25hp mercury repair ?

[ready2fish]

My mercury 25hp motor has a small oil leak around the prop shaft and being I'm able to do the work myself so i called a local merc dealer for what parts i might need and told him while i was in there i would replace the water pump impeller, well he said if ain't broke don't mess with it, also he said there was a special tool needed to replace the shaft seal and i would be better off to have them do it.

Is their any one here with knowledge on this motor that can give me advice

[painterfish]

ready2fish this guy helps a lot of people with advise
The Marine Doctor - Index

[ready2fish]

big thanks

[CJseven]

Sent you a PM also sounds as if your dealer doesn't care much for the DIY people. I would change the pump impeller for sure if it hasn't been changed in a year or so, cheap insurance. We are lucky we have two great boat mechanics here the one me and my buddies us most often will give you any type of info you need and would more than likely loan the special tools if I asked. So we usually buy all or parts and supplies from him even if we have to pa a little more than if we ordered off the net just because of his friendly service.

[dipsydiver]

Hope your shaft isn't worn like mine on my 10 h.p. was.A new seal didn't help me.My Merc was a 1988 which I had a lot of hours on it.

[Scrapper]

First off get yourself a manual for that motor...not a seloc or haynes...get the merc manual. This is the ONE and ONLY way to work on them. The cheaper manuals go over a LARGE range of engines...and will leave out things due to the amount information in the book. The merc one will not be cheap...but will show you YOUR engine...and will be MUCH more helpful.

Your tech doesn't sound like he likes dyi. I agree with the previous poster on that...you'll see that alot. You will not have any trouble with it. There are tools you need..most can be borrowed or made out of something else. Although the right ones make it much easier. You need a lower unit seal kit, and water pump kit. As the tech said do the pump also. Get the entire kit if you do not know if it has been done...not just the impellor. Will do a better job and last longer. That way you know what you have.

Your tech also needs to think about what he tells people..."if its not broke don't fix"?? what the heck? If oil comes out...which is rarer than H20 getting in...mainly because water can get in and you won't see oil coming out...due to the oil being naturally thicker. That being said...are almost guarenteed milky colored LU oil. BAD in winter time...as the water separates from the oil it can freeze in the winter and crack case...I would make sure if you have oil leaking from prop shaft you drain the oil soon until you get it fixed as there is probably water in it. I would also make FOR SURE it is LU lube and not possibly residue...I have seen rich oil mixtures and oil floats failing in carbs and leaking down through the engine to the exhaust cause what "looks" like leaking prop shaft and not be...just a thought.

The main thing you need to do is a pressure and vacuum test of the LU. Did the tech mention that? Most manuals I've read and mechs I've talked to say they need to hold 15psi and pull 15" vacuum without failure...many will make them hold 15psi for 30min..if they hold they are good. Most shops can do this for you.

I would also check out the merc forum at iboats.com Great folks there and they LOVE to helpe out. Just some thoughts...good luck!

[ready2fish]

some more very good info thanks