Cutlass bearing sizes

[PhillipPalacios]

Hello all,
When we hauled out I completely missed my checklist to check the cutlass bearing- last know to be installed 2016 by previous owner when they re-powered the boat with a Volvo Penta d3-110.
Boat is on the hard in Aruba at Varadero Marine and I am in the states until end of hurricane season so I can’t easily check the bearing and Aruba doesn’t have the parts availability of some other islands like Sint Maarten.
My plan is to source it now and carry it to the boat when I arrive sometime in October or November. However, the previous owners have conflicting information about the size of the bearing.
On some documentation it calls for a 35mm x1 7/8 bearing and the only version of this I can find is available in the eu-vetus marine. North American or Caribbean suppliers don’t seem to have this size available- Johnson durax does not list this as a part they make either.
The owner’s documents list a few different part numbers from budget and island water world. The part number from budget corresponds to a 1 3/8 x 1 7/8 bearing. This IS available through US and Caribbean suppliers and as a part available from Johnson duramax.
Now the shaft is listed as a 35mm shaft in all the other documentation, so the question I have is with the available 1 3/8 x 1 7/8 bearing.
If my conversion is correct it is technically.07mm to small for the shaft.
What is the proper course of action? Is this with normal tolerances?
I’m not interested in just getting it working- I want it to be right so that it will work after 10 hours, 20 hours, 100 hours etc.
I have time so that I could order a bearing from the eu. I could also get the one available in the US-
I mostly don’t want to end up in October discovering that the bearing is shot and not being able to launch in a reasonable amount of time because a part has to be sourced from Europe.
Thanks!
Phillip

PS this is the info from the previous owners notes:
“870354132
35mm x 1.87
Cutlass Bearing Johnson Duramax – 35mm x 1 7/8 BUDGET Code CB/BM35X178

Island Water World AB351781
Cutlass bearing 303402“

[dwg2116]

35 mm is less than 3 thousands of an inch bigger than 1 3/8. I'll bet the manufacturing specs of a rubber bearing are not even within that tolerance.

I would use the 1 3/8 in a heartbeat, and not think twice about it. In fact get a spare while you are at it, so you are never in this dilemma again.

However, for peace of mind, Call Johnson Duramax, and see what they say.
PHONE +1 440.834.5400

[SailingHarmonie]

A dufor surely has a 35mm shaft. Not an 1 3/8" shaft.

I have my opinion, (get the RIGHT SIZE) but if that was an insurmountable problem, if I was you I'd talk to the manufacturer about allowed tolerances and not take any internet advice about it.

Because, why not????

FYI: https://www.ebay.com/itm/324748019550

[PhillipPalacios]

Originally Posted by SailingHarmonie

A dufor surely has a 35mm shaft. Not an 1 3/8" shaft.

I have my opinion, (get the RIGHT SIZE) but if that was an insurmountable problem, if I was you I'd talk to the manufacturer about allowed tolerances and not take any internet advice about it.

Because, why not????

FYI: https://www.ebay.com/itm/324748019550

Yes. Like I posted above the shaft is 35mm.
The link to eBay say 35mm in the title but the item description is the 1 3/8” dimension as is the actual part number from Johnson Duramax. Who I have emails out to.
The complication is the repower- I’m not 100% sure what was changed and what was left “stock”
The original diesel from what I can tell was not a Volvo Penta - so what else changed? Only the previous owners will know.

Asking on an Internet forum is not the be all end all, but is a logical and valid source to seek information from others who also may have eu built boats in the Caribbean needing cutless bearings.
I mean it’s kind of the point of the forum isn’t it?

[PhillipPalacios]

Originally Posted by dwg2116

35 mm is less than 3 thousands of an inch bigger than 1 3/8. I'll bet the manufacturing specs of a rubber bearing are not even within that tolerance.

I would use the 1 3/8 in a heartbeat, and not think twice about it. In fact get a spare while you are at it, so you are never in this dilemma again.

However, for peace of mind, Call Johnson Duramax, and see what they say.
PHONE +1 440.834.5400

Thanks for the input- I have an email out to them- will probably follow up with a phone call.

[HeywoodJ]

Originally Posted by SailingHarmonie

A dufor surely has a 35mm shaft. Not an 1 3/8" shaft....

If it surely has a 35mm shaft then it surely has a metric 50mm strut/bearing housing. That, I think, is the OP's problem. For a 35mm shaft the bog standard bearing has a 50mm OD. 1 7/8" is only 47.6mm. So, if the housing is truly 1 7/8" then you are probably stuck with a 1 3/8" bearing. The difference on that side is tiny, and if the shaft is of any age it has probably worn that much anyway and 1 3/8" (34.9mm) will be a perfect fit.

Quite frankly, I would be much more concerned about the fit in the strut. Did the PO use a sloppy fit 1 7/8" in a 50mm housing? Did they shim it somehow? Or is your boat truly that odd duck with a metric shaft and an imperial strut/housing?

I'd say get the 35x50 and then you could have any machine shop on the island turn it down if you truly need 48mm, but Johnson's shell is only 3mm thick, turning more than a mm off that won't leave much meat for installation.

[PhillipPalacios]

Originally Posted by HeywoodJ

If it surely has a 35mm shaft then it surely has a metric 50mm strut/bearing housing. That, I think, is the OP's problem. For a 35mm shaft the bog standard bearing has a 50mm OD. 1 7/8" is only 47.6mm. So, if the housing is truly 1 7/8" then you are probably stuck with a 1 3/8" bearing. The difference on that side is tiny, and if the shaft is of any age it has probably worn that much anyway and 1 3/8" (34.9mm) will be a perfect fit.

Quite frankly, I would be much more concerned about the fit in the strut. Did the PO use a sloppy fit 1 7/8" in a 50mm housing? Did they shim it somehow? Or is your boat truly that odd duck with a metric shaft and an imperial strut/housing?

I'd say get the 35x50 and then you could have any machine shop on the island turn it down if you truly need 48mm, but Johnson's shell is only 3mm thick, turning more than a mm off that won't leave much meat for installation.

All good points.
I didnt do the conversion for the other side of the dimension- I was totally focused on the shaft size and not the tube size. lol- ANOTHER variable.

Thankfully none of these break the bank- so I may end up just carrying two or three sizes with me to the boat, annoying, but I'd rather be prepared.

The PO was fairly meticulous on this boat - I keep digging into various nooks and crannies and seeing care and attention, so I cannot imagine them "making it work" although perhaps someone at the yard did their cutlass for them in a less than scrupulous manner. idk.
I do know we plan on putting on more bluewater miles with her this next season so I want it to be properly done.

I did hear back from Johnson Duramax - they have said they do not and have not manufactured a 35mm x 1 7/8" bearing, and if I truly need that size they referred me to a local marine machinist shop.

So- the mystery is still there. The part number doesn't match the PO's description, and the likelihood that they are mistaken seems to be growing. Actually, whatever way this turns out part of what they have written down was mistaken.
But that doesn't help in the here and now.
I'll keep everyone posted once I'm there in a couple months