Trim pump and bypass pressure Help needed
 

I have a large tunnel tab on my motion cat. 43''x26'' The problem is that in rough water the tab works its way back up. I have the standard plastic reservoir pump. My question is where is the by pass valve in this pump and is there any adjustment to increase the pressure it takes to allow the cylinders to over come the bypass ?. I have tried two new pumps with the same results.

Re: Trim pump and bypass pressure
 

ttt

Re: Trim pump and bypass pressure
 

Could it be the trim cyl. with and internal leak or the shock piston?

Re: Trim pump and bypass pressure
 

It shouldn't be the up or dn relief valves if you can trim it under load. They are isolated from the circuit when the pump isn't running. There is also a thermal relief valve on the high pressure side (labeled up) that is set very to 4500psi or higher so I doubt if it's a pressure related issue on that. Make sure that the line that pushes down the tab is connected to the "up" port on the pump (left hand side when facing the ports). The reason it's labeled up is that the pump was originally designed for drives and higher pressure is used on the up side for a drive while a tab needs higher pressure on the down side. I hope this helps you diagnose your problem.

Re: Trim pump and bypass pressure
 

The hoses are hooked to the correct side of the pump. Maybe the cylinders have an internal leak even though they are new. The rams have no provision for shock relief. Thanks for the imput. Any other ideas?

Re: Trim pump and bypass pressure
 

sounds like cyl internal leak. i am having the same problem with the port drive on the AGITATOR and i put a new trim pump on it and it still wont stay trimed out. i am changing rams tonight i will let you know if it fixes it seeya charlie

Re: Trim pump and bypass pressure
 

sounds like cyl internal leak. i am having the same problem with the port drive on the AGITATOR and i put a new trim pump on it and it still wont stay trimed out. i am changing rams tonight i will let you know if it fixes it seeya charlie :drink:

Re: Trim pump and bypass pressure
 

You still could have a pump problem, but I was just saying that I don't think it's related to what pressure setting that the pump is at if you can trim the tab down while you are running. Sometimes the shuttle or thermal relief can keep it from holding pressure.

Re: Trim pump and bypass pressure
 

you still my have apump problem .If the pump is a stock k plane pump the high side psi is 1800psi. the lo is 800psi. I have had planes that need the comp.pump which is 2600psi. high side and low is 1800psi. just a thought CMS Racing P4-5

Re: Trim pump and bypass pressure
 

I have same droopy/sag on my port Bravo1. Did changing the rams solve yours?