Merc 200 1964 (20hp) help needed - flywheel won't move at all, but used to.

[suznjames]

Hi, I need some help with an old 1964 20HP Outboard Mercury that I'm trying to get working.

I recently bought an old 1964 Merc (SN 1652807); which supposedly ran last year but had not been tried this year (for not much $, so I did assume some work is needed). Spark plugs looked bad so I did those (autozone alternative - don't remember the one they picked but that's not the current issue ) Before it was running (and not sure how many times it was ran) it was sitting in a barn for X years. Reason for selling from previous guy was that it was on an inflatable boat; which crimped in 1/2 with 20HP - since been replaced with 2 HP motor

Anyway, when testing when I got it home (in a trash can of water), the rope starter pulled fine (not an easy pull, but not insanly hard); but I couldn't get it started. Flywheel turned ok; but I did notice leaks of gas on one line; and also in the Carb overflow (so I assume a carb rebuild is worth it and also maybe a new float since it looked stuck due to the overflow... ?) However, again, that's not my current issue but I'll ask for help there in a while.
I didn't have a compression tester at the time but my thumb over the spark plug holes incicated pretty good pressure when turning the flywheel. I was going to try real compression test after I got back from vacation....

So then I went on vacation for 2 weeks and left it in my garage; but when I get back I couldn't budge the flywheel at all in either direction, in any gear with my hands pulling the rope, or trying to rotating the flywheel. Before I left it was turning Ok, but just not starting. Hence my current worry is what is causing it to not turn at all; and if I can get that solved then I'll look at starting it and fixing the gas lines I have tried taking the flyweel off and didn't see anything bad (but didn't have an extractor so just took off the 6 bolts on top to look). I also then tried to take the lower unit off, and after some searching it came off Ok - lower unit turns Ok but flywheel still is stuck. Removal or insertion of spark plugs has no effect; and both cylinders are approx in the middle at the moment - one slightly further in than the other. So I assume it's something in the top part, and it's not the cylinders hitting the spark plugs.\...

Any ideas? Is there a lock somewhere I tripped while looking at it? Anything else to try that anybody would suggest? I doubt it's really serious since it stopped when not running; but anything is possible. My next guess is to just start taking apart the top unit and see what I find; but if there are any suggestions first they will be very welcome.

Or should I take some rust spray and a hammer

Please ask questions and let me know if any more info or pictures are needed. I don't want to spend too much time on the carb if the flywheel is stuck and it will never work...

Thanks,

James!

 

[oldman570]

Re: Merc 200 1964 (20hp) help needed - flywheel won't move at all, but used to.

If the flywheel was turning and the pistons were moving before you took the flywheel off and then replaced it , then I would be taking the bolts out one at a time and see if they might be hitting on the coils or other parts under the flywheel. A compression test gauge and flywheel puller can be borrowed at most large auto stores to do the test and pull the flywheel. Always run a compression test before spending $$$ on a motor that has set and could only make a good anchor. Oldman570

 

[Toddboat]

Re: Merc 200 1964 (20hp) help needed - flywheel won't move at all, but used to.

You didn't remove the flywheel until it didn't turn, so it prolly has nothing to do with you removing the flywheel.
When first reading your explanation, I was thinking it was a gearbox issue, but if you've removed the LU and it still didn't turn, then that's not the problem. So now I'm thinking one of two things...
1.) Check the starter, make sure it's disengaged from the flywheel. I am thinking this because this is one of the few parts you moved that could have had an effect. Check this first because you don't want to damage the starter by trying the next idea.
2.) It could simply just be harder to turn than in the past because of where it landed. If both cylinders are roughly at midstroke, then it could be hard to overcome the static friction to get it moving because you're starting with the least possible crankshaft length, if that makes any sense. I think it would turn (with some effort) had it landed at TDC.
There's possibly a lot of carbon buildup in the cylinders that makes the rings (pistons) get stuck.
Spray some WD-40 or PB Blaster in there and get it moving. Once you get it running, decarbonize it asap. Who knows if it was ever decarbed at all. Most people never do it. Seafoam is one possible way of doing this.
Oh, and P.S., change the floats, they are prolly cork coated with shellac which doesn't hold up to ethanol. Always add fuel stabilizer when fueling up.

 

[suznjames]

Re: Merc 200 1964 (20hp) help needed - flywheel won't move at all, but used to.

If the flywheel was turning and the pistons were moving before you took the flywheel off and then replaced it , then I would be taking the bolts out one at a time and see if they might be hitting on the coils or other parts under the flywheel. A compression test gauge and flywheel puller can be borrowed at most large auto stores to do the test and pull the flywheel. Always run a compression test before spending $$$ on a motor that has set and could only make a good anchor. Oldman570

Actually, the flywheel was turning and pistons were moving before I left on vacation for 2 weeks; then didn't move afterwards. I took the flywheel off after they didn't turn (when I got back from vacation) to look into what was happening, to see if I could see any obstructions - but didnt find any yet. After taking it off (the 6 bolts and cover, not the actual part which needs the removal tool yet or the center bolt as I don't have the removal tool yet) - I could still not move anything.

The only difference between turning and not turning was 2 weeks in my garage, and that I was looking at the fuel line that was leaking...

James.

 

[suznjames]

Re: Merc 200 1964 (20hp) help needed - flywheel won't move at all, but used to.

You didn't remove the flywheel until it didn't turn, so it prolly has nothing to do with you removing the flywheel.
When first reading your explanation, I was thinking it was a gearbox issue, but if you've removed the LU and it still didn't turn, then that's not the problem. So now I'm thinking one of two things...
1.) Check the starter, make sure it's disengaged from the flywheel. I am thinking this because this is one of the few parts you moved that could have had an effect. Check this first because you don't want to damage the starter by trying the next idea.
2.) It could simply just be harder to turn than in the past because of where it landed. If both cylinders are roughly at midstroke, then it could be hard to overcome the static friction to get it moving because you're starting with the least possible crankshaft length, if that makes any sense. I think it would turn (with some effort) had it landed at TDC.
There's possibly a lot of carbon buildup in the cylinders that makes the rings (pistons) get stuck.
Spray some WD-40 or PB Blaster in there and get it moving. Once you get it running, decarbonize it asap. Who knows if it was ever decarbed at all. Most people never do it. Seafoam is one possible way of doing this.
Oh, and P.S., change the floats, they are prolly cork coated with shellac which doesn't hold up to ethanol. Always add fuel stabilizer when fueling up.

I don't think the starter is the issue; since the rope is part of the cover (shell) which is removed when I try to turn the flywheel; this used to move by hand (hard) but now does not move at all by hand with as much force as I can apply by hand. I would describe that it had a lot of resistance to move (i.e. 20%), but now has 100% resisntance and I can't budge it by hand. I haven't tried tools to move it in case I break something, but if that is suggested (or nothing else works) then I'll try it.

Option 2 could be an option and the reason does make sense. Does it show any light if I say the previous owner sprayed it with WD40 last year for winterzation - I'm not sure what should be done as I've not looked it up yet. (I've not owned a motor for a year yet I would not be supprised it if hasbn't been decarbed at all, nor had any other maintenance done. If I can see that it can work, then I'll get whatever needs to be done.

Can I get Seafoam at an autostore, or an alternative, or is this a custom/shipping item?

Thanks!

 

[suznjames]

Re: Merc 200 1964 (20hp) help needed - flywheel won't move at all, but used to.

And also - yes, that's correct that the issue happened before I removed the flywheel

Thanks!!!!

James.

 

[suznjames]

Re: Merc 200 1964 (20hp) help needed - flywheel won't move at all, but used to.

And also - yes, that's correct that the issue happened before I removed the flywheel

Thanks!!!!

James.

The option 2 would also tie in with the fact that it was hard to turn to start off with... I'm comparing with the current one on my boat (Evinrude 9.9HP 1975), which on a hard to turn scale I would put 3. The Merc - when it did turn I would give a 7, and now after the vacation it's a 10. Where 1 = no resistance to 10= unable to move.

Hence maybe with landing in the middle; plus WD40 previously applied and now dried after 2 weeks has caused it to freeze up....

James.

 

[Chinewalker]

Re: Merc 200 1964 (20hp) help needed - flywheel won't move at all, but used to.

Did you at any point try to use starter fluid in this motor when you were trying to start it initially? Starter fluid rinses residual oil away and the ether can attract moisture to those now bare surfaces. Any chance your gas had water in it? Was there oil mixed with the gas at a 50:1 ratio? Sounds to me like something rusted up while you were gone. Generally, bad things happen to motors that rust up enough inside to seize the motor. Even freeing it up with your favorite penetrating oil will likely result in a short lifespan for the motor. In my opinion, the ONLY way to properly free up a motor is a complete teardown for inspection of all bearings and bearing surfaces.

 

[steviethev]

Re: Merc 200 1964 (20hp) help needed - flywheel won't move at all, but used to.

Sounds like there wasn't enough oil coating the rings / cylinder walls and perhaps having the plugs out created enough moisture to cause the rings to rust to the cylinder walls.

The correct way to solve this would be to completely tear apart the motor and rebuild. However, that can be timely and expensive, especially on an older motor.

I have had some success on car engines using a liquid (not the spray can) penetrating oil poured into the cylinders through the spark plug hole. The motor must be tilted so the piston top is as close to horizontal as possible. Let the oil sit in there for a a few hours or a day. Then you can carefully put a wooden dowel in the spark plug hole and LIGHTLY tap on the piston - don't go whacking it. Just a light tap. Then get a big pole or board, attach it to the flywheel, and gently work it left and right until the pistons start to move. Again, never done this on a boat motor, but have on several seized car engines with success. Can't speak to the life of the motor, but they're still running.

Again, the CORRECT way would be a complete tear down and rebuild.

 

[steviethev]

Re: Merc 200 1964 (20hp) help needed - flywheel won't move at all, but used to.

Also, WD-40 is a terrible thing to let sit in a cylinder. It's hygroscopic and will draw moisture into the cylinder and around the rings causing them to rust.

If you use it to free up parts, once they're free, immediately follow with a quality lubricant.