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  1. merc850

    1962 Merc 450 restoration ..

    Seems to me all you need is a new impeller in the waterpump, fuel pump diaphragm and you could be operational. I just noticed that that motor is possibly a manual model that's been converted to electric which explains the lack of motor wiring harness and the rectifier being where it is. The...
  2. merc850

    1962 Merc 450 restoration ..

    The I terminal is for battery powered ignition systems not used in this case, the large red wire is the +12v feed so you can hook it up to the B terminal. The only things that are going to have +12v to them (when you turn/push the key) are the starter and choke - the magneto makes its own spark.
  3. merc850

    1962 Merc 450 restoration ..

    Is this the other end of the control box wiring harness? The M terminals on the switch should be connected to the neg (engine ground) and the side terminal of the mag. The B[attery] terminal is connected to a +12 volt wire, the S term. is connected to the starter solenoid ( the one with the...
  4. merc850

    1962 Merc 450 restoration ..

    Yes you can "hard wire" the switch into the cable that goes into the control box (the best way is to solder the wires to the lugs); if it were my motor and I was going to use it full time I would clean up the motor end with better wiring [so you know what wire goes where] and no spade...
  5. merc850

    1962 Merc 450 restoration ..

    If your motor has an alternator (look for [2] yellow wires) on the Stbd. side that run from under the flywheel to the rectifier, you can get a standard marine tach to tell rpms. which is important for proper operation {5,200 - 5,600 rpms}. When you re-install the driveshaft and shiftshaft in the...
  6. merc850

    1962 Merc 450 restoration ..

    Way back (7 or 8 years) there were a lot of Merc catalogs, ads and memorabilia online so I bought all I could, this is a page from the 1961 Catalog; definitely the long shaft model.
  7. merc850

    1962 Merc 450 restoration ..

    The magneto has a post on the side DO NOT put +12v on this post it is grounded to kill the spark. If you can, hook up the electric choke it will make starting it easier and connect the alternator and rectifier to the + side of the battery so it isn't destroyed; connect the throttle cable too so...
  8. merc850

    Mariner 15hp 2 stroke id

    Post a picture of the cowling - someone should identify it by the colors. I think Mariners came along when breakerless ignition was standard.
  9. merc850

    1962 Mercury 500 E 50 horse no spark

    DO NOT put 12+volts to the terminal on the side - this is grounded to stop engine, check for a ground wire from block to magneto case, lightly sand the points then clean them with alcohol.
  10. merc850

    Motor only fires up when key is turned to off

    The 1st page of the pdf is for testing the CDI replacement switchbox it's the second page that tells you how to troubleshoot the trigger, the trigger wires are on the port side of the engine.
  11. merc850

    Motor only fires up when key is turned to off

    The only mechanical problem is the trigger disk might not be turning with the shaft, you could check that.
  12. merc850

    Motor only fires up when key is turned to off

    You can't see the problem because it's usually in the electronic circuitry that's why you have to use the pdf troubleshooting guide.
  13. merc850

    Motor only fires up when key is turned to off

    The merc switch is a safety device not needed for regular operation. The pdf will tell you what will happen. When you get it running don't rev the crap out of it on the driveway - keep the revs about half throttle.
  14. merc850

    Motor only fires up when key is turned to off

    You can also have a friend hold onto the spark plug wire while cranking.Ha Ha trick or treat! Recheck the timing (should have mentioned that first).
  15. merc850

    Motor only fires up when key is turned to off

    That system uses a trigger that is located in the distributor and one sign that it's bad is the problem you are having. Are all the wires in good condition no bad insulation or copper? Remove the mercury switch wire from the switchbox and see if it will start. Remove the distributor cap and look...
  16. merc850

    Motor only fires up when key is turned to off

    Identify the ignition system from these 2 diagrams.
  17. merc850

    1978 Mercury 500/50hp help!!!

    Look for Mercury Marine 1975 thru 1978 C-90-75512 the break in mix is 25:1 the run mix is 50:1; your motor should've be broken in years ago.
  18. merc850

    Mercury artwork

    I have created some artwork that's Mercury themed and is available from Fine Art America (https://fineartamerica.com/) just type Murray Dowding in the search box; you can get 15oz coffee mugs, T-shirts, puzzles, shower curtains etc. Here's the latest shirt I received - the edges are not...
  19. merc850

    1975 Mercury 650 starter issue

    Put your voltmeter on the battery terminals and turn it over - then put it on the starter terminals and turn it over, the voltage should be the same (approx. 11v) if it's low the battery is weak or the solenoid connections are not clean.
  20. merc850

    Starting and maybe restoring old Mercury 402 40hp

    The Merc 400 motor that preceded it had crank breakage problems due to owners over propping them which caused them to run under the rpm range, ie lugging; the fuel pump was water cooled to reduce the possibility of vapor lock and the mercury switch prevented overreving if the motor hit an...
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