55HP Chrysler '76 557HG seized

[inkdbeard]

I am new to iboats and this is my first post. I have looked and did not see any previous posts pertaining to my issue, but should one exist feel free to redirect me. As the title suggests, I have a 55HP 1976 Chrysler 557HG. I got it from a coworker who let it sit for 2 years but ran fine the last time he had fired it up. How recent, I am not sure but within the last year. It was stored outside but the exterior looks O.K. Inside the cover, all looks well. However, it will not turn over. And by turn over, I mean by hand. It has not been connected to a battery or given power but it is almost as if, for all intents and purposes, we will say it is, seized. I am stumped as to why. It is not at TDC and the portion of the cylinder walls that I can see look good. I can't turn the flywheel by hand, with a power bar or an impact gun. I am mechanically inclined but most definitely not a mechanic. Is it possible it is not seized and my issue lies elsewhere? I fear he ran it with too little or no oil and did not winterize it. I expect I'll have to tear it apart, but am concerned with availability of parts.

Any info or help will be greatly appreciated.

 

[pnwboat]

Parts are definitely hard to get as they have been out of production for many years. Especially the major engine components like pistons, rings etc. Many of the other parts like water pump impeller, fuel pump diaphragm, head gasket are still available.

Usually, if the motor is seized from sitting, the piston rings and cylinder walls are rusted and will prevent the motor from turning over. You might be able to free it up if you set the motor horizontal with the spark plugs pointing up. Take the plugs out and pour some CRC or rust buster penetrating oil into the spark plug holes and let it set for a day or two. Then try spinning the motor by turning the flywheel. May take several days of repeatedly doing this to free it up. If you do get it to turn over, you'll want to check the compression. If it's 100LBS or higher, you might want to consider keeping it, however, it'll be a good idea to replace the fuel pump diaphragm and water pump impeller.

NOTE: There is a remote possibility that the motor itself is not seized, but the gears or bearings in the gear case are seized preventing you from turning the motor over. You have to remove the gear case to find out. If you need a replacement gear case, you may be able to find a used one on-line at some of the auction sites.

 

[inkdbeard]

If I try and turn the flywheel it almost sounds like it's got some play but the pistons aren't moving at all. I have some rust buster in there right now as we speak. It's been weeks of repeatedly adding rust removal products to the cylinders and trying to turn it over. I guess removing the gear case to check can't hurt - as long as I can get the gaskets and seals.

 

[wickware]

No Title

1. I see you have add light wt oil and rock flywheel back and forth to try and make a turn t or more?
2. If you can not get a turn, pull the flywheel to know it is not the problem.
3. I have left my 1970 35 HP Chrysler stored 2-3 yrs w/o a problem so far. My 35 HP could be as your 55 if it only has one Carb (larger piston bore, stroke, short leg). ?Used parts? seem to be out there. Attached is my example of long lower unit, one carb and only the cover is off a 55 HP.
4. I experienced one experience of an 80 HP locking I feel was from too little oil. Once we forced it to turn with a good mix, it ran the next 5+ yrs until retired.
5. Do you know an aircraft mechanic with a camera that will view inside the Cyl?
6. Good luck ! These monsters are Tuff ?IMO? if they are not constantly misused.

 

[pnwboat]

Not sure about exactly what's involved in removing the lower unit on that particular motor. Somewhere I think I've seem something about one stud that seems to be a problem but not 100% sure if that applies to your model.

If there is no movement in the pistons at all, then most likely they are seized in the cylinder bore. You might be able to get the pistons unstuck by removing the head and applying pressure to the tops of the piston to push them down. Maybe a 2 X 4 and gentle tapping with a hammer. Replacement head gasket is around $40 though.

 

[inkdbeard]

1. I see you have add light wt oil and rock flywheel back and forth to try and make a turn t or more?
2. If you can not get a turn, pull the flywheel to know it is not the problem.
3. I have left my 1970 35 HP Chrysler stored 2-3 yrs w/o a problem so far. My 35 HP could be as your 55 if it only has one Carb (larger piston bore, stroke, short leg). “Used parts” seem to be out there. Attached is my example of long lower unit, one carb and only the cover is off a 55 HP.
4. I experienced one experience of an 80 HP locking I feel was from too little oil. Once we forced it to turn with a good mix, it ran the next 5+ yrs until retired.
5. Do you know an aircraft mechanic with a camera that will view inside the Cyl?
6. Good luck ! These monsters are Tuff “IMO” if they are not constantly misused.

That's exactly what my motor looks like and I believe my father in law has one of those cameras. I think he tried to pull the flywheel but could not get it to come loose.

 

[wickware]

No Title

With the shifter in neutral or shift rod on the engine (center position) the prop should spin to say the lower unit is not locked.

Pulling the flywheel can be a challenge. With a good Harmonic Balance puller and penetrating oil it will usually come off. ?Be careful?! ?It Really Comes Off At Times?. My Universal Puller and Break-Over has not had a problem since 1984 to ck the points. You might break a bolt but replace it and add good torque, popping with a hammer occasionally. My boat has been in a fresh water only environment that might make a difference.

Know your torque to replace the flywheel (80 ft lbs is what my Clymer shows but verify that). Use lapping compound if it appears it was not matting good. While you are in there ck your points if it has points.

Any ideas of hours per years and services on the motor. I ran 6 -12 gallons per summers only 1984 ? 2012 when I fished. A Good Hard Running 4-5 mi and Staybil was good for it before I left the lake (after just running trot-lines or fishing close spots. With Stabil mixed for a years storage, I stopped running it ?Bone Dry? Season ?Season. Not to mentioned the previous owner?s instructions of running it ?Bone Dry, Trip ? Trip?, which was a waste of gas IMO!

Too Much To Proof. LOL!!!

 

[inkdbeard]

Wick, the prop spins with no resistance in neutral. Father in law has broken a puller trying to remove the flywheel. Would it be possible to heat it up and lube it to remove easier?

 

[Nordin]

Best way to check if it is the engine or the LU that is seized is to drop the LU.
If the prop spins in neutral it only shows that the clutch and shiftrod is working.

The seizing can be in the engine (crank, pistons) or in the LU (piniongear bearing).
The piniongear in LU is always in connection with the engine crank, even if the shiftrod is in forward, neutral or revers.

SOO you have to drop LU first to check if the seizing is in the engine or LU.

 

[tommarvin]

Like above, you can drop the lower unit in five min. Is the LU seized, the odds favor not seized.
2. Like above, the motor needs to be on the ground spark plug holes up at 12 o,clock, pour in Marvel mystery oil in each spark plug hole 1/8 inch high, it's at auto parts stores.This stuff is amazing,i don't know how long to let it sit in there, when you loose you patience put a socket on a breaker bar and try to break it free clockwise then counter clockwise. if it won't move, like above, your going to snap some bolts off to remove the head. Get a two by the full width of the piston and gently tap all piston hears, try breaker, tap harder try breaker bar again, it will break loose.
Then check with compression test.

 

[jerryjerry05]

When you pulled the plugs was there ANY rust on the plug?
If not then drop the lower.
There is a big bearing on top of the crank that can seize???

Install the puller and try to remove.
When you have as much pressure on the puller as it can take??
Then a 3# hammer on the puller bolt.
Most times the shock will break it loose.

 

[inkdbeard]

Update: the spark plugs have no rust and according to my father in law when he first removed the head there was zero rust on the piston heads or cylinders until he put vinegar in there. I've since soaked in light weight oil but I'm having a hard time removing the lower unit from the engine. There are multiple bolts around the underside of the engine and two, what I strongly assume to be engine mounts). They don't seem to want to come free. What am I doing wrong?

 

[jerryjerry05]

There is a coupler on the shift rod.

 

[inkdbeard]

To separate it in the middle?

 

[wickware]

No Title

1. My L/U will drop if I remove 4 bolts that is a must.
2. ?Plus?, Rem the cotter in the shift rod ?OR? Rem the coupler in the back of the leg is an option.
3. My pref is to use a longer bolt and nut to hold the L/U while I rem cotter vs re-centering coupler.

 

[tommarvin]

I would do wickwares plan, remove cotter key, don't touch the coupler.
Get a socket and breaker bar for removing seized bolts.

 

[jerryjerry05]

A breaker bar for removing seized bolts on an outboard will result in broken bolts and rounded off heads and a LOT more work.
​That's the same as using an impact on an outboard.NOOOO

If it can't be loosened with a1/4 or 3/8 drive socket and normal pressure?? Then you need to be careful or it'll strip or twist off anything you work on.
A difficult bolt will need heat, lube(PB Blaster/ WD-40) and a hammer(small) and time.

 

[inkdbeard]

I have some pictures that need resizing but the four bolts came free without an issue and the prop and shaft (to the engine) are now separated. I'm unsure of the proper term but the leg or whatever that the shaft goes through that mounts to the casing around the engine is proving difficult to remove. I am now trying to separate that and the engine. Disassembly of the engine is looking to be necessary. Going to get out the snake camera tomorrow.