BF50A6 - Engine will not stay in tilted up position while left over night

After boating, I leave the boat in my slip with the engine in full up tilt. Several days later I return to find the motor down in the water. It does not happen every time I use the boat, but more so than not. I checked the manual release valve and it is fully closed. It does work though. Otherwise, the tilt and trim works properly. How can I determine what is causing this problem? Troubleshooting steps? Thanks in advance!

Someone else may have a better answer for you but I'm responding because no one else has as yet and this will keep your post "live" one more day.

The bottom line is that these trim/tilts are just plain hard to troubleshoot......hydraulically......especially when the outboard is on a boat in the water.

You have already done the main...and easiest...check which is the manual valve.

There are a couple of possibilities.....air in the system or, the internal bleed check valve is going bad or sticking open. Since it's so intermittent, I would guess it's the valve sticking.

Air in the system would indicate a leak of some sort. It could be pulling air through the ram seal. But, again, proving that is tough. Even properly checking the fluid level is difficult in the water and so finding bubbles of air in the fluid may prove impossible. If you can get to the reservoir fill plug and make sure the unit is full of fluid that's about all I would think you could do.

If it's full, then it's probably the check valve. If so, I would just tilt it up and use the tilt lock and not worry about it. The check valve wasn't really meant to hold the outboard up indefinitely anyway and the tilt lock SHOULD be used for trailering or uptilted storage.

Good luck.

Thanks jgmo.

There are no external leaks that I can find, and I had it in my driveway for a week before putting it back in the water yesterday, so I'm not thinking there could be air in the unit. I will continue using the tilt lock, and the next time I have it out of the water I will then check the oil level.

Again, thanks for your input!

Don

You didn't say what year your outboard is but the trim units can start giving problems at 10 + years. Honda sells dedicated repair kits for these and I have successfully rebuilt a few. MUCH less expensive than a new assembly but taking one of these apart and getting them back together properly isn't for everyone. It's not rocket science and there's no need for any special tools unless you need to re-seal the piston. But, CLEANLINESS and attention to detail is required. A digital camera helps a lot too.

As long as your unit is topped off with fluid and there are no leaks to be found, I see this as a minor issue and I would keep using it as long as is possible. You might get another 10 years out of it by just remembering the tilt lock.

Its a 2006 model year, and this morning it was in the full up position for the past two days. So, problem is intermittent, and I suspect it is the leaking check valve.

Do you know what the part number is for the rebuild kit?

Thanks.

Don

I'm on my phone and I haven't figured out how to copy and paste a url yet. However, I went to boats.net and the Honda Marine button gets you to a list at the top of which is "outboard parts".

Select 2006 and then your model and finally trim/tilt.

I didn't see a kit listed so Honda doesn’t offer them or boats.net doesn't list them. You might want to check with a Honda parts dealer to see if there are any kits available for your trim unit.

Bit you can see that all of the parts are listed individually. The majority of items needed to repair one of these is properly sized orings and seals. Very few "hard" parts would be required if any. As with any hydraulic valve set up, if no scoring is observed on lands or bores, those parts may be successfully reused.