25 Mercury XD stuck after sitting a week

[outlawfox13]

Ok so I have a new to me Merc 25hp XD serial 0A911375. I bought at an auction. I brought it home had good compression 120-125 ea. Took it out for a few runs and it ran great on 50:1, water came out pee hole the whole time. On the last few starts it would give me a hard start like a clogged pilot jet. Also on the way back it was sputtering like a dirty carb or bad spark. I finally got a chance to take the carb apart a week later and found it clean, so I checked comp. When i went to pull start it and it was like a frozen block. So I tapped the fly wheel with a mallet and wooded block an she started to move. I stopped to check and it pull started freely, so I did a comp check and was at 90 top and 125 bottom. I then added a few tsp of 2 stroke and psi on the top went to 115. I let the motor sit for 2 days and now it will not pull start. Does anyone have an idea on what happend. Thanks in advance

Mike

 

[jbjennings]

Re: 25 Mercury XD stuck after sitting a week

Take off the exhaust cover and look for a pinhole in the inner cover due to corrosion, or a burnt or bad exhaust cover or inner cover gasket. I'm thinking the lower crank seal can be a problem on the xd's, but that doesn't sound like the problem on yours since the top cylinder was showing bad compression. That's about all I can think of.

 

[outlawfox13]

Re: 25 Mercury XD stuck after sitting a week

The earliest I can look is Tuesday. Would this cause the motor to act like it is seized? I was wondering whether water seeped into the top cyl and is allowing it to rust.

 

[jbjennings]

Re: 25 Mercury XD stuck after sitting a week

Any water entering the cylinder could cause the rings to rust to the cylinder walls, so yes. There's no head gasket on your motor so that couldn't be it. I can only think of the exhaust covers or lower crank seal letting water in, and your top cylinder was most affected so I'm thinking the former is probably it.
GOod luck,JBJ

 

[outlawfox13]

Re: 25 Mercury XD stuck after sitting a week

Thanks I will take a look as soon as I can.

 

[outlawfox13]

Re: 25 Mercury XD stuck after sitting a week

Ok here's the deal. I went to remove the exhaust cover and the bolts were not even hard to loosen. Im not even sure they were torqued down. Next I was looking at the top cover and it appears that the gasket is not correct. Look at the pics and tell me what you think. Also now that I got a look inside I could see water entered both cyls, and the bottom piston is scratched up. It is scratched below the piston rings and slightly on the rings. This was the cyl with the best compression so im at a loss. Water was definitely getting into both cyls because both plugs showed water and corrosion. Ok so here are the pictures. Let me know.

Mike

 

[outlawfox13]

Re: 25 Mercury XD stuck after sitting a week

The top cylinder did not appear damaged at all. Also there were no scratches inside the cyl walls. It appears that there are 2 different gaskets(serial group #1 and #2) and it is possible someone order the wrong one.

So any and all help is appreciated.

Mike

 

[CharlieB]

Re: 25 Mercury XD stuck after sitting a week

Two schools of thought;

First is to tear it down completely so you can do it all at once, completely. Hone the cyl's, buff the marks on the pistons and mic them, mic cyls, then decide whether you need to replace pistons or not, definitely new rings, the correct gaskets.

Seconds is get the gaskets, reassemble fire it up and do a heavy decarb. Recheck compression, run the motor until it really needs a rebuild.

Personal choice, check the ring tension on #1, if it seems to be a lot of carbon in/on the rings then go with the Second option.

It is hard to gauge the damage on the cyl bore. There are a few cameras available on ebay for 20 that you can poke in the spark plug hole to get a view, plus what you can see thru the exhaust ports, if the cyl doesn't look very bad then try the decarb, run the motor a little while then retest compression.

 

[jbjennings]

Re: 25 Mercury XD stuck after sitting a week

I personally would tear it down since it's stuck now and you know it's got water in it. You can tell then if you've got rust on your crank or rods, besides getting a look at those pistons and ring grooves. With that much scoring, I think you may have built up enough heat to hang a ring on a port. Even if it didn't break the ring, it could have squenched the lands down on a small section of the rings and prevented that area of the piston from sealing. If I were going to tear it down at all, I'd do it immediately to see if you can prevent any pitting of your crank or rod journals. If that happens, a rebuild could exceed the cost of a good used block or good used motor.
Now that's just my opinion, and I'm just a hobbyist and have only rebuilt a handful of motors, so......
Good luck and sorry for the rotten discovery,
JBJ

BTW, yes, it appears to me that the gasket was defiinitely wrong. Exposed sealing surfaces with nothing on them with the current gasket. I'm surprised that water didn't kill your spark before the damage was that bad. I guess the water entry was just right to be just wrong. Seems like those motors almost know just how to get boogered up in the worst way possible.

 

[carholme]

Re: 25 Mercury XD stuck after sitting a week

Your s/n comes up as:

MERCURY - ( 25 H.P. (1986 ))
Serial No: 0A911375 Model No: 1025206

Parts List for model 1025206:

18/20/25 H.P. (XD) - Mercury, Mercruiser, Force, etc. Parts Lookup

See that your s/n under MISC. PARTS / SERIAL GROUP CHART is a serial group 2 engine. The manifold you are showing in the photos above is a P/N 92329 which is for a serial group 1 engine.

As you have the parts there, you may want to examine both CYLINDER BLOCK AND COVERS (SERIAL GROUP #1) and CYLINDER BLOCK AND COVERS (SERIAL GROUP #2) to see if you have the wrong covers/manifolds and gaskets installed for your s/n.

Gerry

 

[outlawfox13]

Re: 25 Mercury XD stuck after sitting a week

Ok so it looks like I have a cover and exhaust manifold for a group 1 engine. And a gasket from a group 2 block. This explains why it leaked. Ok now can I use these on my block if I order the proper gaskets, or is there a reason why my block has to have the group 2 manifold and cover. Thanks.

Thanks carholme for pointing that out.

Mike

 

[outlawfox13]

Re: 25 Mercury XD stuck after sitting a week

Does anyone know if this exhaust manifold will work? Or do I need the correct one?

Thanks.

Mike

 

[carholme]

Re: 25 Mercury XD stuck after sitting a week

I can't tell you what to do but here is a series of pictures of the correct manifold:

2000 Mercury 25HP Exhaust Manifold PN 92329F03 CN 92329 C1 $20 00 Free Shipping | eBay

The correct cover:

923301 Cylinder Block Side Cover Mariner 25HP Outboard | eBay

Compare those to the units you now have and the problems you have encountered with the engine. When you said that the bolts were not even torqued and you picked it up at an auction, it sure sounds like someone slapped on whatever they had to make a complete looking engine.

At the price of the units you require, I would get them pretty quick if it were my engine. You can take the part numbers and see if you can find anything closer to your location.

Gerry

 

[outlawfox13]

Re: 25 Mercury XD stuck after sitting a week

Thanks Gerry,

Yea I found a set on fleabay as well. I was just wondering if running the manifold and cover I have now with proper gaskets would still work. But I think safest bet is to order the proper set. Thanks for the help everyone.

Mike