Topic: Siezed 25 hp Mercury help (Read 3572 times)

dudesikoff · « **on:** November 23, 2009, 07:50:57 PM »

Hi, I have a 25 hp mercury that I want to put on my 17' stumpjumper. Problem is it's siezed. I just wanted to know what id be getting myself into trying to unsieze it. If I should try to fix it or just buy a new one, (i only have 500 dollars and i need to buy other stuff for my boat.)

Dave · « **Reply #1 on:** November 24, 2009, 08:08:54 AM »

Hi dudesikoff and welcome.

Un-seizing your motor depends on how it go that way.

Did it seize from sitting around too long and rust stuck?
Is it sized from over heating or broken piston or rod?

Knowing the answer will make a big difference on the remedy and cost.

I would start by using a lot of penetrating oil down the plug holes or hole and let it sit for at least a week or two.
Then try turning the prop while in gear to see if you can loosen the motor up.

If not, you will have to force the power head off to determine the damage.

If the motor is seized from rust and you get it loose you might be in luck and just cleaning the cylinder walls and maybe new rings and you are done.

Let us know how the motor got sized.

dudesikoff · « **Reply #2 on:** November 24, 2009, 12:41:11 PM »

Well, I was given the boat and engine by a friend. And they told me that it ran at one point but that hadnt been for several years. I'm about 99% positive that it rusted as its been sitting for years (but there was no gas tank attatched, dont know if that matters or not.) If i wanted to unsieze it and possibly rebuild it how much would i be looking at?

Dave · « **Reply #3 on:** November 24, 2009, 06:30:38 PM »

Pull the plugs and put some penetrating oil in the cylinder and see if you can get it to turn over by hand.

If you handy or mechanically inclined you can rebuild the carburetor.
Hopefully the electrical system is still ok.

With any luck you will not have to spend a whole lot of money, but you will not know until you can get it un-seized.
Just don’t force anything to the point of causing more damage, allow the penetrating oil to work.

dudesikoff · « **Reply #4 on:** November 24, 2009, 11:32:10 PM »

what kind of penetrating oil do you reccomend? 2 stroke oil or marvel mystery oil?

Dave · « **Reply #5 on:** November 25, 2009, 07:57:24 AM »

WD40 should work.

Gone FishN · « **Reply #6 on:** November 25, 2009, 12:56:05 PM »

I use and like a product called Corrosion X.
Not only should you apply penetrating oil in the cylinders, you should apply the oil to all nuts, bolts and any part you will be removing.
Allow the oil to soak for at least a week, reapplying every day or so.
As mentioned don’t force any part to avoid damage or breakage.

dudesikoff · « **Reply #7 on:** November 25, 2009, 01:15:23 PM »

i also remember being told when i got thr boat and engine that it needed some type of gasket or seal, i forgot, but i told my friend to ask his dad so hopefully ill find out soon enough

Just Steven · « **Reply #8 on:** November 25, 2009, 02:01:08 PM »

I had to do all most the same thing. I use lots of wd40 all over the motor. If you pull the cylinder off you will need new gaskets.
I need to rebuild the carbaratos.
The rings were ok so I sanded the cylinder wall with very fine emery cloth sandpaper and oil.

dudesikoff · « **Reply #9 on:** November 25, 2009, 08:01:53 PM »

I saw on craigslist some guy is gonna trade a mercury 25 in realllll good shape for a smaller motor like a 15 and i have a nice 15 evinrude that runs, should i go for it?

Dave · « **Reply #10 on:** November 26, 2009, 09:10:22 AM »

If you motor does not require much work or money to get it going it still might be worth fixing it.
Good luck in whatever you decide.

donahue_85 · « **Reply #11 on:** November 26, 2009, 11:03:52 PM »

My opinion is to use the Marvel Mystery Oil. Let it soak ATLEAST overnight, then try to take a socket & breaker bar to the nut on top of the flywheel to turn it over by hand. As said, DO NOT force it!!

Let the oil do it's thing.

It WILL eventually break free if the issue was caused from rust or build-up. I have been in your predicament before, so I speak from experience. If the overnight doesn't work, try it one more night, if this dosn't work with the mystery oil, you have bigger issues. If so, get rid of it or keep it for parts. More than likely, from the sounds of it, you said you needed a gasket, It's sounds like it was overheated at some point & it is in need of a head gasket. This is a cheap thing to fix & not too time consuming, but depends if your willing to do the work or not. Try the oil first! Let me know what happens, I will let you know what your issue is to the best of my knowledge.

BobD · « **Reply #12 on:** November 27, 2009, 03:17:23 PM »

I second the marvel mystery oil. I'd take the head off and take a look at the cyclinder. It will be easier to soak it with oil and it'll cost you a gasket. Just don't snap the bolts. If it doesn't move after a few days of soaking, you probably have rod bearing issues or worse.

dudesikoff · « **Reply #13 on:** December 01, 2009, 12:47:13 PM »

well i got my sisters boyfriend to look at it and he told me that it is siezed (obviously) but said there is some hope for it so once i can get the motor over to him ill update on how the progress is coming. But im starting to have seond thoughts on a 25 because wouldnt a 450+ pount boat put a bit of strain on an older 25?

donahue_85 · « **Reply #14 on:** December 01, 2009, 01:13:04 PM »

Does your boat have a capacity plate? It should tell you the maximum HP & weight the boat can hold. If not look it up to find out the max HP, that should give you an idea of how much power you should need. For example, if it can hold a 50HP as its max HP, then you should be ok with a 25. Look into this if your concerned about your weight to HP ratio. It'll atleast give you a guesstamation.

Dave · « **Reply #15 on:** December 01, 2009, 08:00:54 PM »

You might be right, 25hp for a 17' boat might be a little small.

But a small motor is better than no motor.

dudesikoff · « **Reply #16 on:** December 11, 2009, 12:32:12 AM »

Well heres an update, I put my 15 on craigslist and have gotten multiple offers, also have gotten and offer on my kicker bracket. So im hoping to make around the 550 to 600 dollar range which is really good! Now I can buy a 30-40 hp which is what ive needed. Now i have a new dilemma, what brand of motor to get. I saw a 30 hp 2002 johnson for 900 with controls and i reallllyyy thought it sounded good, can i get some feedback on what are good motors and what to stay away from.

Thanks

Angler · « **Reply #17 on:** December 13, 2009, 12:12:37 PM »

Never owned a small motor that size, but the same should how true.

Low hours, good compression, check the plugs.
Electric start!

Good luck.

dudesikoff · « **Reply #18 on:** December 13, 2009, 06:52:16 PM »

Well i saw a boat for sale for $800, its not the boat i want its the motor, Its a 93 Suzuki 40 horse with steering i assume. I was wondering what anybody thinks about the 93's because I was told to look for an older Suzuki because of its all (cast iron?) and bronze construction. I'm not sure if the 93 was built this way, can anybody help?

donahue_85 · « **Reply #19 on:** December 14, 2009, 01:46:39 PM »

In my opinion, Suzuki's are junk to begin with. If I were you I would try to sit on your money until you can find a Yamaha or Merc. Yamaha's hardly ever have problems at all & Merc's, if something is to break on them, parts are a dime a dozen!

Keep that in mind.

dudesikoff · « **Reply #20 on:** December 16, 2009, 12:29:17 AM »

with that being said i saw a 1992 yamaha for 1150 but it had no controls :(and at most ill have 1000 unless my friend will pitch in money

donahue_85 · « **Reply #21 on:** December 20, 2009, 08:26:18 PM »

A set of controls for that will cost you almost half what the motor would be costing you. You should wait for something good to come along. Good things come to those who wait!

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Author Topic: Siezed 25 hp Mercury help (Read 3572 times)