Re: 1970 Mercury 135hp rotor change out??
Be very, very careful when removing the rotor; if you damage the pickup (what senses off the copper 'chopper' disc), you'll also have to replace the very expensive distributor housing. Don't tap, pry, or otherwise use any kind of force on the pickup.
This means that when tapping the old rotor/dist shaft out the bottom of the distributor housing, hold on to that chopper disc so it can't move. The dist has a tab which 'keys' into the rotor shaft, and usually it'll be rusted to the shaft. Tap the top of the dist shaft carefully while holding onto that chopper disc so only the rotor moves.
With the rotor removed, you'll note a snap ring holding in the bottom bearing for the dist shaft. Check this bearing carefully and renew as required. Also renew the top bearing as it'll most likely be bad. Replace the snap ring, they tend to get brittle from heat/rust and will break, sending shrapnel into the rotating parts.
I lost the dist on the 1350 I had on a SS 16' Sidewinder, years ago. The snap ring broke and tore up the trigger. Luckily the local outboard 'boneyard' had a good used dist for $50, a few hours work and I was back on the water. They don't sell that cheaply anymore!!!!
A few tips for getting the dist apart:
If I recall the dist bolts (3 ea) on a 1350 are thru-bolts with nuts at the bottom. Newer models have blind mounting holes threaded in the dist and you must remove the flywheel to gain access to one of the bolts.
Remove the dist pulley cover bolt (5/16" head) and the dist cover comes off.
Before removing the dist drive belt, find the cast-in arrow on one of the ribs in the dist pulley. Turn the flywheel until this arrow points directly in-line with the centerline of the crankshaft. You'll then note what flywheel timing marks are being pointed to by the arrow.
To get the correct belt timing, be sure to reassemble with the arrow pointing the same way.
Carefully slip the belt off the dist pulley, you can work it off with your fingers. It's not recommended to use prying tools, so as to avoid damage to the belt.
With the belt moved inwards & away from the pulley, use a couple of flat-bladed screwdrivers, 180 deg from each other, to pry up the pulley.
It should come easily, don't use a lot of force as you can break the outer edges of the pulley. If it's reluctant, use some penetrant like PB Blaster, Kroil, or a 50/50 mixture of acetone and ATF (better even than Kroil!). Let it soak for a few hours or come back the next day and the pulley should pop right off.
To gain access to all (3) of the dist mounting nuts, remove the front bracket which holds the idle stop/carb stop/spark advance screws. With the nuts removed, pull the distributor down and out.
The cap at the top of the dist is threaded, with internal lock tabs. Pry those tabs inwards and unscrew the cap (regular, right-handed threads).
With the cap removed, you can pry out the top bearing. Use (2) very small 'tweaker' screwdrivers or similar tool thru the holes in the side of the dist. Try to angle the tools so they pry on the outer race of the bearing, rather than in the middle, where you could damage the bearing. Just in case it's still good.
With the bearing out, the last thing to do to free the rotor is to remove the dist shaft retaining nut. A 3/4" deep socket works best for this.
Since the rotor is busted, just clamp the dist shaft in a vise or grap with Vice Grips. The nut also has right-handed threads. Once this nut and the tubular spacer underneath is removed, the rotor is free to be driven out the bottom as previously described.
Just treat the trigger pickup with kid gloves and you'll be fine!
If the lower bearing is bad, pull the snap ring and drive the bearing out from the top. It's a press-fit into the dist housing, be sure to press on the outer race only when installing.
The rest of the reassembly is a cinch, it all goes back together a lot easier than it comes apart!
Hopefully that'll get you thru the job, if there's anything I left out be sure to ask.
HTH........ed
