impeller

[catchingmore]

i have a 74 50 hp i just took it out see if i got a good deal on it and it started and ran fine but i did not see any water coming out the to reclangler holes i think they where exaust but i not sure cause merc is new to me i was wondering what it might be if the impeller is bad or could it be something else and if it is what is involved in replacing it hard or simple i did my rude and it was not that bad any pic would be great i am wating for my manual from ebay and would like to at least get it started so i can be in the water on wed thanks to all

 

[TriadSteeler]

Re: impeller

If you don't know when the last time the impeller was changed or if it was more than two seasons ago. Change it. You may want to change the entire water pump housing.

I have that same motor. The rectangular ports are the idle exhaust ports. What you want to look at is the tell-tale stream that comes out at the seam a couple of inches below the wraparound cowl on the rear starboard quarter of the motor. That should put out a stream of water. (See pic below) Very often this hole is plugged up as insects love to build nests. Run a length of string trimmer wire up there and/or blow some compressed air to clear it out. If you don't get flow out of the tell-tale, then feel the water jacket. If it gets too hot to touch, then your impeller isn't pumping.

Here is an exploded pic of the lower unit and an exploded pic of the water pump (yours is the high pressure model on the left). My advice is to get a manual and change that impeller now. $20.00 and a few hours is really cheap insurance