1999 Mercury 125 Bluewater Series- Seized?

[peteJ]

Looking for help to troubleshoot seized motor or lower unit:

I realized I ran out of oil at some time during my recent outing. This was evident when I returned home and restarted my engine to flush it out using muffs and garden hose (engine started and ran fine for the one minute of flush) After flush, I checked the oil reservoir in the attempt to top off and it was empty. It was full at start of outing... 1 gallon of oil and about 50 gallons of gas... so I do not believe I ran long without oil. However, this is a new used boat and I was not aware of the oil usage.

A week later I could not turn over motor (appeared to be seized).

I removed fly wheel cover and tried to turn flywheel using a 3 foot bar inserted between to 3 temporarily bolts installed in flywheel puller holes... there is no rotation either way.

I verified the lower unit was in neutral by the prop free spinning in both directions. In forward prop locks CCW and ratchets CW. However when in reverse it is locked up in both directions (is this normal?)

At this time I have removed all spark plugs and I am soaking the cylinders/pistons with Marvel Mystery oil in hopes of freeing motor.

Any help/direction would be appreciated. Could it be the linkage or lower unit is stuck?

Thanks

 

[emckelvy]

Re: 1999 Mercury 125 Salt Water Series- Seized?

Re: 1999 Mercury 125 Salt Water Series- Seized?

It sounds like your lower unit is acting correctly but at this point it might be a good idea to pull it down in order to rule out a problem with the driveshaft or gears.

If the flywheel still won't turn after oil-soaking, you'll need to pull the powerhead as well and split the crankcase halves to inspect for damage.

You may have lucked-out and only seized a crankshaft ball bearing, which is easily replaceable. Unfortunately it's more likely a piston seized in the bore. This motor doesn't have a cyl head so you'd have to remove rod bolts & rod caps in order to separate the crankshaft from the potentially stuck pistons.

One thing you can do is pull the exhaust manifold cover for inspection. Be careful though, if this motor is a Salty Dog, most likely the bolts will be stuck and not easy to remove. If they all come out with normal force, it's quite easy to pull the exhaust cover and inner baffle. You'll then be able to check the exhaust side of the pistons for scuffing/damage as visible thru the exhaust ports.

HTH, let us know what you find..........ed

 

[dutchdog]

Re: 1999 Mercury 125 Salt Water Series- Seized?

Re: 1999 Mercury 125 Salt Water Series- Seized?

You can pull the carbs and reeds and see rod and main bearings.You can also see the cylinders to look for scaring.

 

[peteJ]

Re: 1999 Mercury 125 Salt Water Series- Seized?

Re: 1999 Mercury 125 Salt Water Series- Seized?

EMckeivy, Dutchdog,

Thank you both for the replies and leads. I've been away from home this week, when I get back I will try to rotate again after a week of soaking with MM oil.

If I am lucky enough to get some rotation, shall I work it by hand for a while to free things up then try to start, or is there a more conservitive aproach?

If I get no rotation, I will drain the lower unit oil and inspect for metal fragments. If there are fragments, I will drop the lower unit for repair. If no fragments, I was going to seperate the lower unit enough to disengage the drive-shaft pinion from the ring gears, then try to rotate again.

If all points to the powerhead , does it make sense to pull the powerhead and then investigate as you both have sugested or do you sugest investigating prior to pulling?

Would pulling the carbs and or exhust manifold offer additional lubrication access for the pistons and lower end of motor for a last best effort to free motor prior to pulling the power head?

Thanks again,

Pete

 

[dutchdog]

Re: 1999 Mercury 125 Salt Water Series- Seized?

Re: 1999 Mercury 125 Salt Water Series- Seized?

I have not had my exhaust manifold off so I don't know about access, but going in through the carbs only takes about an hour and it gives you full access to the engine bearings. From what you described I think you will have to rebuild the motor. I would look before I pulled the powerhead. It don't take very long to seize a motor when it is running without oil. Look for discolored rods, crank, bearings,and main caps. I don't think your problem is in the lower unit.

 

[peteJ]

Re: 1999 Mercury 125 Salt Water Series- Seized?

Re: 1999 Mercury 125 Salt Water Series- Seized?

Thanks Dutchdog,

It's looking more and more like the powerhead. I tried to rotate the fly wheel after soaking for about a week, still no luck. I have read some guys try to tap/push the top of the piston with a brass or relatively soft rod through the spark plug hole... has anybody had uny luck with that? How about compressed air through the spark plug hole? I supose if I had a threaded rod with a soft bottom, I could try screwing preasure on each piston ...anybody try that? I will still try to drop the lower unit. I'm trying to figure out where to disconnect the shifter linkage... anybody know? This is a new used boat to me and I do not have a manual. I drained the lower unit oil, first removing vent, lots of MM oil from the motor drained first followed by about a pint of gerar oil and no metal fragments.

Thanks
Pete