josewhales
New member
Hello everyone,
I am a newbie on this forum and I would greatly appreciate any help from all you knowledgeable folks! I have learned quite a bit from all of you as a guest in the past and I am struggling to get an old Merc. 7.5 out on the water.
My situation: My 7.5 will not start unless it is in gear and at 3/4 throttle. After starting, the engine will not idle and stalls once the throttle is returned to the "shift" position.
Engine history: I purchased the engine recently for $50 bucks at a garage sale. Seller was asking $200 but couldn't run it due to no fuel tank so he dropped the price. He told me it had belonged to his deceased father and had been sitting for 3 years. It is very clean so I took a chance. When I got it home, it would only start in gear at 3/4 throttle.
What I have done so far:
1. Seafoamed carb and replaced plugs.
2. Disassembled carb to inspect and clean (appeared to be clean to begin with).
3. Checked float adjustment, good.
4. Replaced old fuel lines.
5. Checked spark. Spark is weak on top cylinder and only at 3/4 throttle. Spark is very intermittent and only at 3/4 throttle on lower cylinder.
6. Visually inspected coils for cracks, burns (none). Inspected high tension leads for arcing (none). Swapped leads between coils, no difference.
7. Cleaned and re-tightened wires going to coils.
8. Inspected points, showing their age but not burnt and still opening and closing.
9. Visually inspected stater, no burned wires or marks.
I have ordered a manual but it will not be here for a few days. I am wondering if someone can help me properly diagnose the ignition system or if they have run across this exact situation in the past.
Thanks!
I am a newbie on this forum and I would greatly appreciate any help from all you knowledgeable folks! I have learned quite a bit from all of you as a guest in the past and I am struggling to get an old Merc. 7.5 out on the water.
My situation: My 7.5 will not start unless it is in gear and at 3/4 throttle. After starting, the engine will not idle and stalls once the throttle is returned to the "shift" position.
Engine history: I purchased the engine recently for $50 bucks at a garage sale. Seller was asking $200 but couldn't run it due to no fuel tank so he dropped the price. He told me it had belonged to his deceased father and had been sitting for 3 years. It is very clean so I took a chance. When I got it home, it would only start in gear at 3/4 throttle.
What I have done so far:
1. Seafoamed carb and replaced plugs.
2. Disassembled carb to inspect and clean (appeared to be clean to begin with).
3. Checked float adjustment, good.
4. Replaced old fuel lines.
5. Checked spark. Spark is weak on top cylinder and only at 3/4 throttle. Spark is very intermittent and only at 3/4 throttle on lower cylinder.
6. Visually inspected coils for cracks, burns (none). Inspected high tension leads for arcing (none). Swapped leads between coils, no difference.
7. Cleaned and re-tightened wires going to coils.
8. Inspected points, showing their age but not burnt and still opening and closing.
9. Visually inspected stater, no burned wires or marks.
I have ordered a manual but it will not be here for a few days. I am wondering if someone can help me properly diagnose the ignition system or if they have run across this exact situation in the past.
Thanks!