johnma
Guru
You have a manifold on the forward bulkhead located in the compartment below the lower station. Shut off the lever on the inlet to the manifold. if the cycling stops the problem is a leak downstream of the manifold. If the cycling does not stop its the pump or the accumulator.
As far as your impeller is concerned, I have a single Yanmar 370 on my 2003 Mainship 390. If that is your engine its best to remove the pump and change the impeller on your workbench. You will need a ratchet wrench (as opposed to a socket wrench) to remove the pump. I'm not on the boat right now so i'm not sure of the size (12 mm comes to mind).
For oil changes, My 390 came with an oil exchange system and I expect your does also.
If it does, oil changes are simple. Your oil exchanger has a 3 position lever and a toggle switch. One position does your engine and one does your generator. If you have twins, the third position doe your second engine. If you have a Yanmar the horizontally mounted filter can be messy. Shut the engine down and wait a while for the filter to drain. Drill a small hole in the top rear of the filter to facilitate draining, then slide a trash bag as best you can between the filter and the top of the engine. If you have Cummins or Cat, I can't help.
Good luck
John
As far as your impeller is concerned, I have a single Yanmar 370 on my 2003 Mainship 390. If that is your engine its best to remove the pump and change the impeller on your workbench. You will need a ratchet wrench (as opposed to a socket wrench) to remove the pump. I'm not on the boat right now so i'm not sure of the size (12 mm comes to mind).
For oil changes, My 390 came with an oil exchange system and I expect your does also.
If it does, oil changes are simple. Your oil exchanger has a 3 position lever and a toggle switch. One position does your engine and one does your generator. If you have twins, the third position doe your second engine. If you have a Yanmar the horizontally mounted filter can be messy. Shut the engine down and wait a while for the filter to drain. Drill a small hole in the top rear of the filter to facilitate draining, then slide a trash bag as best you can between the filter and the top of the engine. If you have Cummins or Cat, I can't help.
Good luck
John