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Reverse Issue - BF 50

neversummer

Regular Contributor
I took the boat out this weekend (2007 BF 50) and everything ran great -- though I noticed a strange issue in reverse.

If I shifted into reverse and idled slowly backwards, all was good. However if I gave it some gas in reverse, I got a clunk noise and the motor would try to lift up out of the water. Never experienced this before -- ordinarily the engine is happy with a little gas in reverse -- what is going on? Something with the trim and tilt?

I should note that I replaced the water pump 2 weeks ago --- is it possible that I didnt line up the shift rod nuts correctly when I re-installed the lower unit?

Thanks!
 
Any ideas? A trim / tilt issue?

I rechecked the shift rod nuts and it looks like I reinstalled them exactly as they were before I did the water pump (took a photo beforehand) -- so I dont think that is the problem.
 
It is a trim and tilt issue. Hopefully just low on fluid. There may be some check valves that are not working right, but fill up the fluidl and see what happens. If the fluid is Pepto Bismol Pink, you have water in the system and you need to find out where the leak is, then refill the fluid (Automatic Transmission Fluid).

Check for cracks in the plastic housing that the fill plug is in. Also, check around the edges of it for a leaky seal.

Mike
 
Hi Hondadude -- OK so the fluid looked full and it was pink, but not milky, so I do not suspect a water intrusion issue.

I cannot see any leaks or cracks in the trim apparatus -- this motor has never sat in the water more than overnight and the trim system looks to be in very good shape from the outside, clean, etc. . Any suggestions on what the next step in troubleshooting is?

I have the Selec manual, but it doesnt seem very helpful in troubleshooting my symptoms -- thank you!
 
Opps! One other thing to check....the manual relief valve screw on the side of the trim unit.

See if it is tight. If so, loosen it (counterclockwise) at turn or so, then tighten it back down. Do this a couple of times to be sure that the o rings seat.

Mike
 
After confirming the trim fluid was OK, I loosened and tightened the manual release screw while letting it trim up and down a few times (to try to purge any air) but no luck --- i am still getting a clunking in reverse when revved and it pops up as if the drive does not want to stay in the down position.

Is there a check valve in the trim pump that is damaged? It trims up and down no problem, so I am confused.

Thanks!
 
Hi Hondadude, I still have the loud clunking in reverse ---- Its OK at idle, but any gas and its a problem (motor wants to lift out of the water), so I really cannot use reverse.

Do I need to replace the whole trim apparatus??

Thanks!
 
The clunking and the trim issue seem like two different problems....unless you can hear the trim doing the clunking. is the clunk there going into reverse, if you run it on a hose? What happens if you take the prop off and shift into reverse on a hose? Any clunk?

I have not had one of these apart, so I am not sure where the check valves are located.

Mike
 
I tried it last week on the hose (prop on) and I did not get any clunk in reverse when I revved it. I havent tried it with the prop off, but I figure it is the same ---- the clunk is happening under load it seems, in the water.

I should note that this was NOT happening last season (and I definitely did not hit anything) and I stored the boat in a heated garage over the winter, so I dont think freezing is an issue.

Also of note, I replaced the water pump impeller at the beginning of this season, after which I first heard the clunking on my first trip out in June -- did I screw up the shift linkage when I reconnected it?
 
I had this happen on mine, it was doing exactly as you are describing...it ended up being a bad check valve. Hope this helps
 
Good to know Skooter, thanks --- how did you go about fixing it? Do it yourself or dealer? I am trying to determine if It is something I can do myself.
 
It sounds like maybe when I changed the impeller, I did not correctly adjust the shift linkage when I was done. From the other post on this forum about BF 50 not going into reverse, I am going to try adjusting the JAM nut to favor reverse a bit more and see if that helps.
 
Problem is fixed. It was user error -- I had not correctly adjusted the JAM nut after doing the impeller, and it was therefore slipping out of gear!
 
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