mmwalters

They are Cylinders from Dana marine and my tab is big 42''x26''

Falcon

I should add, make sure you run the pump in the proper direction. If you don't and you don't have strong cap on the removed line, you will get an oil bath!

mcollinstn

mmwalters,

Check valve on the "up" side,
overpressure valve (#4),
or ram seals.

One of those will be letting your tab creep up.

The outboard/Bravo style pumps have an overpressure relief to allow the motor to kick up if you decide to drive it up the boat ramp at 30 or so.

FloridianSon

Just # 4

mmwalters

Ok Thanks guys I will try that. How come we are all still awake?

Falcon

The thermal pressure setting on the pumps that I have worked are all set at or above 4500psi. This should be high enough. If not, you could damage the pump going much higher. I believe the pump body can crack around the shuttle valve area at about 5500psi. If you have adjustable positions on the tab for the cylinder, as I have seen on Dana tabs, you could move the rod end out further on the tab to change the leverage point. Just pointing out ideas! Good luck!

FloridianSon

If you look at the shuttle it would not matter if it was one hunderd pound on one mill gram spring the door is shut and no pressurs could open it.

FloridianSon

Falcon your right it could.I know one thing that's one big tab and it will put a lot of pressurs on any system.

Falcon

Just saw the tab picture. Those cylinders don't have much leverage on that tab and it doesn't look like moving the rod end out to a further hole is an answer, unless you have new longer piston rods made. What you really need is more piston diameter, but that doesn't look easy either because you don't have much room in the cylinder mounting location.
What I would do is determine the usable range of the tab. How high is high enough and what's the lowest you would like it. Then with the usable stroke range of the current cylinder body determine a good mounting point for a longer piston rod that will still raise the tab high enough. This will maximize your cylinder leverage on the tab with the current cylinder design. Of course, I wouldn't do this until it's determined that you don't have an internal cylinder leak as the real culprit.

Time to get some sleep!

FloridianSon

Falcon I am thinking like you if he moves the point out further it should lessen the pressure.If he does not ever use the tab in the full down pisition there should be ram to meet his needs.