dukenrock

I hooked up in the driveway tonight to check everything out and when I hooked to the starboard side everything looked good. Water flowed out the transom exhaust fine. I hooked up to the port side and no water came out the exhaust. I had the low water pick up blocked off and used the side ports. I let the engine run for about 30 seconds a couple of times and was never able to get water flowing.

525's, XR

tcelano

If the block and manifolds are empty, it could easily take that long to fill from the hose. If your impeller isn't in such good shape, the water could have leaked back out the drive on the trailer. Assuming access isn't too bad, pulling the back off the seawater pump to check the impeller is an easy job, just have a rebuild kit (gaskets, impeller and maybe wear plate) on hand before you start. Look for indications that you are getting water into the system (strainers, feel hose pressure at various places on the motor, etc). I'd give it longer than 30 seconds before I got really worried. It would take quite a while at idle to heat anything up to the point of damaging.

The other remote possibilities include clogged strainers, or a blockage upstream the strainer (highly unlikely). If you really think its plugged, and it's not the strainer, troubleshoot the system step by step by disconnecting hoses, and seeing where you can get water to flow to. I still put my money on the first paragraph though.

dukenrock

Motors are closed system. Would it still take that long. The starboard had water within 20 seconds or so.

John B

I had an improperly made CMI which had marginal flow on one side.

It finally overheated the head and block on that side after 6 years and 200 hours.

CMI replaced it at no cost after we sent it back to them for evaluation.

Some Merc motors have a spring loaded contraption in the water splitter to balance the flow to the headers, which could be sticking or malfunctioning.

Also you may have a temporary obstruction on the one side.

dukenrock

Should have trusted my instincts. Motor ran hot immediately so I had to shut her down the minute I launched. I was able to get a hold of Red Dog who helped me diagnose the problem. Bad impeller. He gave me Dynos number and I was able to get a hold of Dyno who immediately located one for me that evening. Fortunately I was able to locate a brand new one at the Grand Haven Yacht Club's marina. I installed the part on Sunday and was able to run later that day. Once again the forum has proved to be an incredible tool an dinvaluable as far as the people on it. Thanks Red Dog and Dyno for helping out.