myoldboat2
Petty Officer 1st Class
- Joined
- Jun 3, 2007
- Messages
- 303
1974 Mercruiser 140 engine s/n 388xxxx
Mercruiser "Late Model I" Stern Drive s/n 390xxxx
I'm curious about this...
The manual for my engine is Mercruiser Service Manual Number 2. Under "models covered in this manual" it includes "Mercruiser Stern Drive Engines", "MCM 140 s/n 3771645 - 4918569", so that's me. On page 8A-1 the firing order for Model 140 refers to Figure 1. Here is that figure (the parts in black):
But my plug wires connect as I've numbered in red. Why? I have a Pertronix electronic conversion (no points any more). My timing is set per the spec (I set it a few years ago).
I'm not familiar with indexing a distributor... Does the indexing get set when the distributor is mounted on the engine? Did I probably end up with a replaced distributor (but why would that change the index)? Is the manual wrong?
My engine runs fine at idle, cruise and WOT. There's no way it's firing each cylinder 90 degrees too late.
Mercruiser "Late Model I" Stern Drive s/n 390xxxx
I'm curious about this...
The manual for my engine is Mercruiser Service Manual Number 2. Under "models covered in this manual" it includes "Mercruiser Stern Drive Engines", "MCM 140 s/n 3771645 - 4918569", so that's me. On page 8A-1 the firing order for Model 140 refers to Figure 1. Here is that figure (the parts in black):

But my plug wires connect as I've numbered in red. Why? I have a Pertronix electronic conversion (no points any more). My timing is set per the spec (I set it a few years ago).
I'm not familiar with indexing a distributor... Does the indexing get set when the distributor is mounted on the engine? Did I probably end up with a replaced distributor (but why would that change the index)? Is the manual wrong?
My engine runs fine at idle, cruise and WOT. There's no way it's firing each cylinder 90 degrees too late.