1986 evinrude tilt pump problem

[tonym]

I have a 1986 40 hp evinrude motor AE40ELCDE with the tilt pump mounted on the right hand side.( it is the original pump.) not many models came out with this pump. There is no problem going up or down but it does not stay up it gradually goes back down with its own weight may take 2 or 3 minuits.Has any one had this problem or can any one suggest what could the problem be I've replaced the valve at the bottom of the pump and honed the cylinder but it made no difference. Ill post a photo of the pump.
thanking you.
Tony

 

[faztbullet]

Could be manual release valve bleeding by or internal check valve. Not many parts for this to service anymore.

 

[tonym]

Thanks for that info I've replaced Manuel release valve made no difference ,would it be hard to open it apart. so I can check that internal check valve or any parts that could be causing it to bleed back I do have a brand new gasket if I split it open. I haven't been able to get much info.on this pump,
Would anybody out there have a diagram of this pump
thanking you Cheers Tony