F.L. Motor Mounts

[Pete Meisinger]

I'll try to post a picture but in case it does not work I will try a good description.

I want to align the engine on my Albin. I am not certain one of the mounts was tightened properly when we reinstalled the engine. The "up/Down" adjusters seem pretty straight forward but there does not appear to be any "Port/Starboard" adjustment screws or shafts or any of the numerous adjustment you can see on YouTube.

I suppose the mounts could be loosened from the stringers and the engine pry barred into correct alignment. The stringers are steel and in good condition. I have made some hardwood wedges in anticipation of the job to tap into position and hold the engine while I tighten the mounts.

But I don't like the idea. Am I missing something? Does anybody think I should change the mounts to some with horizontal adjusters?

pete

PS: Not having good luck with the images, I will submit this thread and work on pictures

 

[psneeld]

On my mounts the 2 holes where it is bolted down are different in one is a round hole the other is more of a slot.


That allows for a bit of movement.

 

[fractalphreak]

On my mounts the 2 holes where it is bolted down are different in one is a round hole the other is more of a slot.


That allows for a bit of movement.

+1 We just replaced our engine mounts this past year and have the same. One end is a slot, if you happen to still have that original design...

At first we were going with complicated efforts to rehoist/prybar/wedge engine for some side to side alignment. In the end i found it was actually easiest to just barely take the strain off with my lifting mechanism (readirod coupled to the engine lift points running through a hole in a 4x4 post laying across the salon floor) and physically pushing the engine... hard to find a pry point and it turns out you can push it around a bit..

 

[Nomad Willy]

I’ve always tapped mine left and right and never run out of adjustment range.
But that’s dependent on the original holes.

I’ve had Poly Flex mounts for about 13 years. Showing a bit of rust now but that dosn’t affect their usefulness. They aren’t rubber and that’s why I bought them. Rubber is not long lasting and dosn’t actually absorb vibration. The Poly Flex mounts have an active material that’s more like plastic. I think I see it used quite often on vibration dampeners. Not the white nylon but slightly transparent and in fruit-like colors.
If you drop a ball of rubber on a hard floor it bounces back up. There are flexible materials that don’t bounce back up. They just go “thonk” on the floor or bounce up only a small amount. You can hardly see my engine moving and nothing like an engine on soft Yanmar mounts.
The Poly Flex products are made in Australia.

 

[cdsailor]

Pete,

Did you replace the original mounts? If so, which mounts did you use on your Lehman 120? I'm thinking our engine mounts are past due for a change.

Thanks,
David

 

[Larry M]

Pete,

Did you replace the original mounts? If so, which mounts did you use on your Lehman 120? I'm thinking our engine mounts are past due for a change.

Thanks,
David

We replaced ours with OEMs (we have a FL SP135). We looked at other mounts but trying to find new style/modern engineered mounts that had the mounting holes and height adjustments as the old ones were impossible.

As it was we still had a minor issue. One of the mounting nuts was too thick and we had to replace it with a thinner one. We didn’t find out till all the new mounts were in place. We were able to raise the front of the engine off the mounts to put on thinner nuts with a 3’ 2x3” piece of maple. It’s amzing how much you can lift with a lever.

 

[Pete Meisinger]

I have not replaced or done the alignment yet. It will have to wait till Spring. I guess I don't see the need to replace them. I think the key is to get the tolerances right and then get the mounts good and tight. They were perfect before we pulled the engine for rebuild and probably perfect after the rebuild but I found two of the mounts were not all that tight and noted that the motor showed slight movement while underway.

pete

 

[cdsailor]

They were perfect before we pulled the engine for rebuild and probably perfect after the rebuild...

pete

Had they been replaced at any point prior?

I can’t imagine that our forty-year-old mounts are still working as designed, but I don’t have anything to compare them to. I know we have an annoying vibration at idle and low RPM that I’d like to get rid of.

 

[bogranjac1]

I’ve always tapped mine left and right and never run out of adjustment range.
But that’s dependent on the original holes.

I’ve had Poly Flex mounts for about 13 years. Showing a bit of rust now but that dosn’t affect their usefulness. They aren’t rubber and that’s why I bought them. Rubber is not long lasting and dosn’t actually absorb vibration. The Poly Flex mounts have an active material that’s more like plastic. I think I see it used quite often on vibration dampeners. Not the white nylon but slightly transparent and in fruit-like colors.
If you drop a ball of rubber on a hard floor it bounces back up. There are flexible materials that don’t bounce back up. They just go “thonk” on the floor or bounce up only a small amount. You can hardly see my engine moving and nothing like an engine on soft Yanmar mounts.
The Poly Flex products are made in Australia.

Hi NomadWilly,
Where you say 'nothing like an engine on soft Yanmar mounts' is that of the opinion as good/excellent/smooth or bad/non vibration absorbing ?
Reason I ask as I have Poly Flex and have been considering replacement with Yanmar mounts'
Regards Brett

 

[syjos]

I replaced the original FL mounts about 10 years ago with R & D mounts. They made a noticeable difference in vibration. Right after buying Sandpiper, I installed a 200 pound flywheel on the Lehman 120 to reduce vibration at low speed. It made a noticeable improvement at idle and slightly above but still not as smooth as desired. I'm not sure if new mounts was all I needed instead of the flywheel swap.

The rubber or whatever they used in the engine mounts can harden, loosen or deteriorate over time.

Modern mounts use superior materials and are designed and built to attenuate vibration more effectively. Selecting the correct motor mounts for the weight it supports is a critical aspect. And since the front and rear mounts rarely support the same weight, some math will be required. Google "Flexible engine mountings r and d" and there is a PDF brochure outlining the calculation procedure.

Or call PYI and they'll do the calculation for you.

Some boat manufacturers installed inproper mounts by not calculating the weight distribution of the engine/transmission correctly or not at all.

 

[mike50]

I replaced the original FL mounts about 10 years ago with R & D mounts. They made a noticeable difference in vibration. Right after buying Sandpiper, I installed a 200 pound flywheel on the Lehman 120 to reduce vibration at low speed. It made a noticeable improvement at idle and slightly above but still not as smooth as desired. I'm not sure if new mounts was all I needed instead of the flywheel swap.

The rubber or whatever they used in the engine mounts can harden, loosen or deteriorate over time.

Modern mounts use superior materials and are designed and built to attenuate vibration more effectively. Selecting the correct motor mounts for the weight it supports is a critical aspect. And since the front and rear mounts rarely support the same weight, some math will be required. Google "Flexible engine mountings r and d" and there is a PDF brochure outlining the calculation procedure.

Or call PYI and they'll do the calculation for you.

Some boat manufacturers installed inproper mounts by not calculating the weight distribution of the engine/transmission correctly or not at all.

Replaced all mounts on 2 DD 871’s with R&D mounts from PYI, followed the wt distribution specs and had a big reduction in vibration, and less noticeable noise.

 

[cdsailor]

I replaced the original FL mounts about 10 years ago with R & D mounts. They made a noticeable difference in vibration. Right after buying Sandpiper, I installed a 200 pound flywheel on the Lehman 120 to reduce vibration at low speed. It made a noticeable improvement at idle and slightly above but still not as smooth as desired. I'm not sure if new mounts was all I needed instead of the flywheel swap.

The rubber or whatever they used in the engine mounts can harden, loosen or deteriorate over time.

Modern mounts use superior materials and are designed and built to attenuate vibration more effectively. Selecting the correct motor mounts for the weight it supports is a critical aspect. And since the front and rear mounts rarely support the same weight, some math will be required. Google "Flexible engine mountings r and d" and there is a PDF brochure outlining the calculation procedure.

Or call PYI and they'll do the calculation for you.

Some boat manufacturers installed inproper mounts by not calculating the weight distribution of the engine/transmission correctly or not at all.

Informative response and a good lead. Thank you.