1979 Evinrude 15HP Water Pump questions

[PAH]

I replaced my entire water pump, housing and all last fall using this kit - https://www.marineengine.com/newparts/part_details.php?pnum=OMC0394711. The new housing used 4 bolts that were all the same length, while the old housing had two long and two short bolts. It worked fine the first couple outings, but then it started to just dribble out the telltale.

1) I pulled the lower unit today. The engine shaft is divided into three columns: exhaust, drive shaft + water tube, and shift linkage. The shift linkage column was full of water which I did not expect. I hooked up a garden hose clamshell attachment to the water intake with low pressure to see if I could identify a leak, and discovered there is a designed in hole on the side of the water pump housing - water flows from the impeller up to the bottom side of the shaft seal and then out the side of the housing and into the shift linkage column. Is that normal, or is this housing not the right one for a 1979? I unfortunately, no longer have the old housing to I see if that had the same feature or not.

2) I attacked a tube to the telltale to try blowing through the water channels to see if it is clogged up. There was some airflow, but also quite a bit of resistance. Should there be much resistance, or should if blow through quite easily?

Thanks in advance,
Pete

 

[racerone]

What did the old impeller look like ?----Correct , the water pump kit is the same part # from 1974 to 2005 I think.

 

[PAH]

The old impeller was fully intact as is the new one, so no rubber chunks stuck in the water channels.

I talked to a local repair guy, who was very helpful. It is normal for the pump to pump water into the shift linkage area, but it is supposed to drain out. Sure enough, the small drain hole was clogged with mineral deposits and muck. Got that cleared out and draining properly.

He also told me it should be easy to blow through the water channels with the lower unit removed, and since I had a dribble from the telltale and water coming out the exhaust ports, it is most likely a partially clogged telltale. So, tomorrow, I'll remove the telltale hose and try to find and clean out the blockage.