Evinrude tell tail not discharging

[BillBW]

Ahoy. I have a 1988 Evinrude 100XP that I just purchased. When I start the engine on muffs with my garden hose, the tell tail puts out water (note: I'm careful to not turn the hose on too much, just a quarter turn at the spigot) - there's not a crazy hard pressure stream coming out, but enough to let me know it's working. When I then put the boat in the water and run it, no tell tail discharge..... what gives here?
Note that I ran the boat for about 15 minutes out in the bay and still no discharge so we came back to the ramp, hauled her home and I went back on the muffs to flush the engine, and the tell tail was discharging like before. Why would it not discharge in the bay, but does so on the muffs?
The boat is a beautiful 1988 BW Montauk 17 with original teak. Thanks so much!

 

[Sea Rider]

Welcome to IBoats,

So that's a second hand 33 year oldie motor that wil be used in salt water, assume the previous oner used it in salt water too. When flushing on muffs open the whole spigot, there's water scaping around the ear muffs sides that will lessen the water presuure with which the motor is being flushed.

When flushing poke a plastic cannula, stif wire up/down the peeing indicator several times, probably there's a partial clog going on there ?

Happy Boating​

 

[racerone]

A new purchase needs a new impeller !

 

[tphoyt]

Agreed!
New to you = water pump service and may as well change the gear oil while your at it.