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AQ125A engine removal?

J

JRB

New member
I'm new here. Just got my first boat. '85 Bayliner bow rider with Volvo Penta AQ125a on a 270 stern drive. Got motor started today after a new fuel pump, carb rebuild and fixing plug wires being plugged in the wrong places on the cap! Runs strong but has a REALLY bad vibration that will suddenly go away at about 2800 rpm. Sounds scary, like flywheel bolts are loose or something! I need to investigate, but have no idea how motor comes away from stern drive unit. Do I unbolt motor from bell housing? Do I have to pull stern drive unit from outsider the transom first? Never done a boat before. Only cars till now. Help!

-JB
 
I would remove the upper unit from the drive and inspect the u-joints first. It would be better to remove the engine from the bell housing. In the bell housing is the intermediate shaft. The bearings on this shaft will probably need to be changed. You can get them at a good bearing supplier, not through the VP dealer, there price is ridiculous.
 
JB, very likely the PDS bearing is gone. This will be the single bearing on what's called the Primary Drive Shaft.
The PDS is inside of the Flywheel Cover (aka bell housing in the auto world).

NOTE: In the thread that Chris linked us to, the Volvo Penta exploded view shows the V-8 "double bearing" PDS.
The double bearing PDS will not remove from AFT without engine removal.
Yours will be a single bearing PDS...... (baring no rust or corrosion issues) these can be removed from AFT without engine removal.
So basically, there is no reason to remove the engine for PDS bearing replacement on the OHC 4's.

Drain out drive oil, tilt helmet up, loosen bellows clamp, remove drive transmission ONLY.... and watch carefully for the shims underneath the transmission.
These must all go back in!

Go here and read up on PDS removal in one of the links via Volvo Penta AQ series frequent Q's & A's by myself, or Volvo AQ Drive and PDS Bearing Info by rkcarguy.
Pay particular attention to the modified extra long needle nose pliers that you will need in order to remove the large snap rings.
This should walk you through the steps necessary to replace this bearing.

NOTE: to the best of my knowledge, there is no manufactured snap ring pliers that work as well, or as easily, as a modified extra long needle nose pliers.
The cavity is just too deep for any regular snap ring pliers to work.
Just gently round the tips, tweak them inward slightly so that they will not slip out of the snap ring eyelets!
images



For your OHC 4, this is a single standard Koyo or SKF 6206 bearing that can be purchased from a bearing supplier (save yourself some money).
NO Chinese bearings!
BBQ'd Pork and Fried Rice.... yes, but no bearings from China!

Your PDS will look like this, but will very likely sport fine splines for the female drive shaft yoke (course spline being shown here).

attachment.php



But if for some reason you do pull the engine, best to separate the engine from the F/C and lift it out.
Your engine is likely cantilever hung...., which means no front engine mounts.


If you have trouble, post back.


BTW, in 1985, you likely have a 275.... not a 270.

.
 
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Rick and Chris,

Thanks so much. Very helpful advice. Today I will remove drive transmission and investigate. I suspect it is the the PDS bearing, judging by how deathly horrible the vibration was and how it would suddenly "smack" quiet at higher rpm. Lets see what I find...I will let you know. I got this boat and trailer for $400 and so far have found no major expensive issues. Floor and stringers were starting to rot as well as some ply in bow and either side of engine. Was easy to chop and cut out and replace and glass in. I want to make sure the engine and outdrive are running sweet before I glass in the new plywood around the rear. Lots of room right now with all that out of the way. And yes, no Chinese bearings please!

-JB
 
OK guys, update:
I pulled the transmission from the top of the drive and noticed a few things:

1. Bellows had about half a cup of oil in it. Appeared to be drive oil. Input shaft seal of transmission?

2. PDS appears firm. i.e. No radial play. Started and ran engine with trans removed and vibration is gone.

3. The two u-joints in the CV joint appear too loose. Meaning I get axial play of about 1 mm both ways in each cross. No radial play apparent so seems needle bearings are OK. But it seems that I would want to press the cups in tighter. Don't see that I can do that though as they seem to be held in a fixed position by circlips.

CONCLUSION:
From the above I would say that the source of my vibration was primarily from the U-joints axial play. Note that I was running tho motor with the out drive tilted all the way up. perhaps that was the first no-no?

But now I have manually wound down the tilt mechanism (I will have to get the tilt motor and control box operating - next project) in order to pull transmission.

I think I will replace the PDS bearing and rear seal, u-joints and trans input shaft seal.

You already advised a bearing house for the PDS bearing. I imagine I can also get it's attendant seal and the trans seal from same place?

How about the U-joints? Where can I get those for a fair price rather than VP?

Any other suggestions while I have it this far apart?

-JB
 
JB, see my text in blue font.
JRB said:
OK guys, update:
I pulled the transmission from the top of the drive and noticed a few things:

1. Bellows had about half a cup of oil in it. Appeared to be drive oil. Input shaft seal of transmission?
Yes.... there is a main drive gear seal here.
There are definitely some Do's/"Don'ts pertaining to accessing this area on your particular transmission.
Yours will use the all steel bearing box, which means that the clamping collar bolts are wet area bolts... which can equate to thread corrosion.


2. PDS appears firm. i.e. No radial play. Started and ran engine with trans removed and vibration is gone.
In the twenty plus years that I've been doing these drives, I know of no method for determining if the PDS bearings are good.
I can tell you if one is bad.
Best method is to remove the PDS... and by then you may as well replace this $14 bearing.
Shot in the foot, if not!


3. The two u-joints in the CV joint appear too loose. Meaning I get axial play of about 1 mm both ways in each cross. No radial play apparent so seems needle bearings are OK. But it seems that I would want to press the cups in tighter. Don't see that I can do that though as they seem to be held in a fixed position by circlips.
On your transmission, and if no one has replaced this with a later style, the bearing crosses (aka U-joints in farm language :D) are a Spicer 5-1306X, and cost approx $14 each.
This is another "shot in the foot" if we don't replace them, IMO.


CONCLUSION:
From the above I would say that the source of my vibration was primarily from the U-joints axial play.
Note that I was running tho motor with the out drive tilted all the way up. perhaps that was the first no-no?
A definite NO NO!

But now I have manually wound down the tilt mechanism (I will have to get the tilt motor and control box operating - next project) in order to pull transmission.

I think I will replace the PDS bearing and rear seal, u-joints and trans input shaft seal.
Again, in order to access this main drive seal, best read some links that I can provide for you.
The issue (in part) will be the four Bearing Box clamping collar bolts, and success at removing them without damage.
I could tell you story after story about some of the transmissions that I receive "After the Fact" when the wrong procedure has been used.

You already advised a bearing house for the PDS bearing. I imagine I can also get it's attendant seal and the trans seal from same place?
Yes... the bearing is a commonly used bearing, but the seals often have to be ordered.

How about the U-joints? Where can I get those for a fair price rather than VP?
See above.
A good 4WD or Off Road shop will usually have these in the Spicer.

Any other suggestions while I have it this far apart?
Upper pivot tube bushing and water neck fitting with special beaded gasket.
The bushing R&R is rather involved, and requires that the lower unit also be removed.
If no play/slop... it may be OK.
If bad.... if will affect the water neck's sealing ability.

-JB
Click to expand...
 
Thanks Rick. Superb help you are providing. I will replace the PDS bearing and seal. Also the trans mainshaft seal.

And, of course, the bearing crosses.

Can you give me the link(s) you refer to to help me through the mainshaft seal access?

I'm having fun. So far, looks like I got a good deal!

And I will inspect the other points you mention.
 
Hi Rick.

Productive day. Got the clamping collar bolts out without any issue. I now have the following parts removed and awaiting their replacements:

1. PDS bearing.
2. PDS aft seal.
3. Bearing crosses.
4. Water neck and gasket.
5. Drive and exhaust bellows.
6. Transmission mainshaft seal.

I've got the entire outdrive off and on a bench. I was very careful to retain all shims in the transmission disassembly as I don't want to have to mess with the gear mesh and bearing loading. Few more questions though:

A. I intend on replacing the trans mainshaft seal only and re use the washer that rides inside it in order to not change any tolerances. The washer appears in good shape. Any problem with doing that?

B. I have yet to remove the upper pivot tube bushing. Haven't figured out how to get the tube inside it out and then get the yoke, or whatever you call it, off so that I can press out the bushing. One of the links in the link you gave me is dead and I am having trouble figuring this one out. I would love to get a PDF of the OEM repair manual that covers the 275 but haven't found one yet.

C. There are a number of o-rings here and there as I go and I wonder if there are kits available for all this. If you could recommend a good priced on-line supplier for these bits and pieces, my drive and exhaust bellows, water neck and gasket, etc. I would really appreciate it. I am brand new to the boat world and do not have all my sources and suppliers figured out.
 
JB, see my responce is blue text.
JRB said:
Hi Rick.

Productive day. Got the clamping collar bolts out without any issue. I now have the following parts removed and awaiting their replacements:

1. PDS bearing.
2. PDS aft seal.
3. Bearing crosses.
4. Water neck and gasket.
5. Drive and exhaust bellows.
6. Transmission mainshaft seal.
Do not forget to replace the Bearing Box O-rings, the eccentric piston double lip seal and the shift mechanism housing O-ring, the top cover gasket, fill plug gasket, and the hollow bolt O-ring.
None of these gaskets or O-rings can go second time around.

I've got the entire outdrive off and on a bench. I was very careful to retain all shims in the transmission disassembly as I don't want to have to mess with the gear mesh and bearing loading. Few more questions though:

A. I intend on replacing the trans mainshaft seal only and re use the washer that rides inside it in order to not change any tolerances. The washer appears in good shape. Any problem with doing that?
No... in fact I'd encourage you to use it if the seal surface is OK.... watch for and inventory the small shims.
If not good, we can polish .003" -.004" from this without any harm.
Be sure to replace the tiny O-ring on the FWD side towards the male yoke.

B. I have yet to remove the upper pivot tube bushing. Haven't figured out how to get the tube inside it out and then get the yoke, or whatever you call it, off so that I can press out the bushing. One of the links in the link you gave me is dead and I am having trouble figuring this one out. I would love to get a PDF of the OEM repair manual that covers the 275 but haven't found one yet.
The "pivot tube" can be carefully pressed out downward.
Mildly heat the aluminum Intermediate housing if need be.
Caution: This is a soft tube, and either end is critical ... upper end for the beaded gasket.... lower end for the fat O-ring seal.


C. There are a number of o-rings here and there as I go and I wonder if there are kits available for all this. If you could recommend a good priced on-line supplier for these bits and pieces, my drive and exhaust bellows, water neck and gasket, etc. I would really appreciate it. I am brand new to the boat world and do not have all my sources and suppliers figured out.
Use the OEM or Sierra kit only if you are replacing every thing.
Otherwise, purchase the parts individually.
Your call!
Click to expand...
 
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Thanks Rick.

Got the pivot tube out. I hadn't split the intermediate from the lower drive yet. Did that and got it all apart. Ordered all the seals, bellows, bearings, crosses, bushings and o-rings I will need to reassemble. Total cost for everything was about 180 bucks. That will give me a sound outdrive unit.

So far so good!

Your help and advice is invaluable!

But yet another question:

Looking with a flashlight into the back of the flywheel fever, I see a ball bearing in the center of the flywheel or damper that the forward end of the PDS piloted into. It looks sort of clean and dry. Should I worry about this? Seems to me it wouldn't ever spin as the PDS is splined into the flywheel/damper.

-JB
 
JRB said:
Thanks Rick.

Got the pivot tube out.

Looking with a flashlight into the back of the flywheel fever, I see a ball bearing in the center of the flywheel or damper that the forward end of the PDS piloted into.
It looks sort of clean and dry. Should I worry about this? Seems to me it wouldn't ever spin as the PDS is splined into the flywheel/damper.

-JB
Click to expand...
Good on the pivot tube. These can be difficult to remove.... sounds like you didn't have any problems.


As for the crankshaft bearing.... this is a carry-over from the auto side.
You are correct.... there is no rotational difference between the crankshaft and PDS.
The bearing is used as a "centering" device only.
Just grease the pilot nose and the Borg Warner splines upon re-assembly.
You'll be just fine.

Side note:
Regarding the lower pivot tube O-ring, I generally glue this O-ring into the bore where it rests.
Weather Strip adhesive, or _____ works just fine.
I do this so that it will not move during assembly.

The upper plastic bushing just dry fits into the main suspension fork.

Look carefully at the needle bearing surface of the pivot tube.
If bad, you may want to replace both needle cage and pivot tube.
Pay close attention to the grease port.... the needle cage must remain below this port.... up just high enough to allow the lower seal to be installed.

.
 
Rick,

Thanks a lot. Looks like I am set then. Just need to wait now for the parts to arrive. Meanwhile, I will get the tilt motor working and get the alternator to charge and clean up the engine a bit. I will let you kn
 
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