Engine Removal on 1988 Sylvan

[Rivergator]

I am in the process of pulling the 4.3 ltr Mercruiser engine from my 1988 Sylvan bow rider. I have arrived at the point where I need to undo 2 more bolts and I am ready for the big moment to lift that baby out of the boat. Not so fast says Murphy and sure enough I cannot loosen the 2 bolts of the rear motor mounts, not to save my life. I tried everything, 1/2" breaker bar, 19 mm impact socket, 2' extension on the breaker bar, applying penetrating oil for a day now and using 2 people, one to hold the socket steady and vertical and me pushing the breaker bar to the point where something will have to give and knowing Murphy's law it won't be anything I can use. And I don't think using my impact wrench will do much better. Am I doing something wrong? Are these bolts always that tight? Where do they screw into? Any suggestions to get these suckers undone is appreciated.

 

[Scott06]

There is a lock nut under the mount that is held in the transom plate. I think if you grind the heads off the bolts you can lift the engine up and out. Once engine is out you should be able to get the nut with the bolt still in it out of the transom plate and just get new nuts ( that doesn’t sound right...)

 

[Bondo]

19 mm impact socket,

Ayuh,.... The heads are 3/4",...... put a pipe extension on yer breaker bar,....

 

[nola mike]

Did you already take the front mounts off?

 

[Rivergator]

Bondo, I think I mentioned that I used a 2 foot extension on the breaker bar. I started out with a 3/4 socket but switched to a 19 mm because it was a hair more tight and I wanted as little play as possible in the socket to avoid any kind of rounding damage to the hex head.
Nola, the front mounts are loose but not removed yet. I was going to wait with the complete removal of the front mounts until that engine hangs on a hoist and I am ready to lift it up.
Scott06, now that sounds like a bummer. Are you sure there is a lock nut under the transom plate? Holy cow, I barely have enough room to get to that bolt. I don't see how I can get in there with any kind of tool, saw, grinder etc. to decapitate that bolt. Do you have a good and clear picture or illustration of the entire rear mount assembly so I can get an idea what this entire gismo looks like and how it is assembled.

 

[GA_Boater]

The rear mount bolts and hardware should be something like this;

 

[nola mike]

The nut is captive in the transom plate. You'd be dealing with it after pulling the engine. Might want to try with the front mounts installed. Or lift/lower the front and try again. If the weight the motor is all on the rear mounts maybe that's putting pressure on those bolts.

 

[Rivergator]

Thanks for the picture. It shows what I wanted to see. I have also done a lot of googling and came across a lot of information and stories of other people having the same identical problem like I am encountering. And the bigger picture is rather discouraging. There is no easy way around it, meaning applying all the torque it will take to either free the bolts or break them. I might try something else if this is even possible to do. I will have to take a good look at this today and see if I can unbolt the bell housing from the motor, pull the motor and then deal with the mounts when it is easier to get to them. Has anybody ever tried this approach and how did it work out?

 

[Rivergator]

Nola, I will give that a try too. So far the front mounts are still in place as usual. All I did was loosen the 2 bolts that mount the front mounts to the stringers on either side. They were the easiest to come loose as both front mounts are pretty much corroded and rusted and will be replaced when the motor is re-installed.

 

[poconojoe]

Maybe you have tried this...shock them loose. Many times I've dealt with stuck bolts and all the extensions, etc. wouldn't budge them, but hitting the extension bar with a lump hammer or small sledge hammer sometimes will shock them loose.

What about applying heat? That helps sometimes, BUT DON'T DO THIS IF THERE'S ANY CHANCE OF IGNITING ANY FUEL OR FUMES!!!!

 

[kenny nunez]

If the bolt is rusted inside of the motor mount bushings you are in real trouble. Hopefully they are not and if you cannot unbolt the housing from the rear of the engine even cutting the heads off of the bolt will not help. I have experienced this many times and the only way is to drill 1/4” holes at the 10 & 2 o’clock down vertically behind the mount bolt close to the outer edge of the motor mount bushing then with a chisel and a good hammer break the rear wall off of the housing. Of course this does the housing no good. But could be re welded together. When I had my shop I usually had a few of the housings stashed in the junk pile so it was no big deal.
I have also used a cutting torch if the bilge was not covered in oil with a assistant holding a garden hose as a last resort.
Needless to say not a very safe thing to do.

 

[Rivergator]

Wow Kenny, now you are really starting to scare me. Looks like unbolting the flywheel housing seems to be the best bet. I will try one other thing before I do that and see if I can get my impact wrench in position to give it the shock treatment. Maybe just maybe it will do the job, but I seriously doubt it. The torch is out of the question, too risky. There is just too much stuff tucked away in that space behind the engine and I will destroy more than I will gain. Once the engine is out of the boat, no matter how I do it, I will then deal with the rear mounts, because I will have easy access to them. I shall know more by tomorrow. It was raining most of the day today.

 

[kenny nunez]

If you manage to remove the engine from the adapter housing I would leave it alone as it is if you still cannot remove the bolts with the engine out of the way. If the the housing does not feel loose as in the center sleeve of the mounts Is not de laminated from the rubber It should still be good.

 

[Rivergator]

Theoretically true, why bother with the rear mounts, its set alignment and position after the engine is out, but on the other hand there will never be another better opportunity to fix these stuck bolts while the engine is out. I will certainly give it some serious thought. Can anyone post a close up picture of the bell housing for a 1988 4.3 ltr showing where all the bolts are that I need to undo and how many there are.

 

[Rivergator]

I have not made any further progress on my rear mounts. Also in addition to that I am struggling to remove my OD. it is stuck good either at the gimbal bearing or the coupler. I am working on that right now to get that drive out. But in the meantime I am still hoping that somebody can post a clear picture of the flywheel housing, clearly showing where the bolts are that screw in to the engine and how many. I may be barking up the wrong tree, but I am still exploring the possibility of unscrewing the flywheel cover.

 

[nola mike]

Here ya go. This is my frankenmotor, so ymmv but pretty sure the bolts and holes stayed the same when i swapped it to the new motor here. 6 bolts. Original had a stud, maybe 2 in place of the bolts. Still wondering if your motor is torqued, esp if you can't remove the drive. Could be way out of alignment. Did you try lifting the front?

 

[tank1949]

Thanks for the picture. It shows what I wanted to see. I have also done a lot of googling and came across a lot of information and stories of other people having the same identical problem like I am encountering. And the bigger picture is rather discouraging. There is no easy way around it, meaning applying all the torque it will take to either free the bolts or break them. I might try something else if this is even possible to do. I will have to take a good look at this today and see if I can unbolt the bell housing from the motor, pull the motor and then deal with the mounts when it is easier to get to them. Has anybody ever tried this approach and how did it work out?

Crank it counter clockwise just as hard and notice what happens. You have rust on the bolts head which may indicate that metals have fused. The nuts on mine were aluminum. You have used a lot of torque which should have stripped the aluminum nuts. I suspect someone has replaced bolts/nuts before and now they are chemically welded over time. Be sure to use 6 point socket. If you have room and an acetylene torch, I'd heat the bolt head after praying. If that still doesn't work, then grind bolt head off. You cannot drive bolt stud back through transom assembly due nut on it and they are inside a keyway. You might break transom aluminum keyway. I went back with ss nuts.

 

[harringtondav]

I have not made any further progress on my rear mounts. Also in addition to that I am struggling to remove my OD. it is stuck good either at the gimbal bearing or the coupler. I am working on that right now to get that drive out. But in the meantime I am still hoping that somebody can post a clear picture of the flywheel housing, clearly showing where the bolts are that screw in to the engine and how many. I may be barking up the wrong tree, but I am still exploring the possibility of unscrewing the flywheel cover.

A trick I learned here is to cut a short length of 2 x 4 so it wedges between the top of the out drive and the gimbal ring with the drive trimmed full down. Then trim up (with the six nuts removed). This should force the drive back away from the bell housing. If still stuck cut a longer 2 x 4 and repeat. If still stuck, your coupler yoke is likely bound in the engine coupler, which gives you a likely coupler replacement to add to your job. Once you get enough clearance between the drive and bell housing, fab up some oak wedges or tree felling plastic wedges and try to coax it off with a BFH.

Removing the flywheel cover to remove the engine could be iffy. You'll need enough space in front of the engine to pull it forward enough so the coupler hub clears the cover when you lift the engine.

 

[kenny nunez]

As the drive goes from L to R the shaft moves in and out a small amount. Disconnect the steering at the tiller bar then have someone push the drive in both directions while observing the shaft for movement. Put your hand on the shaft to feel any movement. If you feel movement then the shaft is bound up in the coupling and the rubber is allowing movement. If there is no movement then the shaft is bound in the gimbal bearing but usually when the bearing is bound to the shaft the gimbal bearing comes out on the shaft.
If the shaft is bound in the coupling then cutting it is your only option. Unbolting the flywheel housing will not still allow the engine to come out.

 

[Rivergator]

Thanks for all the great suggestions. Here is some trivia you all may want to know. I bought the boat 3 years ago but was not able to get to it until now. To my total dismay I have never seen anything in such disrepair, abuse and neglect. The boat itself looked promising, needing some TLC, of course, but when I started in June trying to get it seaworthy I was in for a shock. If this boat had been a child, child protection services would have been called in to action. The engine and/or outdrive is locked, so there is no chance for me to turn anything. Once I get them separated I will see which is locked, if not both. The engine is a pile of rust, at least externally, the alternator is frozen and my first thought was, yank the engine and haul it to the recycling center. But this is not my nature. Admitting defeat and capitulation is not part of my world and I get more stubborn than a pit-bull when challenged. Now I am determined to restore this boat to a presentable state. I wouldn't be surprised if this boat has not been in the water for 10-15 years, that the bilge was flooded at least once at one time. I admit I didn't look close enough when I bought it and now I have to deal with it and I will, one step at a time. Once I get the engine out of the boat I will take it apart and see what the problem is and determine if it can be salvaged, the same goes for the outdrive. As you all know, my problem right now is, both rear motor mounts are frozen solid and the outdrive is stuck in the gimbal housing like it was all one piece and a Budweiser Clydesdale couldn't pull it out. I am working on a number of ideas incorporating all of your suggestions and eventually these obstacles will be overcome, always has in the past. I'll keep you all posted. The good news is that the boat itself appears to be solid and in decent shape. No rot in the transom or other areas that I can see so far but I won't hold my breath.
What I have done so far:
I was able to get to the grease nipple on the coupler and pumped about half of the gun's grease in to the coupler. I hooked the engine to an engine hoist and lifted it about a 1/4" up so I could jerk it around a little hoping that the alpha one would break loose while the outdrive was subjected to tremendous pull. I used the wedge trick (piece of wood between upper unit and transom) but could not use the trim hydraulics because there is no power. And it probably wouldn't have done any good anyway. So I used a nearby tree, attached the outdrive to it with a ratchet and gave it as much tension as I thought I could afford without causing damage somewhere (pictures). The outdrive needs to come out. That is the next move. Until that happens all has come to a screeching halt. Any other suggestions and tricks are more than welcome. Excuse this novel here, but I felt I needed to explain a little more in detail.