1975 johnson 115 power tilt & trim

[buttzy]

Hi I am in need of some help with my tilt & trim. The tilt will go up but not down and the trim wont move at all. it seems like it locks up win i try to go down. Motor works fine it seems to be in the hydrolic. Any help would be great.

Thanks Jon

 

[RRitt]

Re: 1975 johnson 115 power tilt & trim

when system doesn't move does motor keep spinning? problem is probably in the pump but behavior of motor will help to identify which part of pump. the rams don't really care which direction they go. They're just a piston stuck in a tube. As long as you don't mechanically bind them then up is same as down to a ram.

if motor stops spinning when ram stops moving then the pump is trying to deliver pressure but there is nowhere for the back pressure to escape. chances are good that the problem is your shuttle valve inside valve body not going back the other way to release fluid.

if motor keeps spinning when ram stops moving then the pump isn't putting out full PSI on the down direction. could be check valve, could be debris, could be release valve ... could even simply be low on fluid.

 

[buttzy]

Re: 1975 johnson 115 power tilt & trim

The motor still spins and it sounds like it is binding up. i was told by someone else to take the small rams apart to check seals. does this sound write? i think i checked the check valve. is it below the motor with a big flat head screw to access? how do i access these valves?
thanks Jon

 

[gejandsons]

Re: 1975 johnson 115 power tilt & trim

If the small rams as called have bad seals you will see oil leaking around the polished rod. System could be air locked. Find the relief screw or crack the connections on the lines & operate the pump. The reservoir holds only a small amount of oil, so it doesn't take muck of a leak to be too low on fuid to operate.

 

[RRitt]

Re: 1975 johnson 115 power tilt & trim

The motor still spins and it sounds like it is binding up. i was told by someone else to take the small rams apart to check seals. does this sound write? i think i checked the check valve. is it below the motor with a big flat head screw to access? how do i access these valves?
thanks Jon

if the motor becomes noticeably labored then what is probably happening is ....
the motor and cylinders are functioning fine. But the pump is not opening the release valve in down direction. So your cylinders can go up but never down because there is no way for the bottom fluid to escape. If the cylinder was bad then either fluid would come squirting out top or the engine would bleed down rapidly.

do you have a calco or a prestolite?

Assumming prestolite my guess is that you need a new oring on your shuttle valve. Pumps are relatively complicated little devices. It could be any number of things but my odds-on favorite would be shuttle valve oring.