Yam F60 PTT Sticking

donald463 · 16 July 2012, 17:32

PTT is sluggish to the point of stopping.
Removed piston from engine and it appears to be 'sticking' in cylinder and moves in and out in short jerky movements

with a bit of assistance.
No sign of oil leak but not sure what oil and where to top up.
Have released pressure using screw provided but has no affect and does not release piston.
What do I check next? Has anyone got an exploded view which might help?
Lots of screws but do not want to fiddle without knowing what is what.

9D280 · 16 July 2012, 23:33

On app so apologies for the "text" reply...

You say released pressure- do you mean the bypass screw on the side or the filler on the back?

If i had found that i'd be topping up the reservoir, wind it down and back up, leave for 5-10 mins & repeat until you can't get box more in.

You might be surprised how much oil you can loose with no trace on a pt system... Not that i speak from experience...

spartacus · 17 July 2012, 00:23

If you've used quick release screw on the power trim, then you'll need to purge any air in the system. I've read that the Yammie units use their own power/trim fluid, or Dexron II compatible ATF fluid. Top up the reservoir with fluid. With manual valve open - lift and lower the outboard leg by hand at least 5 times. Recheck fluid level. Only then close the valve and operate power trim. You might have to do this a few times to get it operating properly. Check for leaks - it shouldn't lose fluid.

jyasaki · 17 July 2012, 06:05

PTT is a hydraulic system; Dextron is fine, as is just about any other hydraulic oil. O-rings (or hydraulic seals) won't cause much friction when all elese is considered; I'd be looking elsewhere (motor, pump, switches, etc.)

jky

donald463 · 17 July 2012, 07:42

Quote:

Originally Posted by 9D280

On app so apologies for the "text" reply...

You say released pressure- do you mean the bypass screw on the side or the filler on the back?

If i had found that i'd be topping up the reservoir, wind it down and back up, leave for 5-10 mins & repeat until you can't get box more in.

You might be surprised how much oil you can loose with no trace on a pt system... Not that i speak from experience...

Yes released screw on side but made no difference either powering in or out.
What oil is used?

donald463 · 17 July 2012, 07:45

Quote:

Originally Posted by spartacus

If you've used quick release screw on the power trim, then you'll need to purge any air in the system. I've read that the Yammie units use their own power/trim fluid, or Dexron II compatible ATF fluid. Top up the reservoir with fluid. With manual valve open - lift and lower the outboard leg by hand at least 5 times. Recheck fluid level. Only then close the valve and operate power trim. You might have to do this a few times to get it operating properly. Check for leaks - it shouldn't lose fluid.

Feels like pressure is 'stuck' inside but releasing screw doesn't release pressure and piston cannot be manually pulled/pushed in or out.
Is there another release screw?

Jizm · 17 July 2012, 08:48

If you go to

Www.yamaha-motor.com

You can read through the owners manual, that may help.

9D280 · 17 July 2012, 09:33

Quote:

Originally Posted by donald463

Yes released screw on side but made no difference either powering in or out.

That screw should allow you to raise & lower the engine manually. Either you haven't released it enough, or, it is too slack for it to power itself up & down and all you are doing is pumping fluid round in circles.

Most of those release valves have 3 O-rings behind them - the inner two seal the up / down parts of the plumbing, and when released they unseat and effectively "short circuit" the pump. The outer ring just keeps the fluid inside the casting. If you have opened it, it will be a bit lethargic "on the buttons" as half the fluid moved by the pump will be going round in circles instead of pushing / pulling the piston. Try tightening it & see if it improves matters.

Quote:

Originally Posted by donald463

What oil is used?

Standard automatic transmission fluid. You probably don't need the super high quality stuff, as it's bnot being thrown around to the extent it would be in an auto 'box, so the air rejection properties only become an issue when you fill it from dry and air is purged form awkward corners on the initial up / down. Mine is full of Halford's "own brand standard" fluid.

spartacus · 17 July 2012, 13:53

Quote:

Originally Posted by donald463

Feels like pressure is 'stuck' inside but releasing screw doesn't release pressure and piston cannot be manually pulled/pushed in or out.
Is there another release screw?

With the motor separated from the hydraulic PTT unit - how does it look? Does it work properly, no intermittent bursts of power, knocking sounds, etc? The carbon brushes within the motor are subject to wear - however this would be evident as you'd see bursts of power or the motor turning slowly.

Main thing to do is top up the system first with ATF fluid (assuming it needs topped up), purge the air, then let us know the outcome. My Tohatsu engine took ages to purge after I opened the manual release valve.

Quote:

Originally Posted by 9D280

Mine is full of Halford's "own brand standard" fluid.

Nowt wrong with that. I topped mine up with Mobil ATF220.

donald463 · 17 July 2012, 17:16

Many thanks for all replies.
removed unit complete. Motor running OK in both directions.
Fluid looked like soapy water all frothy so drained all out and refilled with new Dextron 2.
After a bit of purging all now OK and working well.
Found quick release screw needs to very tight otherwise motor works hard and piston goes slow.

spartacus · 17 July 2012, 23:03

Glad you got it sorted.