no crazy corrosion holding it in the case.

Take off the prop, remove the two bolts and she slides right out.

Again,
Good luck.

I should have also warned you to pull the propshaft holder out with the outboard tilted down so that the shaft is horizontal.

The reason for that is that there is a spring loaded shift pin at the front of the holder that will fall out into the case. The "nose" of that pin contacts the stepped "shoe" (my term) that is pinned to the shift shaft. Honda calls the "shoe" a "push rod" but it doesn't look like a rod to me. Item 14 in the parts page link below.
You can see from the parts depiction that the "shoe" needs to be disconnected from the shift shaft in order to remove the shift shaft from the case. The bend in the top of the shift shaft will not allow it's removal any other way.

"Unpinning" the "shoe" from the shift shaft is what makes this job a P.I.T.A.
I ruined several pin punches taking "shoes" off of shift rods when I was doing these seals on a regular basis. I finally made myself a "pin pusher" out of a small, heavy cast "C" clamp. Made life much easier getting that pin to start moving. Your experience may vary.

https://www.boats.net/catalog/honda.../bf20d6-lhta-2006/water-pump-vertical-shaft-1

If the shift pin does pop out, the spring will go with it. If that happens, no big deal except you will need to fish them out. And, if they get up behind the bevel gears it can be a bit of a pain.

The real pain though is taking the holder out carefully and then forgetting and letting it tilt down and having the pin and spring fall into the dirt or grass. Don't ask me how I know that:>)

Also, if you pull the holder out you will want a new oring seal on hand to put it back. Don't reuse the old seal and use a generous smear of marine grease to replace it.

Again,
Good luck,
Again.

Are we talking about the drive shaft seals located under the pump, or are we talking about PROP shaft seals?

Alan Hicks said:

Are we talking about the drive shaft seals located under the pump, or are we talking about PROP shaft seals?

Click to expand...

This is for the drive shaft seals under the pump and the shift shaft seals.

When I removed the lower in order to do the impeller, I was concerned that I saw cracking on the top side of the shift shaft seal. There is no indication that the lower has been leaking, but it has been out of the water for 5 years and I am working through deferred maintenance. I think the previous owner had not done maintenance on this in quite awhile.

"Leave it alone" might be the best solution for now, as I think that without a good diagram and instructions my confidence is not good enough to tackle this. I may just have to put it in service, and keep an eye on the oil for the first few uses.

This is a motor for my daughter, who lives near KC MO, so if it does need attention there is a likely chance she can more easily find a repair shop than I can here in the desert. I tend to be a little too OCD and I am frequently off fixing problems that might never happen.

I think I will bolt the thing back up to the power head, and give the thing a prolonged soak and look for water.

Thank you very much for the replies.

Frank

OK, I thought that was what you were talking about. Just wanted to be sure.

I don't see anything to be real shy about popping that block up to replace the seals. It's not too unusual for them to be a little sticky when removing them. Just make sure you are lifting (prying?) it up evenly so it doesn't get cocked and bind on the way out. -Al

Well, when I take off the water pump, and then remove the 3 bolts on the top of the "gear box" (for lack of better term) that plate which has the seals in it, the plate will lift up about 1/4" and then it comes to a hard stop. JGMO indicates that in order to access that area, I would need to remove the propshaft holder and the accompanying parts. Getting it apart is not the part I am concerned with

Here is a picture of the plate that is bolted back down, and the shift shaft seal which has me a bit spooked.

Top gearbox plate with the three bolts. This is the unit which only lifts up about 1/4" :



This is the shift shaft seal which has cracks in it. I suspect that I will water test it, then if no leaks I will drop the lower unit, and put some marine grease on the top side to try and limit any additional oxidation.

Your concern regarding the cracked seal is valid. Changing that one and the others is a good plan if you are able. It'll save your daughter from some potentially expensive repairs down the road.

I don't believe there's anything that needs to be done below prior to removing that "block". the hard stop is much more likely being caused by a seal caught in a grove or something.

I'm not real sure, but believe JGMO may have confused "drive shaft" for "prop shaft". He'll pop in here soon I think to confirm. -Al

Thanks... I saw a video from an Aussie (Kiwi?) guy who took a BF30 apart to change the seals, and he had to use an impact hammer to take part of it apart, and ended up bending the shift shaft in the process. Google Dangar Marine for the video. Different motor, but spooked me.

I'm old enough to be easily spooked about things that might require force for disassembly. if something hangs up, I tend to circle around it for awhile looking at it suspiciously.

-f-

I know the feeling....

Maybe this will help-

https://www.boats.net/catalog/honda...1-to-bamj-1099999/water-pump-vertical-shaft-1

and

https://www.boats.net/product/honda/19240-ZY1-C00?ref=92291f0f603d4a287700da7874deca6b4de148c4

and last

https://www.boats.net/product/honda/41112-ZY1-C10?ref=92291f0f603d4a287700da7874deca6b4de148c4

The needle bearing runs on the shiny section of the drive shaft. Note there is nothing on that shaft above that area that should/could snag much. Not until you get up into the area of the water pump key, but that would be a few inches further up from the 1/4" issue you have. Point being, there's nothing for that bock to get hung on here.

MAYBE it the shift shaft that's hanging you up? Are you able to lift up on that?

Note that the 30 in the video has a totally different design, and he was using a slide hammer, not an impact hammer. Further, he was working on a salt water motor, and judging by you're earlier pics, you are working on a fresh water motor. WAY different animals from a practical standpoint. As a snowbird, I work on Florida motors quite a bit (mostly salties) and work on all fresh water engines while in Michigan (a complete breeze as compared to the salties)....

Yup! good eye. Freshwater motor only. I can't tell if it is hanging up on the shifter or the drive shaft. But I was hoping that the pinion gear was resting on the top of the gear stack, and simply starting to raise that plate would just cause the main drive shaft and shifter to easily lift out. When I hit resistance, I panicked and set it back down.

It looks like the seal for the shift shaft presses in from the top side (from looking at that drawing of the top plate... the bottom of that plate is shaped like a "cone" for the shift shaft).

If I take it to a shop south of me, it will be a 7 hour round trip. Probably twice. Once to drop off, once to pick up. I could schedule a fishing day as there is a large lake down there (Elephant Butte). So not a complete loss

Do you know if the Seloc manual has instructions for tear-down and reassembly for this lower unit? It seems that Honda had several design changes through only a few years for quite a few of these lowers, and I am suspicious that they won't detail with good instructions and drawings for all of them.

Regards,

Frank

OK... a bit of an update. I decided against better judgement to start doing the teardown. Thank you to JGMO for digging out his manual to look at the exploded dwgs for me. I'm learning a bunch as I go, taking video and pix and will likely post a how-to thread soon. This is just a quick FYI update in case I get hit by a bus

This isn't for the faint of heart. First, in order to get the driveshaft out of the seals, you have to pull the pinion gear E-Clip off of the driveshaft inside of the gear housing. So pull the propshaft carrier out. Remove the E-clip on the driveshaft, and you can then slide the driveshaft out.

You can not slide the new seals up and over the water pump part of the shaft. The shaft is of slightly larger diameter right where the water pump key is at, and the seal will not fit over it. The seals have to "come up from below". Install them in the top of the gearbox plate, THEN push the driveshaft down into the gearbox.

Sheesh. I can't believe there isnt a youtube video on this.

There will be soon

In order to get the shift shaft removed, you have to tap or press out two steel pins that go through the shift shaft. One is a stop pin that limits the travel of the shaft. The other is the pin that holds the shifter shoe on the bottom of the shift shaft.

These pins are a BEAR. I bent two cheap punches trying to punch them out. I finally was able to get them moving with a 3/32 stanley narrow taper center punch. I had to grind that punch down in order to get it to push the pins all the way out. Putting the pins back in was much easier.

OK... More later.

I don't think anyone would really relish this job but I'm glad you are confident, competent and willing to tackle it and do it right. AND SHOOT A VIDEO!

I had completely forgotten about the travel limit pin on the shift shaft but, then, as you now know, I have forgotten plenty about doing this.

I'll be watching that video if or when my gear case starts to leak!