65Hp 1973 Johnson Power Tilt MANUAL LETDOWN VALVE

[Aussie Rob]

Hi..

Im looking for a MANUAL LETDOWN VALVE for a power tilt on my 1973 Johnson 65Hp.

the part no is 0172601 but everywhere I look it says obsolete..

Mine simply wont budge and the screw head simply crumbles (chews out) when i try to undo it.

Is this something stupid like a left hand thread? or is it frozen and I should look at disassemble and work it from the inside If I can reach it??

Anyone familiar with these.. also the piston keeps dropping so im guessing a new set of O rings is needed I know 1 is 1-1/2 OD and the other is 1-3/8 OD but what is the diameter meant to be.???

Thanks in advance

Rob,.

 

[boobie]

Re: 65Hp 1973 Johnson Power Tilt MANUAL LETDOWN VALVE

Go to the Top Secret files at the top of the of this forum and look for salvage yards. You may find something there.

 

[will62]

Re: 65Hp 1973 Johnson Power Tilt MANUAL LETDOWN VALVE

Look closely inside the opening. There should be a c-clip in there that prevents the valve from being backed out more than a couple of turns. If the valve is all the way in, you should have a little more than a 1/16" of clearance from the top of the valve to the back of the clip. If the unit has been painted a couple of times over the years, that gap may be filled with paint. If that's not the case, do you have access to an impact driver? I'd wait to order your o-rings. Your leak-down problem may be caused by this valve.

 

[Aussie Rob]

Re: 65Hp 1973 Johnson Power Tilt MANUAL LETDOWN VALVE

I ended up pulling pump assembly apart leaving the let down screw alone for now.

anyway long story short giving it a clean flush seems to have fixed the problems. leg stable..

very fiddly - just watch the balls, washers and springs they go everywhere.

 

[RRitt]

Re: 65Hp 1973 Johnson Power Tilt MANUAL LETDOWN VALVE

I ended up pulling pump assembly apart leaving the let down screw alone for now.

anyway long story short giving it a clean flush seems to have fixed the problems. leg stable..

very fiddly - just watch the balls, washers and springs they go everywhere.

Bleed down is usually caused by check valves. In my experience, your problem will be back. I would suspect a rust spot on the check valve ball. 1973 should have stamped and formed check valves with a brass seat. they last much longer than 1981-1995 versions but are not repairable. When they go bad then you have to either replace the valve body or find some late model check valves with same diamater. 1973 often used a 1/2" bore. 1/2" CV are almost impossible to find. If so, then just buy a Chrysler/Force VB and plug up the unused ports.