how do I check if my water pump is working??

[gmanh4u]

I have a 1970's merc 800 that I recently purchased and I do not know much about outboards and before I drop it in the water I want to make sure everything is OK. I connected the "earmuffs" to the lower unit and started it up, but I am not sure where the water should come out or how much should be coming out. The engine starts and runs good. Can someone help me out?

 

[tmcalavy]

Re: how do I check if my water pump is working??

Take the top and cowl/cover off. Look for a rubber hose that exits through the back of the bottom cover. On my 73 Merc 500 it is on the port side. After you find it, check the tube for mud dauber nest remnants...they love to build nests in little holes. You can use a soft wire or compressed air to blow the line clean. If your pump is working, your motor will pee out the hole...gaining strength/stream as you boost the rpms slightly. Don't go WOT though...bad thing on the muffs. Another way to tell is if you can touch the water jackets (sides of the cylinder block) and keep your hand/finger there without it getting so hot you remove your hand. That means water is circulating and cooling. If you have any doubt, however, it is always good maintenance to rebuild the pump and replace the impeller every other year. Since this is a new motor to you, its good for your peace of mind to do this anyway.

 

[gmanh4u]

Re: how do I check if my water pump is working??

thank you for the advise. I may just go ahead and pull it apart and clean/rebuild it anyway. where is the best place to get the parts? I am sure that I can handle the repair, I work on cars everyday. I do plan on picking up a manual. Also the guy I baught it from said he never had any problems with it but he had not used it in almost two years. and as to getting hot to the touch, It does seem to get hot.

 

[tmcalavy]

Re: how do I check if my water pump is working??

Oops, the tattle tale hole on my Merc is on the STARBOARD side, not port side. Its been a long day. If it gets too hot to keep you hand on it, time to drop the LU and rebuild the pump and replace the impeller. Iboats store should have the parts/impeller. Last time I did mine was about $50 or less for the whole shebang. If you don't have a manual, the Seloc brand is good...lots of photos and good instructions.

 

[lonny bitton]

i have a 1970 100hp johnson the boat shop put a new water pump in the motor blew out the lines and we had blown a right side head gasket they put a new one in and it is running band they have taken off the thermostats out blew out the lines and the side that blew the head gasket is runing cooler than the head side that did not blow. new pump still no water pumping they are baffles as they work every day on older motors and my boat mechanic is scratching his head maybe you can give me some answers at my e-mail address lonnybit@gmail.com