Outboard Motor Question - PeachParts Mercedes-Benz Forum

tobybul · #1 10-05-2009, 10:20 PM

Anybody good with outboard motors? I just got a used 1997 25 hp Merc which appears to be in very good shape. Starts at first pull. I haven't put it in the water yet but I put muffs when I test it. I don't run it for very long (about 1-2 minutes) because I notice that water does not come out of the water exit.

It sort of spits a bit at first but then stops. I don't know if I should run it longer since maybe the tsat has not opened yet. or put the water intake in s tub of water instead of using muffs.

Any thoughts???

R Leo · #2 10-05-2009, 10:29 PM

The little pisser stream is right off the waterpump output. It indicates that the waterpump in the lower unit is functioning. Sometimes, a bug makes a nest or some crap gets caught in the pisser nozzle. Take a piece of wire and poke it in there to clean it out.

If no water comes out even then, you probably have a problem with the waterpump impeller...not a big deal to fix if you're mechanically savvy.

Find a Clymer manual for that motor and review the procedure before digging into it.

Good luck.

compress ignite · #3 10-05-2009, 10:41 PM

If it's been used in the "lake",RLEO has your answer.

If however,It's been used in SALT or Brackish water I'd consider running it
with some "Salt Away":http://www.saltawayproducts.com/ApplicationsPage.htm
or other saline removal system.
Once you take the cowling off the outboard's Head and GENTLY take the rubber hose off the "Telltale" nipple from the
inside ...you'll be able to see what it's prior environment was.
Lotta Corrosion = Salt.

These babies have rubber water pump impellers and replacing one every two years would not be excessive,in Salt Water use.
The thing is it's as much trouble to "Look And See" about the condition of the Impeller as to replace it.
Generally the Impeller will be on the Vertical Driveshaft (from the PowerHead to the Foot)
When I take the "Foot" off of an outdrive(If it has an internal WP) or outboard
I'll have a WP kit at hand to replace the WP Impeller,Gaskets,Etc.
It's also a good idea to compare the condition of the old "Zincs" (Internal)
to new ones ,so you can see how "Used Up" they are.'Replace if 1/3 gone.

The attached picture is from a used outboard dealer trying to sell one just like yours.
The WP "Telltale" is shown directly under the letter "a" in Water pump on
the imposed claim of the WP (They mean "Impeller") "Being Strong."
Here's the link with all the pictures:
http://www.smalloutboards.com/m25.htm

Oh, and here's a forum for your M 25Hp:http://forums.iboats.com/showthread.php?t=304045
'With one of particular interest to you:
http://forums.iboats.com/showthread.php?t=267085

Clymer:http://www.clymer.com/Book.aspx?bid=639&title=Mercury%2FMariner+2.5+-+60+HP+Two-Stroke+Outboards+%28Includes+Jet+Drive+Models%29%2C+1994-1997
[Hoo! I'd look around the web for a better price.]

whunter · #4 10-06-2009, 04:57 PM

to General Information.

kerry · #5 10-06-2009, 06:01 PM

I run mine in a 55 gallon plastic drum to test them.

Hatterasguy · #6 10-06-2009, 06:39 PM

The impeller could be bad.

First pull the T stat out and flush some water through the system. They can get silted up.

Chris W. · #7 10-06-2009, 06:49 PM

Did I miss something? If you don't have the motor in a tub of water, or don't have one of those hose attachments hooked up to feed it water, it's not going to spit water out because it's not sucking any in!

Rgds,
Chris W.

Hatterasguy · #8 10-06-2009, 06:50 PM

He said he had the muff's on it.

Chris W. · #9 10-06-2009, 07:07 PM

Silly me.... I thought he meant ear muffs to protect his ears from the unmuffled exhaust noise!

Rgds,
Chris W.

markho · #10 10-06-2009, 08:01 PM

look, easy list of things to do.

1 Buy shop manual

2 Change gear oil (little nut at bottom of the lower unit)

3 Change spark w/antiseize

4 Change Fuel Filter

5 Change Impeller and seals

7 Run a can of SeaFoam and decarb the cylinders and throttle body. Spray seafoam into the carb and smoke out the neighbors, then spray a bunch in the cylinder/s. let them sit for 30 minutes and start her up. Breaks free the varnish and your cold starts in the winter will be sharp.

8 Remove Carb and either hand clean, or preferably dip at the shop (Make sure the float is not cracked-my 2001 40hp Merc broke on the water after catching a 9 pound tog in the bay, made the local fisherman rag! (below)

Do all this even if you feel it runs "great".

There aren't any roads on the water. Saftey First!!! DOn't ask How I knows!!

PS- Make sure you drain the gearcase before winter if your in the colder climates. Milky oil indicates water intrusion.

tobybul · #11 10-06-2009, 10:20 PM

No sweat Fellas. I dropped the lower unit tonight and opened up the pump housing to check the impeller. Everything looked good. Also removed tsat and dropped it in boiling water and it opened. Blew compressed air thru water tube and felt it exit the tsat housing. Cleaned up lower unit and will reassemble tomorrow.

Didn't see anything unusual.

Maybe am not waiting long enough for the engine to warm up but I believe there is a bypass on the tsat that should let water out right away.

I'll fire it up tomorrow and see.

Emmerich · #12 10-06-2009, 11:54 PM

My Mercury pissed as soon as it started. So does my Yamaha. It does not wait for the thermostat to open.

Hatterasguy · #13 10-07-2009, 12:02 AM

Thats how it should work.

Judging by house easy he made getting to the water pump sound it must be a fresh water motor. So its probably very clean and like new.

I love going to the lakes and seeing the old outboards. In the salt they last 10-15 years maybe...

mpolli · #14 10-07-2009, 02:35 AM

I was driving to work a few weeks ago and was passing a boat on a trailer. First I noticed it had 4 outboards on it. Then I saw they were each 350 HP. Then I noticed it said Border Patrol on the side. 290 mile range at 60 knots.

http://www.portclintonnewsherald.com/article/20090915/NEWS01/909150318/1002/rss01

SwampYankee · #15 10-07-2009, 09:32 AM

It should be pumping water whether the t-stat is opening or not, otherwise the poor little rubber impeller would self-destruct in no time without the lubrication.

Impellers are cheap and should be replaced every couple of years so I'd do that anyway (they start to stiffen up). If everything is clean and the impeller is new, keep in mind at idle it's still not moving a lot of water but the flow should increase with a several hundred more RPM's.

Quote:

Originally Posted by mpolli

I was driving to work a few weeks ago and was passing a boat on a trailer. First I noticed it had 4 outboards on it. Then I saw they were each 350 HP. Then I noticed it said Border Patrol on the side. 290 mile range at 60 knots.

http://www.portclintonnewsherald.com/article/20090915/NEWS01/909150318/1002/rss01

And those are numbers for public consumption. Imagine what they really are!