Honda BF50 "kicking" in reverse

[Tomfoolery]

Yeah, that’s the guy. Holds the entire guts in there. I’m afraid to change the seals in case it’s so corroded I can’t them to seal to the case again. And there’s two of them in there, one facing each way. So I just change the gear oil every fall, and keep the leg out of the water when I’m not using it.

I get it. If it ain't broke, don't fix it. Unfortunately, I usually go by: if it ain't broke, I need to take it apart and see why not...

You owe me a keyboard.

Oh, and that's how I started my mechanical engineering career, at 4 years old according to my mother, by taking her Hoover upright apart. But at least I was able to put it back together by 5 years old. More power argh argh argh!!

[DaveC426913]

If you are going to pay $3,500 for replacement of an $1,100 part; you must have one heck of a lot of respect for that mechanic

He hasn't quoted me a price.

. Also, if he could fix it by adjusting the cable, why were you hauling the boat home?

I asked him to check if I've stripped all the gears.

[Tomfoolery]

I asked him to check if I've stripped all the gears.

There aren't any actual 'gears' in the shifting mechanism - it's just a pair of dog clutches, one for each direction. The single input bevel gear, on the end of the vertical shaft from the engine, is always turning when the engine is running. It's also constantly engaged to two other bevel gears, one on the 'front' and the other on the 'back' of the prop shaft, so those two gears are also constantly turning.

The dog clutches are basically just big, crude splines with square teeth, and they slide on the prop shaft and are splined to it. When you slide the one associated with "forward" so that it's big square teeth engage the big square teeth on the output gear, it locks that pinion to the prop shaft. Since the pinion is always turning, the prop shaft is now turning, in the appropriate direction.

For reverse, that dog clutch is disengaged, and the other one is engaged. Since the other pinion is spinning in the opposite direction, the prop shaft turns in the opposite direction when that clutch is engaged.

Shifting slowly allows those teeth to 'grind', but they're not actually gear teeth. Just big square teeth like the top of a castle tower (crenellation). And you're not likely to hurt them, as they're designed to slam into engagement on the fly. Just don't do it at higher than idle speed. The gear teeth are always engaged, and can't be 'ground'.

It still sounds to me like you need to do some adjusting on the shifter rod.



Dog clutch example.

[Jimmyt]

If you are going to pay $3,500 for replacement of an $1,100 part; you must have one heck of a lot of respect for that mechanic

He hasn't quoted me a price.

. Also, if he could fix it by adjusting the cable, why were you hauling the boat home?

I asked him to check if I've stripped all the gears.

Sorry, must have misunderstood your post. Thought the $3,500 was to install a new one.

Surprised he didn't fire it up and listen to it to determine what the problem was. Didn't know you restricted the work to checking the gears.

Hope you get it squared away soon.

[DaveC426913]

opposite direction, the prop shaft turns in the opposite direction when that clutch is engaged.

Shifting slowly allows those teeth to 'grind', but they're not actually gear teeth. Just big square teeth like the top of a castle tower (crenellation).

So, gears with two teeth.

[opie]

DaveC-
Why don't you take my hard earned advice and buy a new lower unit????
Per one minute ago, I found a better price than I gave you on page 1 of this thread.
https://www.boats.net/product/honda/41005-ZY1-050ZA
The forward and reverse gears are not synchronized, meaning there is no clutch or smooth friction plate like a motorcycle. The gears are made to "clunk" into position. The shifter is "stepped" and not linear.
The slightest wear and movement of the retainer big nut and the gears won't mate properly and can't "clunk" but will just make horrible noises.
Get a dependable lower unit and a better mechanic who is not going to charge you 4 times too much for a part.

[DaveC426913]

Why don't you take my hard earned advice and buy a new lower unit????

Thanks.
We'll see how it goes over the summer first.

[opie]

DaveC,
My apologies for sounding so blunt in my post. I actually cringed and waited two days before returning to this forum out of fear I may have angered you. And what do I read just now?? Your "thank you"!
You are kind and perhaps your teeth were clenched when you wrote it.
My similar experience to yours led me to being so forceful. Briefly, I broke the aluminum housing removing the loose retainer 10 years ago. Being stubborn, I had it welded. I retapped the housing and went on a family trip and it came loose 180 miles away down the ICW. Vacation ruined. Got home by trailer and fixed it by drilling and installing 4 SS screws right thru lower unit housing. Screws came loose twice over the years. Moved to new drilled holes. Kept going for years until catastrophic failure last summer and that is when I got the new lower unit, cheap I think.
So, if you think you can manage until next summer, you are shy by 9 years. There are ways to force the lower unit to last that long. I have proved it.
But, I am just offering my experience to you and I should never judge your choices.
Happy Boating.
Opie

[DaveC426913]

No worries, Opie.

Good advice is always good advice. Seeing your experience and the research you've done will inform my decision as to how long I wait and what I do about it.

[DaveC426913]

*sigh* Boat's still at Engine mechanic's.
They don't fix trailers.

My towing service does not tow boats at all, never mind having dollies to put under the wheels.

I've reached out to my club for towing referrals.

Their response is to suggest that - if I can't get the mountain to Mohammed - it might actually be easier just to have Mohammed make a house call to the mountain.

[DaveC426913]

SeaSaw back home.

Mechanic came with a jack and checked wheels - they spun freely. Once we centred the boat a little better, we saw that the wheel had indeed rubbed right through the anti-foul paint to the 'glass. (Just a tiny patch tho).


That explains the resistance somewhat - though it doesn't really explain why the bearing would be super-hot.

I will check at next year's haulout that they centre the boat proper-like.


Since launch day at our club has been delayed till July, I'm going to splash her at a city ramp next week and we'll see how the shifter/throttle works.

[Jimmyt]

SeaSaw back home.

Mechanic came with a jack and checked wheels - they spun freely. Once we centred the boat a little better, we saw that the wheel had indeed rubbed right through the anti-foul paint to the 'glass. (Just a tiny patch tho).


That explains the resistance somewhat - though it doesn't really explain why the bearing would be super-hot.

The two issues can be unrelated. You may have an over tightened bearing, or a dry/corroded bearing - causing the heating. The hull "friction brake" could have caused the resistance to rolling. Yikes! Something I'm sure you'll watch out for in the future.

However, based on your description in your earlier post, my guess is, your brake was seized and relaxed before the mechanic checked it the second time. Brakes seem to get the hub a lot hotter than bad bearings, in my experience. I would check the brakes and bearings as a precaution.

Glad you stopped before it did serious damage. Could have been a lot worse.

[Banner_IV]

I am thinking of doing a trailer mod similar to this to eliminate the hull brake.

[DaveC426913]

I am thinking of doing a trailer mod similar to this to eliminate the hull brake.

Yep. Me too. Though I plan to secure it to the trailer runners directly. That will aid in centering the boat.
The boat is heavy enough to bend the fender out of alignment when bumping about on the road, which is what it did to mine.

[Highlander]

#1 a wheel bearing failure is a way more catastrophic an event "think " of a wheel flying off going down the road & what that could detail ? plus now u r draggin ur boat & trl frame on the ground while maybe sliding into a ditch or another car ?

#2 A brake failure "seized" is easily released thru either opening a bleeder on said brake or loosen the brake line & maybe require prying the brake caliper open . now u have no brakes but can drive at slower speed and maintain a bigger distance from traffic in front of U , allowing u to either get off the road for further assistance or drive home very carefully !. depending on ur driving skills & qualifications in my case I have a commercial drivers lic class A meaning I,m qualified to drive 18 wheelers so this would b no problem for me , but I would recommend a tow company in ur case

#3 was the lower case oil level good , was it contaminated with metal shavings & or water , how often was it changed ! was the shifter controller , shifter cable & the total mechanical shifter rods & levers checked & inspected for wear or looseness !

#4 U actually drove a boat sitting on a trailer improperly rubbing & or pushing a fender up against a tire " really" or r u saying it moved while trailering
driving an un secured load down the road is a MAJOR SAFETY driving violation & can only b done with police & proper emergency vehicles in rare exceptions & only to get said vehicle off the road in the shortish distance poss.

#5 Not sure u had the right ball size on the tow vehicle or if tow vehicle was adequate ?

#6 All ur dilemma,s r self inflicted wounds caused from lack of concern for safety , reg. maintenance, reg. inspections , do u even know what a circle check is !

#7 This is not a direct attack on u personally it just a concerned member from this site who thinks that some members on here might need & adhere to some of this advice for their & their family,s safety

#8 Now that,s off my chest , lets us all know what the final resolve of ur issue ! comes out to B ?

J