Double check the line routing as I said in my previous post. The high pressure port is the "UP" port on the pump body (left side as you look at the pump). This should be hooked to the end of the cylinder towards the transom and should extend the cylinder. If that is correct, determine what your output pressure is. If it's in the 2000+ psi range, it may be a Bravo pump, which has a tough time getting to 3000psi because it's a faster rate pump (taller rotor) that has more rotor leakage and takes more hp to turn. If it's already a 3000+psi pump (competition style), you really can't push it much higher. And as FloridianSon said, you should find out what the max working pressure your rams are designed for.

Good point, I forgot he's not talking about pushing the tab down, it pushes up, I assume, without the pump running. When the pump is not turning, the locking/shuttle valves hold the pressure, not the standard relief pump pressure valves. Also there is a thermal/overload relief valve on the high pressure side that could leak.

Just a little over-zealous in responding the first time.

Ok I have tried 2 new bravo style pumps and one used HP pump with the same results. Has enough pressure to extend the tab but will not hold in position. The hoses are correct , when I reversed them the tab would not fully extend. I don't want to seem stupid but what are shuttles? I did reseal the cylinders and they looked ok.
Shawn sorry if you feel I hyjacked your thread but you still owe me a boat ride

system

#1 shuttle #4 thermal relief that is on the up side or the tab down.#3#4 pressure relief they make the pressure that the specs call for.

Am I right assuming the 4 is on the high pressure side? So If I increase the pressure on that spring my system will hold more pressure?

walters if you have tryed new pumpes then I would think you need a stronger spring on the thermal but I have never seen one offered.I think the problem is it is a single tab with a lot of pressure on it from the boat.Just my .02

Sorry we need to be in the chat room Yes I think if you increase the spring size it will take more pressure before it would let anything slip by.

After trying more than one pump, I would test/check the rams. What kind of rams are they? For a quick test of the o-rings, you could extend the cylinders completely, remove and cap the low pressure line at the rod end of the cylinder but leave the cylinder port open, then run the pump a bit more. Does more oil come out of the cylinder port? If so, it has to be leaking around the piston.

Ok I think I am understanding now .An increase in spring pressure on 1 and 4 will help my system hold more pressure. Is that correct?.
Thank you very much for all the help. I have been working with this problem for 2 years with no sucess.