Unable to align 496 engine on 280 Sundancer

Danny Troy

Danny Troy

Member
Oct 8, 2009
861
Candlewood Lake, CT
Boat Info
2003 280 Sundancer
Engines
496MAG w/genset
Despite the cold weather I thought I'd get a jump on getting the boat ready to re-install my outdrive in the Spring, and thought it would be a good idea to align the engine. The drive was also difficult to remove, and required using a scissor jack to get it off. I found that regardless of how I adjusted the front engine mounts, I was not able to get the drive alignment tool anywhere near complete insertion. I even tried the old yoke, and same story. I wonder if the rear mounts are out of adjustment, or require shimming or replacing? I'm worried that if I can't insert the alignment tool all the way, trying to install the 175lb drive will be a nightmare. The posted photos are the both
port_rear_engine_mount.jpg
starboard_rear_engine_mount.jpg
rear mounts.
 
Looks to me like those rear mounts are history ! Open up the check book and get some new ones. Even if you could get the outdrive reinstalled with the mounts in that condition the shaft and or hub wont last long at all. Last hub i replaced was about $750.
 
Yes, I was suspecting the rear mounts were gone. Now the question is, can the mount be changed without removing the engine? Will lifting the engine slightly give enough clearance to do the replacement? The starboard mount looks like it will be tough to get to.
 
We had the transom assembly replaced on our 280. What amazed me was both the size of the 496 (frickin huge), and how simple and quick it is to remove and replace.

So at this point I’d pull the engine all the way out and replace all the mounts. The one place I would most not want to be is inside a 280 engine compartment with a 496 engine hanging above me. Besides to just lift the engine you’ve already done 99% of the work to get it out on the ground.

While the engine is out, replace all of the little stuff on the engine that will take a fraction of the in boat time. These are things like the starter motor (requires engine removal to replace), all of the little water hoses and clamps etc. you can also clean, scrap and paint any rust spots, as well as really clean the bilge. And don’t forget the water heater. It is written in stone that the water heater will fail within 12 months if you don’t do it when the engine is out.

Any way, as they say that’s my $0.02.

and don’t forget the water heater
 
At this point I guess I'll wait until the Spring and probably have my marina take a look at it. I just did the JR Marine method of swivel shaft replacement, as well as new bellows, new yoke and u-joints, new trim senders, new gimbal bearing, as well as some seals. I'm finished for the Winter and will deal with the rest in the Spring (boat is shrink-wrapped). The funny thing is that when looking through the gimbal bearing (bellows not installed yet) it looks like the coupler is too high. If the rear mounts went bad, I would think the rear of the engine would have dropped. Adjusting the front mounts to bring the rear down doesn't bring the coupler down far enough. That's just eye-balling it though. I'm thinking my next boat will be an outboard!
 
If it looks high it's probably not the rear mounts. You probable need to tweek the gimbal bearing into alignment. New ones are very stiff.
 
As stated, new gimbal bearings are very stiff. I had to insert my alignment bar as far as possible then smack it with a big hammer on the sides while turning it to get it even grossly aligned. It took a while until the bar would go into the coupler enough to begin the alignment.
 
The old yoke enters the spline in the coupler, but still has and inch or two to go. The alignment tool seems to get hung up even before it goes that far in. At any rate I'll try again tomorrow to set the new gimbal bearing. So far, hitting it with a good sized rubber mallet hasn't moved it at all. I'll give it one more try before I give up for the rest of the winter.
 
OK, just tried the pipe trick and it shows the front of the engine needs to go up quite a bit. I just hope I don't run out of threads on the front mounts. I can't believe it was that far off and the coupler was never ruined. I also moved the gimbal bearing around with a mallet and that didn't work at all, probably because the alignment is so far off.
 
Shouldn't need to beat on it at all, a gimbal bearing is like an eye socket, it moves up/down and side/side. The tolerance is tight, so you need something smaller than the alignment tool to get the bearing lined up initially.
 
BillK2632 said:
Shouldn't need to beat on it at all, a gimbal bearing is like an eye socket, it moves up/down and side/side. The tolerance is tight, so you need something smaller than the alignment tool to get the bearing lined up initially.
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Luckily the weather is holding up here in CT, so I'll give it another try today. The photo gives you an idea of the amount it's off.
 

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Hard to tell from that pic, but the inner race on the bearing has to be parallel with the dowel. If it's not it can give the illusion that the motor needs to be moved a lot.
 
scoflaw said:
Hard to tell from that pic, but the inner race on the bearing has to be parallel with the dowel. If it's not it can give the illusion that the motor needs to be moved a lot.
Click to expand...
I hear what you are saying, but the coupler looked too high even without the bearing installed.

Anyway, good news. I was able to adjust it, and now am able to get the yoke in with two fingers, all but the last 1/2 inch. For that I had to use a rubber mallet to get it the rest of the way. Don't know why that last bit is a problem, but at least I know I'll easily be able to get the 6 nuts started on the outdrive. Here's the thing...... the front mounts were so out of adjustment I had to take them as far up as they could go. I almost ran out of threads, and will only be able to tighten the top nuts about half way. I'll use red loctite and keep my eye on them next season. I boat on a lake and only go about 1 1/2 miles when I take the boat out, so it's not as critical as it would have been for the previous owner. He used to regularly take it from home port on Long Beach Island on the Jersey shore, to Atlantic City. Now the 280 is in it's retirement on a lake in CT!
 
This would worry me long term.

The alignment being so far off as to require you to raise the mounts to the point that you’re out of threads and relying on Locktite would be a no go for me.

If it’s been that far out of alignment all along your coupler would be toast by now I would think, so something has changed.

Also, the alignment tool or the shaft should go all the way in with very little resistance. Drawing the drive on that last bit using the nuts is indicative of trouble heading your way as is having to force it off with a jack.

I’m not saying that drives always pop right off because they often don’t due to corroded shafts getting stuck in the gimbal bearing, which may have been the case with yours.

Good alignment should make removal and replacement easier with only the weight and awkwardness a problem.
 
Soulshine said:
This would worry me long term.

The alignment being so far off as to require you to raise the mounts to the point that you’re out of threads and relying on Locktite would be a no go for me.

If it’s been that far out of alignment all along your coupler would be toast by now I would think, so something has changed.

Also, the alignment tool or the shaft should go all the way in with very little resistance. Drawing the drive on that last bit using the nuts is indicative of trouble heading your way as is having to force it off with a jack.

I’m not saying that drives always pop right off because they often don’t due to corroded shafts getting stuck in the gimbal bearing, which may have been the case with yours.

Good alignment should make removal and replacement easier with only the weight and awkwardness a problem.
Click to expand...
Agree with this....you have a problem somewhere
 
It would be extreme but I’ve heard plenty of stories of bad stringers letting the mounts settle sending alignment way out. Your boat looks to be newer so hopefully that’s not the case, any indication of rot? Or maybe those vintage are composite stringers?
 
At this point I'm letting it rest until the Spring, at which time I'll decide which way to go. I think propping up the mounts with some 3/4" Starboard I have on hand would work nicely. 3/4" additional height would be perfect. From what I remember, the mounts are bolted to the hull with 2 bolts. I should be able to raise up the engine enough to get the mounts out, if I go that route.
 
It’s obviously too late now, but I wonder what the alignment looked like before the old gimble bearing was removed?

As far as the new bearing, make sure it is seated completely, properly and square in the bore.

As you can imagine, if the bearing is cock-eyed, it’ll throw everything out of wack.

I would even remove the new bearing and be sure there aren’t any obstructions to it sitting correctly before making such a drastic change to the mounts.
 
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