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Honda BF100 10HP , lower unit removal methods - HELP

M

mroman59

Member
Hello, I tried to drop lower unit from my outboard and it appears the shift rod joint (at shift arm) in engine compartment must be removed from the shift rod. The diagram in book is showing threads. Of course I do not know how to get it off. It is getting hung up at the rubber grommet. It appears that you may have to disconnect the upper extension case and remove the lower unit from the upper case after it is entirely removed. Is this how it is done?

I was reading somewhere that you have to turn the case and leave the shift rod joint in place and count the turns. Unfortunately, I have disconnected the shift rod joint from the shift arm and I was spinning the shift rod. I don't know if I was turning just the shift rod joint on its threads or was it spinning from below. I turned it from the top and it stopped, but I did not count turns.

The question now is, do I try to reassemble it at the top with the pin in and then disconnect the upper case/lower case and spin and count turns? If so, how do I get it back to where it should be? I assume that I will have to get it in a position where it is in neutral and then see if I can shift it in forward and reverse.

I am trying to lower the unit to replace the gear shaft seal and the seal underneath the impeller. I have water getting into my lower case. When I laid my motor on its side, I noticed oil draining out the water intake tube at the bottom. Then when I stood it up more came out. When I run the motor in a tub excessive grease film appears in the tub.

Any help would be appreciated. If anyone has a mechanics book with step by step instructions for best removal , that would be appreciated.
 
Hi,
Sorry you're having troubles. But, you'll get it ok.

You don't have to remove the extension case to take the gear case off.
While you can do it that way it's much simpler if you don't.

You do have to take the shift linkage pin out and spin the upper link off so that the shift rod will slide through the oil case (the tub the engine sits in) and the extension case and out once you remove the 5 6x40mm bolts that hold the gear case to the bottom of the extension case.

When you go back together, shift the transmission into forward and also put the shift lever in forward.

When you get the end of the shift rod up where you can access it in the oil case, screw the rod end link on until it gently bottoms out on the rod. Then, back it off 4 1/2 turns. This should put it in the position so that it will slide into the clevis and have the holes line up so that you can insert the clevis pin and then the cotter pin.

The gear case can leak at the shift rod seal and propshaft seal.

Outboard shops use a special adapter screwed into the oil fill hole to pressure test the case and pinpoint leaks.

I hope this helps you. Ask all the questions you like. Someone here will usually have the answer.
 
Thanks for your reply and help. I found this same problem posted on another website last night and just did not know I could start screwing that shift rod joint off from the top. The book shows threads and I was spinning it and thought I was spinning the shift rod. Boy do I feel stupid. Now to another issue.

I am not able to move the shift rod up and down freely like I did with my hand when I first removed the shift arm in the engine compartment.

1. Can you move the pinion shaft and make something come apart inside where the shift rod connects? If so, how do you get it to align up again? Do I have to take propeller prop off and gears to fix that?

2. After cleaning I inspected the pinion shaft and by accidentally pulling it out a 1/2 inch, I noticed that the shaft, which appears chrome plated, is rusting and the chrome is coming off right where the seal surrounds the shaft. Is that going to be a problem and does that require being replaced? Many of these parts for this engine are obsolete and you can not buy them.

3. My intent was to replace the water seal below the water pump and the water seal around the gear shift rod, only because I believed that water was getting into the extension case and leaking onto the ground when the engine was sitting on its side (storage). I know there is a seal behind the propeller, but I was not planning on changing that. Do you recommend changing that at the same time as the other seals?

4. Can any of these seals replaced can be purchased from local stores if parts are not available or even the same dimensions? The seal no. for the BF100 is B100-1003429.

5. I have a shop manual from Honda with the engine, but it is not very detailed
I heard that Clymers makes a OK book for more detail. Does anyone have any recommendations?

Thanks, Mike
 
Hi,

Well, if you DID rotate the shift rod, it's possible that the little "shoe" got a little sideways with the shift pin and bound up. If that's the case, just try gently grabbing the rod with pliers and sort of "jiggle rotate" while jiggling it up and down at the same time. You want to do this gently, as I said before, as well as trying not to have the pliers slipping and marring up the rod.

But FIRST, just try moving the rod up and down while rotating the propeller. The clutch may just be bound on the shaft if you weren't turning the prop before. You should ALWAYS rotate the prop by hand when "dry shifting" the transmission with the engine not running.

As far as parts, are you familiar with boats.net? They are the "go to" suppliers of DIY outboard guys. They offer pretty much all the genuine Honda parts still available at much better prices than the dealerships.
I looked there and it seems all the seals are still available.

The pinion shaft being deteriorated like that could prevent it from riding properly on the seal lip. Not good. When I looked on boats.net the availability for pinion shafts is "spotty". Some models have replacements in stock for around $85 and some model's shafts are listed as unavailable. Although, there may be some interchangeability.
You might need to get someone at boats.net on the phone to check dimensions for you.

As far as changing all the seals and prop holder oring at once, yes, I recommend it. That stuff is all the same age and one is just as likely to leak tomorrow if it's not leaking today. But that's your call.

I don't have much faith in the Clymer and Seloc manuals but, yes, the Honda offering for these leaves much to be desired. I have been able to get by with mine but I'm a big fan of "better" as long as it doesn't break the budget.
 
Thanks again. I tried rotating the propeller while working the shift rod. No luck but I'll try some more.

I was checking for replacement pinion shafts but could not find any available, all the sites I visited said obsolete or not available. The part I am searching for is 41121-881-000. Yes the do run around that $85. I do see a new one on ebay for $179 or best offer. I am not sure that I have the correct part at this time. I got the part no. from Honda website. My motor was made for a sail boat, I believe. The length from the screw clamp adjusting rod to the cavitation plate is 23", little longer than a long shaft. If you see a price at a website that appears to be available, I would appreciate it.

I will have to remove the pinion shaft to determine its dimensions.

Thanks again for your help
 
Im back. Thanks again for the information. I see the link and the 030 ending. It is also being sold on ebay for $86, sounds more reasonable. I was wondering how you found the part. Were you looking based on my serial no. B100-1003429? I was looking under BF100 LA.

I broke down and removed the propeller and gears in the lower unit to see the hook end of the shift rod and how it connects. I did notice an F stamped on the shifter clutch. I speculate that has something to do with helping install and perhaps means forward. Do you have any instructions for installation and getting the shifter rod in place? I believe that the shifter rod should move up and down quite easily (from forward , neutral and reverse). Am I correct.




 
I was taking a look at installing my propeller shaft. My book says "when removing and installing make sure that the transmission is in forward" that sounds like if you remove and install the shaft while the lower unit is connected (going by words and pictures). Does that mean that you have to attach the lower unit and then install propeller shaft? I know you mentioned that shift rod joint should be screwed on until it stops and backed off 4 1/2 turns. Is that needed to be done and attach the lower unit first so that every thing lines up to install the propeller shaft? Seems strange, but I am wet behind the ears and a boat mechanic in training, LOL. If you believe a Cylmers or Seloc book is needed, I will go get one. If you can walk me through it, great. I noticed that the clutch is spring loaded and maybe after assembly the shift rod can be moved by hand through the gears, but maybe I was dreaming. If the shift rod is suppose to be tight and not freely moved with hand, that is where I am making my mistake. Thoughts are appreciated.
 
OK , I think I figured it out, i.e. how to get that shift rod back into place. Since I think I know how, they I will begin to buy the seals and other parts I need and go from there. If I need further assistance, I will continue on this thread or start a new one to make it easier.

Thanks again.
 
Jimmy,

The 030 in this case is not necessarily a super cession for the 000 part number that Mike found.

My parts program does not recognize the B100-1003429 as a valid frame serial number at least, in the USA. If it were BF100-1003429, then things start clicking.

Mike
 
If the serial number begins with BF100 then the parts should be looked up under model BF100 then SA for 15 inch transom height or LA for 20 inch transom height.

It appears that is how Mike is looking up the parts.

If so, then the 030 part is not the correct part.

Mike
 
Yes, this has been a problem since I started looking for parts for the motor. A local boat shop tried looking up parts for me and said he could not find anything and Honda does not put out any parts diagram for it, supposedly because the B100's were the first units to come to the US or perhaps were made for Canada. I am not sure which is the case. The transom is 23 inch, which I am speculating that it was made for a sail boat. I took a bracket and mounted it to my boat to raise it 3" to get it at the right level. The engine looks very clean and looks like it was never worked on and runs good. The lower unit, seems very good, just seals going bad and the drive shaft wearing. Regardless, I have been finding that many of the parts for the BF100 are the same, when I look at the photos and photos of parts on eBay. I emailed some some guys selling the shaft on eBay, one who is selling the 000 and the guy selling the 030 part. There no. of splines and length of shaft appear to be the same at this point, so I am not sure why the different part number. If I buy one , I will try to match up by dimensions, rather than worrying about part no.

If anyone has further knowledge of how I can get the proper manual or parts diagram for my serial no. , I would appreciate the help. Maybe call some Honda dealer in Canada and see if the B100 was made for them.

Mike
 
Thanks Mike....yes, I actually figured out on my own that the 030 is not a direct replacement for the 000.

Looking at the two it becomes obvious that the 030 doesn't have the hole for the unavailable impeller drive key! And, studying things further suggests that the 030 may not work with the vertical shaft as it is a different part number than the one mated to the 030 pinion. And it is also unavailable.

As far as you, mroman59, noticing that many parts are interchangeable, yes! As a matter of fact, the 030 pinion is used on most of the 10hp as well as most of the 7.5hp AND on all the BF 8A models up to around 2004! Just not on a handful of old 10's (yours) and 7.5hp. Dang!

So, I got to thinking...."could he retrofit a new vertical shaft ($74) and use the 030 pinion ($85) along with the available impeller and housing ($16.01 & $70.17) and be done? Pricey I know but these are such GREAT outboards!

But....nope.....his 23" "XL" negates doing that easily. Yes, you could cut and splice the new vertical shaft but unless you have some pretty fair skills and tools, that would probably need to be done at a good driveline shop to get reliable strength and balance.

So, if it were me, I would try to determine if my impeller housing is serviceable and if the drive key is in good enough shape that I could use it as a template for making a couple of copies. The impeller for the 000 pinion is available.

Then, it's a matter of finding a good machine shop that can have your old pinion shaft cleaned up and brought back to correct dimensions using metal spray and chrome applied. Still pricey but should last for many years. It never hurts to ask anyway.

Good luck.
 
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