Hard shifting BF90

The bf90 on my 17’ 03 Arima Sea Pace shifts way too hard. It is not the control box or the cables.

When the shift cable is disconnected at the motor everything is smooth as silk.

With the cable disconnected, it is impossible to rotate the shift shaft by hand. With the cable disconnected, the only way the shift shaft to move is to tap on the plate that the cable actuates with a hammer and a wooden drift. With the cable disconnected, the controls are easy and smooth. i.e. I'm pretty confident it is not the cables or the control box.

When everything is connected, it shifts fine into forward and reverse with no grinding and the throttle behaves as it should. It's just waaaaay to stiff.

Any ideas where the resistance is coming from? Boat is in the water now.

Thanks in advance for any suggestions.

Bill B.

Just a guess but there are 2 bushings that may be part of the problem. Items 16 & 17 in the link illustration.

Have you tried isolating the two throttle cables under the hood to check if one is stiff?

Lots of moving parts in this set up and they all have to work in unison.


https://www.boats.net/catalog/honda/outboard-by-hp-serial-range/90hp/bf90a4-lhta-2004/shift-shaft

Hopefully someone else here can give you the silver bullet answer.

Good luck

I guess I would pull the lower unit next, in an attempt to isolate the point where the issue is located.

Thanks to both of you. I'm pretty confident the resistance is 'above' the lower unit, but I will confirm when I pull the boat out next time and remove the lower unit. Those two bushings look pretty buried, and both are behind water seals. Given the access I have with the motor assembled, I don't see how I can apply penetrating oil and hope against odds that it will work its way into the bushing. Maybe I can rig up a fine syringe and inject some around the id or od of the seal for the #4 shift shaft....dump as much as I can in there.......and hope is works its way down to the #16 and #17 bushings. It can't hurt anyway.

Oh and regarding the throttle cables: with the shift cable disconnected and the throttle cables connected, the control box arm at the helm operates with ease.

Well, I don't think oiling those bushings is necessary. Being bushings they probably aren't tight but could be just the opposite...wallowed out and letting those sectors "cock and bind". I don't know
Like I said, just a guess.
I would still check those throttle cables for sticking and pull the lower end before assuming the bushings need to be hassled with. Because, as you say, they are buried and would truly be a hassle to replace.
Let's see who else weighs in on this. There are more folks here with way more expertise on these than I will ever have. Hopefully they will chime in soon for you.

Something to consider. When a cable is dry and binding when connected at both ends under load, it will often be free and easy to move with one end disconnected e.g. under no load.

Bob

I presume that with the shift cable disconnected, you are trying to rotate the shift shaft with either the engine running or with someone rotating the prop. Otherwise the clutch dogs are unlikely to align and engagement of forward or reverse will be very difficult.

Bob

You will find the shift shaft driver in the mount case is seized in the nylon bushes. Unfortunately your only solution is to remove the power head, remove the shifter and clean and or replace the bushes and seal. No other way out of this I'm afraid.

Re: Hard shifting BF90 FIXED

Problem is fixed. I'll summarize, this may help someone in the future with the same problem.

Problem: 2003 bf90 stiff shifting, not due to cable, lower end or control box.

https://www.boats.net/catalog/honda/outboard-by-hp-serial-range/90hp/bf90a3-lhta-2003/shift-shaft

I suspected the bushings that #4 and #8 run in were the source of the extra resistance. I removed the seal and seal holder (#29 and #11) and shot it full of pb blaster......I did this a few times and let it set overnight. The boat was in neutral when I took it apart and I noted as best I could the radial position of the shift shaft # 8. That's important, because you can't see at all how it engages with #4 upon reassembly. It's very easy to install 8 and think it's engaged with #4 and it's not (ask me how I know lol). I put a long zip tie on the splined part of the long shift rod that goes down to the gearbox. That allowed me to see whether or not the shift rod moved when i jiggled the shift shaft 8. (because the long zip tie is sticking out far enough that I can see it while working on the front side of the motor) Once I was convinced 8 was engaged with 4, i slide the new seal and seal holder in place, periodically checking that the gears were still engaged. Buttoned it all up an voila, shift smooth as butter now. The proper way to do this is to tear the motor apart so you can access the gears and properly clean and lubricate them......that wasn't an option in this case so I took a chance on a bush-fix and it worked. Make sure you are in neutral before you start and your control box is also in neutral.

extra: I drilled a small hole in the face of seal #29 after I installed it in the seal holder and before I installed the seal holder. In that hole, protruding into the case, is the red tube that comes taped to the side of WD40/PBlaster etc.. cans. It's a tight fit. So now I can lube that area once a year and keep things moving smoothly, I just connect the can to the red tube and give it a squirt. I'm guessing that maybe one of the seals is going bad and allowed some corrosion to form on the shafts where they go into the bushings. Kinda like what can happen to the starter gear and ends up preventing it from shooting out and engaging the flywheel. That's just a guess. Anyway, I feel better being able to maintain some lubrication to #4 and #8

Cheers.