'85 Evinrude Super 45 (Commercial) Water circulation problem

Hello All, I'm new to this forum having recently purchased my first boat. I'm not sure if you can help me but I have a technical question regarding my '85 Evinrude 45 Super, E45RSZ.

Prior to having some recent work done to the water pump, I was experiencing that after running the outboard for 15 or 20 minutes, then shutting it off for a while it was reluctant to restart without re-choking the engine and a few pumps of the primer bulb. So, just before Christmas I took it to a reputable Evinrude mechanic to have the impeller replaced and on his advice he rebuilt the pump.

The mechanic suggested when I collected it that the motor was "running cold" which he thought may have been caused by a missing thermostat. I purchased a new thermostat and gaskets from him and installed it myself even though I discovered that there was a thermostat and it was working correctly. I thanked him, paid the money (which was my grocery money for the fortnight plus some) and over the holidays went to put my boat in the water only to find that no water was flowing out of the telltale. So much for my holiday plans of getting out on the water here in Australia.

Today I took it back to the mechanic who carried out the work. He removed the lower unit and tested the rebuilt pump, which seems to be working fine. He also placed a hose up the water tube to see if water was circulating through the power head without the lower unit in place, which it is.

The problem seems to be that when the lower unit installed no water is reaching the power head. I'm just wondering if anyone might be able to suggest where he (and I) should be looking in order to try and rectify whatever fault is causing this problem as he is at a loss to explain why this is happening and now we are both left scratching our heads. I appreciate that the outboard is old, but it's all I can afford and I don't have alot of money to throw at it.

Any input would be greatly appreciated

Re: '85 Evinrude Super 45 (Commercial) Water circulation problem

My guess would be either the pump is not connected to the water tube when he is re-installing the lower unit , or the key is not installed correctly on the impeller causing it not to spin with the drive shaft.
Also it could have to do with the thermostat maybe it's stuck shut was it pumping water before you messed with the thermostat ? I assume since he said the motor was running "cold" he had the water pump working properly before the thermostat was messed with.

Just my .02

Re: '85 Evinrude Super 45 (Commercial) Water circulation problem

Blake, Thank you for your reply. The Impeller is spinning with the drive shaft and it would seem that the water tube is connected correctly. The lower unit was run separately in the test tank with a drill attachment connected to the prop just to be sure.

As for the Thermostat, well it's been tested and is installed correctly. My mechanic assures me that it was pumping water and was working fine after the water pump rebuild before I brought the boat home. I didn't run it to check for about three days afterwards but when I did run it with the flushing muffs before I replaced the thermostat I didn't have a water stream from the tell tale.

My mechanic suspects that there could be a leak in a water passage in the power head somewhere and is currently in the process of removing the power head for a closer inspection. There doesn't appear to be any water reaching the power head so I'm assuming that a hole somewhere here would result in a 'vacuum' type pressure loss somewhere in the passages thus preventing water from being drawn all the way through the system? I'm also assuming that the water pump does not deliver the same amount of pressure to the passages as the "garden hose up the tube" does? This would explain why there is water coming out the tell tale when a garden hose is applied but not coming through when the lower unit is attached and running?

Re: '85 Evinrude Super 45 (Commercial) Water circulation problem

On my yamaha , the old impeller had broken up while running and small parts of the rubber impeller got stuck in my water passages causing no water to flow threw my block / no tell tail. So I had to pull off my exhaust cover plate and there was rubber all in the water passages I cleaned it all out and got my water pressure back. So maybe you have blockage in your passage ways , I don't think you can have a "leak" in the powerhead water passage ways. But I could be wrong.

And yes you will have more water pressure when directly shooting water up your tube vs the impeller shooting water up on the muffs. And you will also have more water pressure while running with the boat in the water and the impeller/lower unit fully submerged.

Re: '85 Evinrude Super 45 (Commercial) Water circulation problem

Well the problem with the water circulation has been fixed. Thank you Blake for your input.

It turned out as I suspected, the gromet in the bottom of the power head, where the top of the water tube attaches, had self destructed with age. This was causing a blockage that prevented water from entering the power head under normal operation.

I won't comment on my thoughts regarding the job card other than to say that I'm not too pleased with the bill!