'68 55hp Chrysler Lower Gear Oil/Spark Plug Questions

[robrileyw]

I was wondering what lower gear unit oil these old Chryslers prefer? I've seen Quiksilver around, Supertech from wally world which I probably wouldn't buy, Lubrimatic from Gander Mountain? Just wondering what other people have successfully used. I've had the boat for about two years and haven't changed it once, just stored it for winter, so I'll be doing it this spring.
Also, as far as spark plugs go...I know to use the L82C's on this engine, but was wondering what the correct gap I should set these plugs at that would help the old chrysler run smoother...I'm pretty sure they come pre gapped at .02 but i read somewhere that you should have the plugs gapped to .03 or .04?? Another issue that I've read somewhere is not gapping these plugs or you can melt a hole in the middle of the piston? Someone please clarify....

 

[Frank Acampora]

Re: '68 55hp Chrysler Lower Gear Oil/Spark Plug Questions

Those old Chryslers are set up rather loose and the teeth are almost straight. They are remarkably not fussy and almost any lower unit oil or even auto rear end oil will do. The Wal-Mart brand is a name brand oil and you should not be worried about saving a buck or two. I use Supertech all the time. I was using Lubri-Matic synthetic because Wal-Mart had a close-out of 1 buck per quart--so I bought all they had on the shelf.

As far as plug gap, if your engine has battery or magneto ignition, set the gap to .030 or .035--you can't go wrong. You can try .040 and if you have no problems, leave it there.

You misread the posts. It is not failure to gap plugs that causes piston damage. It is the use of a gapped bent eletrode plug in an electronic ignition designed for surface gap plugs that will or may cause piston damage.

 

[robrileyw]

Re: '68 55hp Chrysler Lower Gear Oil/Spark Plug Questions

Ok, thanks a bunch, I appreciate it.