New circulating pump last spring, raw water impeller 2 weeks ago, new thermostat, and engine overheats. Ran the hose in and out and back and forth and water seems to be flowing unrestricted. Can anyone suggest next steps?
I've used a garden hose to run water through all of the hoses and exhaust manifold and it seems that the flow is equal to the input. I isolated the water input today by feeding water directly to the raw water pump, bypassing the intake from the foot. ( a local marine mechanic suggested that I may have a kink / blockage in the water input system ) The end result was the same. At 1500 RPM, the engine climbs past 160 heading into the 180 range with no sign of decrease. Am I looking at a blockabe in the exhaust manifold / riser ?
Hook up a hose from the inlet side of the pump, and put it in a bucket of water and see if it will pick up the water. This will isolate the drive in case there are any air leaks in it.
Might want to look at that impeller again. After this many times of not pumping, it could be bad again. It could also be a defective pump cover seal or shaft seal sucking air.
You didn't mix up the in and out hoses on the pump did you?
I changed the seals a couple of weeks back when I started having the problem. The hoses aren't mixed ( if this was the case I would suspect that I wouldn't have any water flowing through the engine. I runs great without the thermostat but I know this is a no...no for the engine. I'm not looking forward to removing the riser or exhaust manifold if it comes to that. How many cases have you heard where the riser or manifold is blocked from rust etc.
I've got a copy and have been refering to it as well. I just got finished isolating the raw water pump altogether. I disconnected the feed hose ( lower hose ) from the raw pump assy. I connected a arden hose to the lower hose and ran the engine with the same result. The temp rises straight through 160 on it's way to 180-190-200 etc. ( I removed the raw water pump from the engine before doing this test before doing this test.)
I then removed the same hose from the thermostat to the manifold and then I ran water from the garden hose thru that fitting and noticed that there was a pressure build up in the manifold when I removed the hose from the fitting. Is this normal ?
