Yamaha tilt problem

phukbp · 04-26-2012, 01:56 PM

I have a 2001 F115 Yamaha that had leaking seals and water intrusion on the tilt and trim assembly. The unit worked ok but leaked pretty bad. I took all three rams out and replaced all the ram o-rings, scrapers, and dust seals. While I was doing the work I also took the whole assembly off and drained all the old fluid out and flushed with new hydraulic fluid. Reassembled everything and bled it numerous times. It worked fine in both directions until I went to get off the trailer at the marina. When the motor is in reverse and given throttle it jumps up and falls back down

So, I tried bleeding again and again and have had no luck. The tilt holds in the up position and works fine while under way. The only problem is that you can manually pull it up while it is in the down position. I am starting to think I have a bad manual bypass valve assembly. I have already spent a hundred bucks in seals so I would like to get some advice before I throw more money at this thing. If anyone has any ideas on how to troubleshoot or experience with this type of problem I would appreciate your input.
Thanks.
Brad

outbrdwrench · 04-26-2012, 03:10 PM

Did it act this way before you took it apart? If not then you must have got something wrong when you reassemled. If the motor holds when you push down on it, but not when you pull up,then the bypass valve is not the issue. Or maybe I should say it is very very unlikley.

Sequoiha · 04-26-2012, 07:02 PM

It sounds like you are having an issue with the free piston, this is underneath the tilt sub assembly, which is the center ram. when you pull the ram out it causes a suction on the free piston and dislodges it. if it is even tilted or cocked slightly it will cause this issue, the purpose of the free piston is a shock absorber for impact so it does not fall back down hard enough to blow the sub assembly out the bottom . hope this helps.

TheCaptKen · 04-26-2012, 09:18 PM

I figured that when you removed the valve assembly off the end of the center piston, you didn't get something together correctly

phukbp · 04-27-2012, 02:07 PM

It did not do this before I took it apart. It just leaked real bad. I put the valve assembly, the thing on the bottom of the center ram, back together like I took it apart. Is this the piece ya'll are talking about that could be causing my problem? It has the four springs, seal, and the nut that holds it all together. When I re-assembled I just good-and-tighted it. I am sure it has a torque spec but I could not find it at the time. Anyone know what the torque is supposed to be?

04-26-2012, 01:56 PM	#1
phukbp Junior Member Ruby Red Lip Join Date: Jun 2010 Location: Pcola Posts: 29	Yamaha tilt problem I have a 2001 F115 Yamaha that had leaking seals and water intrusion on the tilt and trim assembly. The unit worked ok but leaked pretty bad. I took all three rams out and replaced all the ram o-rings, scrapers, and dust seals. While I was doing the work I also took the whole assembly off and drained all the old fluid out and flushed with new hydraulic fluid. Reassembled everything and bled it numerous times. It worked fine in both directions until I went to get off the trailer at the marina. When the motor is in reverse and given throttle it jumps up and falls back down So, I tried bleeding again and again and have had no luck. The tilt holds in the up position and works fine while under way. The only problem is that you can manually pull it up while it is in the down position. I am starting to think I have a bad manual bypass valve assembly. I have already spent a hundred bucks in seals so I would like to get some advice before I throw more money at this thing. If anyone has any ideas on how to troubleshoot or experience with this type of problem I would appreciate your input. Thanks. Brad

04-26-2012, 03:10 PM	#2
outbrdwrench Senior Member Mingo Join Date: Apr 2009 Location: Pace, Florida Posts: 149	Did it act this way before you took it apart? If not then you must have got something wrong when you reassemled. If the motor holds when you push down on it, but not when you pull up,then the bypass valve is not the issue. Or maybe I should say it is very very unlikley. Last edited by outbrdwrench; 04-26-2012 at 06:14 PM.

04-26-2012, 07:02 PM	#3
Sequoiha Senior Member White Marlin Join Date: Sep 2007 Location: Orange Beach Al. Posts: 2,967	It sounds like you are having an issue with the free piston, this is underneath the tilt sub assembly, which is the center ram. when you pull the ram out it causes a suction on the free piston and dislodges it. if it is even tilted or cocked slightly it will cause this issue, the purpose of the free piston is a shock absorber for impact so it does not fall back down hard enough to blow the sub assembly out the bottom . hope this helps. __________________ Kenny Mann Ms Penny Fishing Team Member NRA 172499461 Barber Marina 1-251-987-2628 (BOAT) www.barbermarina.com Sequoiha@mediacombb.net

04-26-2012, 09:18 PM	#4
TheCaptKen Senior Member Snapper Join Date: Mar 2011 Posts: 510	I figured that when you removed the valve assembly off the end of the center piston, you didn't get something together correctly __________________ NelsonMarineService.com Located on the Sunny Beaches of Panama City Beach

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04-27-2012, 02:07 PM	#5
phukbp Junior Member Ruby Red Lip Join Date: Jun 2010 Location: Pcola Posts: 29	It did not do this before I took it apart. It just leaked real bad. I put the valve assembly, the thing on the bottom of the center ram, back together like I took it apart. Is this the piece ya'll are talking about that could be causing my problem? It has the four springs, seal, and the nut that holds it all together. When I re-assembled I just good-and-tighted it. I am sure it has a torque spec but I could not find it at the time. Anyone know what the torque is supposed to be?

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