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    Intermittent "cough" during startup.

    Testing tied to the dock can easily simulate idling tied to the dock. In my case tied to the dock it can simulate from idle to WOT as I have a Sport jet and the RPM seems the same underway or TTTD. Actually they suggest idle be final adjusted with the boat being allowed to move and someone else...
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    1994 Force Mercury 120hp No spark

    Look under that little shelf below the key switch. Often the kill switch is a small toggle switch that is hooded so that a ring to the lanyard is trapped when the switch is up and the kill switch is letting the engine run. When the lanyard is pulled the ring flips the switch and kills the...
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    significance of same cylinder-pressure

    You are measuring pressures from idle with no ignition. There is vastly higher pressure when running. By the way the three cylinder has stock a different reading . From the service manual: NOTE On 90 hp models, compression on the No. 1 cylinder is normally 5-10psi (34.5- 69.0 kPa) less than the...
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    No spark 90 hp 1999 Force after switchbox replacement

    AKA Bullet connector. They (loosely) connect electrical wires. They get dirty, have bad connection, get hot and lose their connection tension. The heat turns the vinyl protective cover black. Cleaning them and slightly squeezing the female side can sometimes help make a good connection. The...
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    Corrosion Removal and Repainting My 1990 Force 90

    These days real zinc chromate is hard to come by. An epoxy primer and a top c.oat would be about the best you could do. For rattle can I have used black epoxy appliance paint. The primer attaches to the metal, but should be protected by the top coat. If you are really serious two part epoxy is...
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    No spark 90 hp 1999 Force after switchbox replacement

    Will it run now with the regulator disconnected? Check for spark as there might be another problem. Also sometimes one or more magnets come loose and would give a scraping sound as the motor is turned (plugs out by hand). Also check for spark whole the plugs are out as the engine will turn...
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    Force 75 threw a magnet at us

    Too bad you did not need a flywheel while I had a new style I was trying to fit on an early engine. No one wanted it and I sold it cheap on eBay. Water under the bridge... If swapping the coils made no difference and each cylinder has good spark then I and the compression is equal and good on...
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    Force 75 threw a magnet at us

    The tach will operate from either the gray wire from the rectifier/regulator or tapped directly off one one of the yellow wires from the coil. You might want to verify spark plug current on each wire. An inductive timing light clamped over each in turn should verify spark on each cylinder under...
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    Force 75 threw a magnet at us

    The late flywheels with the raised center and larger bore have a different arrangement for the trigger magnets and the trigger coils have the bias circuit built in where the older CDI have the bias circuit in the CDI box, making the swap from CDI to CDM more problematic. The outer magnets are...
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    Force 75 threw a magnet at us

    That appears to be a late model flywheel ~1996+, but I have been wrong before. The trigger magnets would be different between the earlier CDI and later CDM engines and the diameter of the crankshaft would also be larger. It would probably fit a 1997 75 hp 3 cylinder engine. IIRC.
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    1994 Force Mercury 120hp No spark

    One way or the other if the black / yellow wire is grounded the ignition will not fire and you need to find where it is grounded (If that is the case)
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    Force 85 really difficult to start

    And you verified that the TDC mark on the flywheel is matched to tdc on the #1 cylinder.
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    1994 Force Mercury 120hp No spark

    Try disconnecting the rectifier/regulator (two yellow wires) and try again. Then check the black/yellow wire to see it that kill wiring might be grounded. It is grounded with the kill switch off if the ignition is off. sometimes the wire gets shorted to ground. I assume you tried all of the...
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    Force 85 really difficult to start

    If it ran good and now you have this problem is one thing. If it is new to you then it's Katie bar the door. Usually there is a single issue that suddenly causes the problem. Banging or back firing is something out of time (often). Make sure that the plugs are firing in the correct order. #1 at...
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    Force 85 really difficult to start

    The bangs could have blown out the transfer gaskets on the side of the motor and you have a leak there now, but checking the timing is a very good idea. Also if you turn the motor to start it and then pull the plugs are they wet with fuel and oil? The plugs could be fouled as well, but the...
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    Force 85 really difficult to start

    I saw above where the engine banged etc. I would check that the TDC mark is right as I said above. You seem to have fuel and the bang means that the timing is off. Perhaps check the TCD on the #1 piston and the mark on the flywheel agree and then a little starting fluid sprayed into the air...
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    Force 85 really difficult to start

    Did you check the TDC on the flywheel vs the actual TDC measured by pulling #1 plug and check with a screwdriver against the top of the piston? You may have sheared the flywheel key and the flywheel is out of sync with the crank. I have seen boats scrapped and the engines torn almost all apart...
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    Force 85 really difficult to start

    If the starter is dragging the starting RPM may be too low to get to the coming in speed for the magneto to fire the plugs. Have you checked for spark? For a quick check I use an induction timing light that at least proves that there is a strong current pulse to the plug. Check on all cylinders...
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    1984 Force 85HP starter will not operate - all wiring appears to be correct

    Every DC and most AC circuits needs to have two wires or connections, one for power and one to return that power to the source. Often in industrial electrical troubleshooting the technicians have problems when a fault occurs in the neutral or return side of the circuit.
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    Not permitted

    Not permitted, closed
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