My ex-friend gave me a boat that has a 1979 Mercury 70 hp (blue) motor. I have been trying to get it to run properly for over a month now. I'll run down what has been done to date. Replaced...Stator, rectifier, plugs, rebuilt fuel pump, rebuilt water pump, cleaned both carbs and replaced floats and needle/seats, replaced fuel filter and installed a glass type in fuel line between pump and inlet, replaced all fuel hoses, new gas tank/primer bulb, repaired all corroded and damaged wires.
Motor runs well for 5-10 minutes then loses power. Goes from 30 mph to 8. Take home, clean carbs...take out and runs for 5-10 then bogs down. Found #2 plug isn't firing. Compression good...130 psi. Swapped #2 coil with #1 and won't fire. Have gone through troubleshooting guide for CDI switchbox and resistances are good. Yesterday, I purchased an in-line spark tester. Looked at each cylinder and they all looked the same...getting volts from coils. As a last ditch effort, I installed a new plug...still not firing. Don't know what to do next. If the #2 cylinder isn't getting fuel/lubricated, it would over heat and blow it up. If it's getting fuel and spark, it should fire...even if the timing is off, it should fire. Take the #2 plug out and it looks brand new with a little evidence of fuel on it.
I'm completely stumped!
Motor runs well for 5-10 minutes then loses power. Goes from 30 mph to 8. Take home, clean carbs...take out and runs for 5-10 then bogs down. Found #2 plug isn't firing. Compression good...130 psi. Swapped #2 coil with #1 and won't fire. Have gone through troubleshooting guide for CDI switchbox and resistances are good. Yesterday, I purchased an in-line spark tester. Looked at each cylinder and they all looked the same...getting volts from coils. As a last ditch effort, I installed a new plug...still not firing. Don't know what to do next. If the #2 cylinder isn't getting fuel/lubricated, it would over heat and blow it up. If it's getting fuel and spark, it should fire...even if the timing is off, it should fire. Take the #2 plug out and it looks brand new with a little evidence of fuel on it.
I'm completely stumped!
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