Motor mounts-gctid389055

[Guest]

So I have been a long time member that usually just uses the search function but I have come across a issue that I could use some help with. Don't hate me for a formula boat question! I come to you guys because I trust your input with the previous Bayliner restorations I have done! I have an addiction for restoring classic boats! Current project is a 1979 f20 formula with a 260 merc. Boat was stripped, no engine, wiring, ect. I have most of it done and now just installing fesh motor and drive but I cannot seem to get the alignment right to install the lower unit? The front motor mounts are as high as I can get them? Do they make different height motor mounts? Any help would be appreciated! If I don't get scalded for this first question regarding a formula I do have a couple more! And hopefully this boat will run for the first time in many years by this weekend!

[Guest]

Not sure on the motor mounts, but I have seen it where the stringers have been built up to gain more height.

[yachtman]

Depending on the type of mounts.....usually they are shimmed up with thin pieces of plywood. Make sure the staring point is in the middle of the mount adjustment. Dont leave it at bottom or top as you may need to adjust it down the road

Make sure the plywood is sealed with epoxy or polyester resin so it wont rot as 2859er said they can also ne built up with fiberglass especially if the change is excesive.

[Guest]

I have an '89 21.5" Ciera Sunbridge that I had trouble removing the outdrive from in 2008. Alignment check revealed the front of the engine was low. I ran out of adjustment trying to bring it in. I had to build up the front pillars to raise the mounts 1.5 inches. 3/4 inch would have been enough but as previously noted, it is nice to be in the middle of the adjsutment. The boat was probably this way for many years before i owned it. I pulled the OD again in 2011 and it easily slipped off and back on.

One boat builder told me that our flexable plastic boats are always moving and alignment should be checked everytime the OD is removed. Also make sure the boat is well and evenly supported on the trailer or blocks. Even then, the hull shape is probably different than when the boat is in the water.

[Chief_Alen]

I may not be the front mounts, could be the rear mounts. Could be the transom. Drive transom mount dropped, rot.

Just sayin.....

[2850Bounty]

The older Merc engine mounts are very similar, if not the same, as the Volvo Penta engine mounts.

Do yours look like these?





I agree with Dave. Often we'll see a shim underneath these.

Chief Allen may also be onto something.

There will be two fiber washers and hardware parts at the two rear engine mounts.

(i.e., where the flywheel cover mounting ears attach to the inner transom plate)



If these are not installed correctly, the geometry will be wrong, and no adjustment to the front engine mounts will make for a correct drive coupler alignment.

.

[Guest]

Sorry for the long delay...really long day at work...those ate the same mounts I have and I know there is no sag of any sort in the transom and I am positive the rear mounts have the correct fiber washers so I must be missing the wood shims under the mount. Anyone have a measerment of how thick it should be? I think I have some marine plywood that is 3/4 thick that I can make them out of. As always you guys are the ones to help a guy out no matter the make of boat. Thank you!

[yachtman]

The thickness should be what ever it takes to get the prpoer alaingment. If its excesive then adding more fiberglass might be in order. If i had to add say more than3/4 of an inch I might thnk about adding more glass.

[Guest]

Whoooo there.

Ok, let's get this straight....it it that:

1) You are trying to insert the alignment bar through the gimbal bearing and it won't engage the engine coupler?

or

2) You are able to get it to engage the coupler, but it's not getting to the point of alignment?

If #1, then it could just be that your gimbal bearing is not 'gimballed' into the right 'attitude'. Forgive me if you know this stuff already, but the gimbal moves like an eye in a socket so that it can pick up different angles. New ones are stiff, and don't like to move much. In it's 'just installed' position, it's extremely unlikely it will be at the correct angle to line up with the coupler. So, you have to slide your alignment bar into the gimbal until it butts up against the engine coupler and then bump the alignment bar firmly side to side and tip to bottom until it will engage the coupler. Once it's in, bump it a few more times to properly set the gimbal in the center of the coupler range. THEN you do the alignment, checking the grease marks etc and adjust the mounts for concentric-ness. If you move the mounts a lot, then repeat the alignment bar bump procedure to make sure the gimbal keeps up with the changes you're making.

If #2 then you are on the right track, but it's weird that it would be so far out that you would have to shim. Very hard to believe. I'd take it to a pro to align it, cause if you get it wrong, you'll blow up your coupler which suck the big one.

It should slide in with something like fingertip pressure.

Chay

[yachtman]

cfoss wrote:
Whoooo there.

Ok, let's get this straight....it it that:

1) You are trying to insert the alignment bar through the gimbal bearing and it won't engage the engine coupler?

or

2) You are able to get it to engage the coupler, but it's not getting to the point of alignment?

If #1, then it could just be that your gimbal bearing is not 'gimballed' into the right 'attitude'. Forgive me if you know this stuff already, but the gimbal moves like an eye in a socket so that it can pick up different angles. New ones are stiff, and don't like to move much. In it's 'just installed' position, it's extremely unlikely it will be at the correct angle to line up with the coupler. So, you have to slide your alignment bar into the gimbal until it butts up against the engine coupler and then bump the alignment bar firmly side to side and tip to bottom until it will engage the coupler. Once it's in, bump it a few more times to properly set the gimbal in the center of the coupler range. THEN you do the alignment, checking the grease marks etc and adjust the mounts for concentric-ness. If you move the mounts a lot, then repeat the alignment bar bump procedure to make sure the gimbal keeps up with the changes you're making.

If #2 then you are on the right track, but it's weird that it would be so far out that you would have to shim. Very hard to believe. I'd take it to a pro to align it, cause if you get it wrong, you'll blow up your coupler which suck the big one.

It should slide in with something like fingertip pressure.

Chay

It does seem odd that it was aligned but now it wont. How ever things do some times move and change. A second look might be a good idea.

[Guest]

I can get the alignment bar almost all the way in but it gets caught right before it goes into the motor? I can reach behind the engine and feel the alignment tool and by feeling around I can feel that there is more gap on top than on the bottom so that is telling me that the front of engine needs to go up? Correct? And drive will slide in almost all the way, maybe 3/4 of a inch gap before I could put the six nuts on the drive?

[2850Bounty]

The geometry between the universal joint section and the drive is not as critical as is the shaft alignment within the coupler splines.

This is why you are raising and lowering the front of the engine.

It also helps to understand that the Gimbal bearing can be made to oscillate within it's spherical retainer.

Suggestion:

Push the bar in until it contacts the drive coupler, and then pull it back just a bit.

Now swing the bar in an oscillating motion as though you are stirring something.

You should feel the Gimbal Bearing oscillate within it's retainer.

If the position is not just right, it can cause us think that the bar is not aligning with the drive coupler.

[Guest]

Thanks Rick, just went out and tried that...put tool to back of engine and came back half an inch and I cannot move any direction let alone circles did I do that right? Now setting myself up for jokes here but the tool I have is less than a foot long so maybe I don't have the leverage?

I can look in there with a flash light and it looks like it should go in??

[2850Bounty]

If you look closely here, you can see that the actual bearing and inner race are tilted within the outer retainer section.

This is the oscillation that I mentioned.

I don't know to what degree these articulate or oscillate, but they should move enough to allow for misalignment compensation.

It should also not require much force to get one to do this!

[Guest]

Then I must have one of two things happening here?

1. That is seized

Or

2. I now have the front of engine to high now

Grrr frustrating! I thought this was going to be the easy part!