merc 25hp water pump problem

[H2Odog]

First a little background, This is a buddy of mines motor. The water was just trickling out of the hole. So I replaced the impeller and gaskets for him. The old impeller did not look bad at all. <br />I started it up today and same thing just trickling. A couple things I noticed. there is a small hole toward the boat in front of the lower unit oil vent. Water was coming out of there is that correct? also when I put my finger on it to plug it and see what it did water was coming out of where the shift linkage comes out of the lower unit? <br /><br />Before I put the lower unit back on I did make sure that the hose went into the pick up tube and also made sure the hose from the motor was clear.<br /><br />Almost forgot 1998 25hp merc outboard<br /><br />Any suggestions?<br />Thanks

 

[Nos4r2]

Re: merc 25hp water pump problem

Try backflushing the motor through the pee hole with water-it might just have a blockage in the hole.(check with Laddies 1st though if its ok to do on that particular motor)<br /><br />It worked a treat on my old 50 merc-loads of scaly crud came out and the pee stream was a river afterwards.

 

[badbean]

Re: merc 25hp water pump problem

Yeah sometimes in my Merc. sediment or whatever gets caught up in the pee hole nozzle and impedes the water flow. I usually disconnect the discharge hose from the back of the pee hole nozzle and let it flush out that way. A friend of mine tottaly removed his pee hole nozzle and ran a straight wider diameter tube in its place.

 

[H2Odog]

Re: merc 25hp water pump problem

ok so i checked all the hoses for blockage etc. I took out the thermostat and decided to replace that. Before I replaced it though I put the t-stat cover back on without the t-stat to make sure there wasnt a blockage elsewhere. Started it up and water poured out of the hose. Now when I put the t-stat back in it just trickled again. let it run for about a min. same just a trickle. Is this typical of mercury's? I know my johnson kicks out the water.

 

[MercFan]

Re: merc 25hp water pump problem

I'm no expert, but I'd venture to say, take it to open water, run it at full power for a minute or 2. The water coming out of the tell tale should never burn you. Running on muffs at idling probably just doesn't get the thermostat to "open temperature". At temperature the thermostat should open and give you full pee.