Lower bearing end float and bearing shim

[jelly9]

Hi all,

I have Mercury 2 stroke 60hp SN: 9596063 which was on project boat i just brought.
I had to replace a piston which is no big issue, but when i removed the crank and removed the end bearing to replace them there was no bearing shim, item 3 in the below image.
So i will buy a pack of new shims, but the problem is there no info on how to setup the shim / end float? in to 2 manuals i have for the engine.

i've work on a lot bike a car engine but i'm new to outboards, as this engine has 2 deep groove bearing top and bottom and no tapered bearing to add pre load there will all way be end float, so is the shim there for some other reason like to just allow for the radius on crank shaft and to allow the bearing to take the load in a flat face and not on radius.

Can anyone point in the right direction please.
Thanks in advance.

 

[flyingscott]

A factory manual should tell you that.

 

[racerone]

If there was no shim , then you do not need to install any shim.

 

[Faztbullet]

The shim/s are used to adjust crankshaft end play or "float" as I like to call it. Due to casting and machining some blocks will need several and some none. As Racer stated if it didn't have any it doesnt need any unless it was previously disassembled. What made piston go bad?

 

[jelly9]

Hi,
it was a non running when i got the boat with not history or at least the sale said he had never had it running and didn't know it started. it did turn over by hand ok.

As i looked in to it i found the coil for the top cylinder didn't work, did a compression check and top cylinder had almost nothing.
after removing the side cover i could see the top piston had a broken a piston ring.
i stripped the engine and there was damage to the ring groves and some damage to the top of the piston as well, there is some small mark at the top of the cylinder but nothing to worry about.
parts of the broken ring were in the the top of the piston but no in the top of the cylinder.

it doesn't look like it been apart, it got the older style 3 ring pistons in it. but you never know it could have been apart before i suppose.

does the above point to anything to do with the missing shim?

 

[racerone]

Not at all.-----If no shim was needed on original assembly , then no shim will be needed today.

 

[Faztbullet]

Top piston damage on these our usually water cooling related or ignition problem. Make sure you replace impeller and switchbox (OEM)

 

[jelly9]

Thanks, the top coil pack did not seem to be working, but i didn't check the switchbox i will keep a eye on this when it's rebuild. Unless there is a way of checking the switchbox off the engine? The impeller looks new may this was changed after the damage was done.