Water pump 2.5L Mercury

[RidgeRunner]

Your water pump impeller is toast. The rest is normal stuff. The Merc impeller is small compared to say my 90 Johnrude and even later model Mercs. They work just fine, just smaller. A little up and down play in the driveshaft is also normal although a little alarming to me. The lowers on these outboards are pretty darn crude.

[draglink]

My 2.4 tends to run warm. It will overheat with T-stats in...I've run with out for years. BUT if yours runs normal temp with T-stats then def put them in as Destroyer said

[jasoncooperpcola]

Thanks everybody. Looks like Mercury Parts Express for the water pump and t stats. Do I need to replace the lower housing? And how much driveshaft play is not good? I will mark it when i get home and see how much it is. Its around 1/8" to 1/4".

[Destroyer]

Originally Posted by jasoncooperpcola

Thanks everybody. Looks like Mercury Parts Express for the water pump and t stats. Do I need to replace the lower housing? And how much driveshaft play is not good? I will mark it when i get home and see how much it is. Its around 1/8" to 1/4".

Truthfully I don't know how much play is acceptable. Not much I'm sure. I'll look in my various service manuals when I get home and see if I can find a suitable answer. I'll post it here unless someone else answers first.

[THEFERMANATOR]

Originally Posted by draglink

My 2.4 tends to run warm. It will overheat with T-stats in...I've run with out for years. BUT if yours runs normal temp with T-stats then def put them in as Destroyer said

On some mERCS taking teh t-stats out can burn one up in a hurry. The poppit valve assembly must be working for the cooling system to work, otherwise the stats can't work. And that impeller is done. The impeller vanes need to stick straight out as that is how they work. These pumps are a displacement design where the impeller fins move in and out to compress the water out and pull the water in. Once the impeller vanes get laid over like the ones pictured, it is no longer pumping much. This is most important at high RPM's as the vanes need to move in and out rapidly. And the MERC impellers are a tall but short vaned design as they are a high pressure design meant for MERCRY's poppit controlled cooling system whereas other engine manufacturers used a high volume design with longer impeller vanes that aren't as tall.

[Destroyer]

Originally Posted by RidgeRunner

Your water pump impeller is toast.

Ridge? I'm always willing to learn. Based on the pictures, could you explain to me why you think his impeller is toast? I mean, don't misunderstand me, it's always a good idea to replace the impeller every year, and since he has it apart anyway, now would be a perfect time. But what is it in the pics that makes you think it's toast? Looking at the pics I can see a little normal wear on the leading edge of the vanes, but nothing that looks out of the ordinary to me. I don't see any cuts, tears, cracking or evidence of overheating. Am I looking in the wrong place?

[jasoncooperpcola]

There is cracking very slightly where the vanes curl over. You can see it in the pics, i can get a closer pic too. That may be what he saw. I opened the housing expecting to find bits and pieces of an impeller. The driveshaft has about an 1/8" maybe a little under that of play. Also has side to side play? Is that ok?

Back to bottom paint stripping!

[Destroyer]

Originally Posted by jasoncooperpcola

There is cracking very slightly where the vanes curl over. You can see it in the pics, i can get a closer pic too. That may be what he saw. I opened the housing expecting to find bits and pieces of an impeller. The driveshaft has about an 1/8" maybe a little under that of play. Also has side to side play? Is that ok?

Back to bottom paint stripping!

If there's any cracking then it's toast. Sad to say, looks like it had a lot of life left in it.

[jasoncooperpcola]

I did not know that Ferm. I am buying a new complete water pump. The old one is going in the box for a spare. No wonder it never seemed like it was pumping enough. Now that I look at it, the Merc impeller is tall. I did notice the housing is offset from the driveshaft and wasn't someone on here asking about that? Thanks for the info Destroyer and Ferm. Does Merc Parts offer a complete water pump kit or will I have to pay more for each piece?

[jasoncooperpcola]

Also the thermostats were shot. I took them out about a month ago when i found they were broken. I run the motor on the weekend for ten minutes, so I hope nothing is hurt.