Yamaha Hydraulic circuit

[chismac]

Can any one help with a hydraulic circuit diamgram for a '87 140HP tilt trim hydraulic system<br /><br />Many thanks

 

[corm]

Re: Yamaha Hydraulic circuit

Hi Chismac<br />Is it a single ram sys or a dual trim and a single tilt ram sys? It really needs a pressure test to see where the leak down is happening at. Also does it have hoses comming out of the pump or are the oil passages internal.<br />If you can't tell, I've not worked on one. They only make a few different styles and are verry close it design,so I'll try and help.<br />...have fun...corm

 

[chismac]

Re: Yamaha Hydraulic circuit

Hi Corm<br /><br />Thanks for the reply. The system is a twin trim ram, single tilt ram with all the plumbing internal except for the "pig tail" lines running to the rams.<br /><br />I am now in the process of mapping the circuit to identify where all the check and control valves are so that I can diagnose the circuit. <br /><br />Thanks<br /><br />Chismac

 

[chismac]

Re: Yamaha Hydraulic circuit

Hi Corm<br /><br />I have found the problem. After stripping the unit right down and spending 2 hours mapping the circuit, by logic, the problem came down to a leaking check valve. There are 3 check valves, one for up and two to give the balance between tilt and trim for down. The up check valve is located in the reservoir (not where I would have looked for it) and close inspection found it had some debris stuck in it. Easy to fix but hard to find.<br /><br />Chismac

 

[cajun150]

Re: Yamaha Hydraulic circuit

Hi Chismac<br />This sounds like the same problem I am having with the trim on my '91 Yamaha 90hp. Maybe the fix you made on your trim will work on mine. Where exactly in the system resevoir is this check valve? Will I need to have a manual with a diagram for disassembly or are the internal parts relatively simple. Thanks.<br />cajun150

 

[flemmer]

Re: Yamaha Hydraulic circuit

i got the compleat trim manual scaned in , drop me a line and i will e mail to you