65HP Mercury Charging and Idling

Discussion in 'Bubba's Outboards' started by turtle1173, Sep 5, 2007.

  1. turtle1173

    turtle1173 New Member

    Messages:
    611
    State:
    Mayfield, KY
    I recently got a 1971 65 HP Mercury. It has run very smooth and idles beautifully. Took it out Saturday and everything was normal. While I was out there, it suddenly started idling poorly. In fact, it took several tries to get it in gear before the motor died. After getting it in gear, we headed closer home, which was a several mile ride. I throttled the motor down to talk to someone and the motor died. I went to start the motor and the battery was completely dead!:sad2: We came in on the trolling motor.

    I have thought it odd that my fishfinder only shows the battery at 12.0 - 12.4 volts, even while the engine is running. My other motor ('88 60hp Merc) always showed 14-16 volts while running.

    When I got home, I removed the cowling to have a look. I knew some of the wiring was needing some attention but was surprised to see more serious wiring issues. Much of the wiring insulation is just falling apart in places. Cracks, breaks, wires barely holding together in spots, etc.

    I noticed the red wire coming off the rectifier (that goes to the switchbox) crosses over the ground wire that goes from the harness to the starter solenoid. There is bare wire (on both of these) where the two cross. That surely can't be good and may be why my battery isn't charging.

    I know I'm going to be replacing some wires and doing some splicing. I am wondering though if any of these wiring problems have to do with my sudden idling issue. I'm thinking it must but am unsure from an "electical perspective" how that would come about.

    Thoughts??

    Thanks!!
     
  2. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Shane the first thing you want to do is to take that wire loom off one section at a time and replace each broken or frayed wire with new wire. I doubt you can find a new wire loom for that 850. Now they were good motors but the wireing or should I say the sheathing around the wire ing was not the best in the business. That recetfier will have to be replaced. You can take some of the wires and coat them with liquid tape. This works on most wires that doesn't move when on the engine.
    The recetfier shouldn't have made the engine quit. If that engine sat for awhile you are going to have to remove those carbs and soak and rebuild them. Those drop bowl carbs from those years were fineky about trash in them but very reliable carbs when set right.
    I hope when that recetfier shorted out it didn't get back up under the fly wheel to get to the stator or switch box. I have some test if I can locate them that will tell you how to test that stator and switch box.
    On a good note if you have good compression parts can be still had for that motor.
    I loved listening to those ol 850 singing across the water but they are a bugger to work on as every thing is cramed into one little tight place.
    After you get the wires from touching put the muffs on and squirt some premix into the carb and see if she will fire back up. If she hits then I suspect the carb or fuel system to be the bad boy.
     

  3. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    MERCURY BATTERY-POWERED CDI TEST
    FOR DISTRIBUTOR MODELS

    This test is for the 332-2986 switchbox used from 1967-1978 on all the inlines.

    This test assumes your coil is good (most all are).

    DISCONNCT BATTERY

    1. Turn off ignion
    2. Disconnect all 3 wires on the distributor side of the switchbox.
    3. Remove the HV lead from the coil to the center cap (remember it unscrews
    from cap)
    4. Reconnect that HV center lead to the COIL side only.
    5. Position that HV lead about about 3/8" from ground (block, shrouds etc)
    and find a way to hold it there.
    6. Jumber the brown and white terminals on the dist. side of the switchbox
    together.

    RECONNECT BATTERRY

    7. Check that you have +12 V at red terminal.
    8. Turn on ignition and verify +12V at white terminal (on red terminal side)
    9. Touch the black terminal to ground - unit should cause spark each time
    you touch ground.










    The first simple check is to assure that you have +12V on the red and white wires of the switchbox, when the ignition key is on. No voltage on both = no spark at all.



    Check the Trigger. Disconnect the Brown/white and the Brown/Yellow wires from the switch box. Test the resistance between them. You should have 750-1400 Ohms. If not you have a bad trigger. If you do get these readings then Check voltage going ti coils from the switch box. Each coil should have 180V+



    Timing and Sync of Merc Inlines (to 1988)

    Manual specs are different for each but this is close enough to get them all REAL close. This assumes nothing is broken or "wrong" with it. This also assumes that the timing pointer is properly adjusted (if adjustable) to accurately read TDC of the #1 piston. This basic procedure will work for all the 2/3/4/6 cylinder inlines from 1960 to 1988. It's not for the newer 3 and 4 cylinder loopers. Engine off Disconnect throttle cable Pull throttle arm to full throttle and verify carbs open fully. Adjust main throttle stop so that the carbs are JUST hitting thier own little throttle stops. The idea here is that you want the screw stop and NOT the carbs acting as the "final stop" for your throttle lever. Return the throttle to idle, carbs should be closed. Set all idle screws to 1 3/4 turns out from lightly seated. Remove all plugs except #1, hook a timing light to #1. Then follow the narritive. When the throttle is in the idle position the carbs should be fully closed and the ignition retarded. It is the amount of retardation that determines your idle speed and is set later with the idle stop screw. Timing Event One - throttle pickup. As you continue to advance the throttle the timing will advance while the carbs slowly open a bit more. The next adjustment is max advance, this is the point where the distibutor (or trigger) can advance no more. Set the max-advance stop to 21 degrees for "direct charge" crossflow inlines and 34 degrees for the older plain vanilla crossflows. Use the light, - err to the side of caution. Right after max advance, further throttle motion should cause the second throttle pickup to hit and open the carbs to full. You already set that -now verify it. Leave the throttle cable disconnected and go to the water. Leave the boat strapped to the trailer and back it in so it's deep enought to run. Have a friend crank it while you operate the choke and throttle. Warm it up at 1500 rpms's. When "warm" adjust the idle stop screw for about 800 rpm and then ajust your idle needle(s) in (one at a time) till the motor stumbles. Quickly backing it out 1/2 turn from "stumble" will usually save it from needing a re-start. Do that for all the idle screws. Re-set idle stop for 800. Now have your friend put it in gear (make SURE you are on the transom NOT in the water) and reset your idle stop for as low as you can get it. 500-600rpm is great if your old reeds will let it idle that low in gear. Now, re-adjust the idle screws, in to stumble, then 1/2 turn out. When you've gone back and forth with that a few times and have it "perfect" - adjust each one out 1/4 turn. Reset the idle stop so that it's about 700-800 out of gear and 500-600 in gear. Sometimes bad reeds won't let you get that low, you've GOT to get it under 1000 in neutral (worst case) to avoid beating up your lower unit when you shift into gear, even 1000 is "bad" but like I said "worst case". Now adjust (and hook up)the throttle cable so that with the shifter in neutral, there is light to moderate pressure holding the throttle arm against the idle stop. Take the boat off the trailer and go out in the water. Try the hole shot. If it falls on it's face try adjusting the idle screws out 1/4 turn at a time (all of them together) till you can get a hole shot. You can kind of do this on the trailer at the ramp, but it's not really safe for you, the boat, or the tow vehicle. You're done. -W
    __________________
     
  4. turtle1173

    turtle1173 New Member

    Messages:
    611
    State:
    Mayfield, KY
    Willard,

    Thanks for all the info. Just a couple things: The motor hasn't set up any. It has been maintained good and has been well taken care of. I've had it out probably 7 times with no troubles with idling, starting, running or anything.

    By "wire loom" I'm guessing you are talking about the internal wire harness? How will I connect new wires to that big black plug or will I just splice them in before the plug?

    Just to verify, I can run the motor with the rectifier not working? Also, will the new style rectifier (square type) work on the motor? I can't seem to find the kind that looks like what I have.

    Thanks again!!
     
  5. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    By you having it out that many times I would start check for air leaks from the carbs all the way back to the tank. I would replace all the fuel lines from carb back. Cheap fix and is nesseary about every two years.

    Yes the wire loom is under the hood. all wires included.
    As for the wires coming out of the different sources that you can't access trim back as far as the wire will permit and re sordier new wire in its place and heat shrink the conections.

    Yes you can run it without the recetfier and I'll have to check that recetfier to see if it will work.
     
  6. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    BTW shane get me a serial number off that motor and let me cross reference the recetfier.
     
  7. turtle1173

    turtle1173 New Member

    Messages:
    611
    State:
    Mayfield, KY
    Willard, the serial number is 3074479.

    After repairing a few wires, I hooked her up to the hose. Before turning the water on, I started pumping the bulb. Fuel was leaking out of the top carb. I'm guessing the needle valve is stuck open or something like that.

    I went ahead, turned the water on and the motor started right up. However, it wouldn't idle down without dying.

    So it's time to tear the carbs down I suppose. What a pain in the neck even trying to get to them :crazy: I'm about to go crazy cause I can't get to the bolt behind the coil that holds the front support on. I'm sure not moving the coil with the fickle wiring (if I can help it).

    I ran the motor with my fishfinder hooked up. It still read 12.4-12.5 volts. I suppose under normal running conditions with a good rectifier, this would read higher, right?

    Thanks again!
     
  8. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Yep it should read higher.

    You will most likely have to remove that switch box to get to that nut. I have taken a long flat screw driver and a small hammer and loosened those nuts up.

    She won't idle down because the carb is loading it up with excess fuel.
    Hang in there and get it done. those old mercs were about bullet proof
     
  9. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Shane the orignal parts number for that recetfier is MM7814A1
    It shows the orignal to be square. If the one you have or is getting has the same color wires then use it I don't think the shape has much to do with it except when its a water cooled recetfier and that 650 shouldn't be water cooled.

    The serria number for an after market on is SIE-185707 Hope this helps in narrowing it down.
     
  10. turtle1173

    turtle1173 New Member

    Messages:
    611
    State:
    Mayfield, KY
    Willard,

    I started tearing down the motor to get to the carbs. MAN, what a mess. I got to the point where everything was removed except for the starter, distributor and coil. Of course the carbs were still buried in that. The starter was going to have to come out but the screws to do it were just about inaccessible.

    I opted to take it to a mechanic friend of mine. He had some weird swivel headed rachet that was able to reach the unreachable, LOL.

    So for $80 he finished what I started, cleaned the carbs, and put it all back together. Plus, I didn't lose a bit of sleep over it, LOL.

    Anyway, I asked him about the carbs. He said he didn't think they had ever been cleaned before (this is a 1971) and that it had quite a bit of rust in it.

    He ran it for me on the hose. It sounds great and idles down good. I'm taking her out tomorrow!!

    Oh yeah, he also verified that it's the rectifier that is out and not the Stator. So that's good news on that!!

    Thanks again for the help!!
     
  11. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Thanks for the follow up shane and if those carbs have rust in them then get rid of that metal tank and install a fuel water seperator on it. Mount the fuel and water seperator on the boat and run the hose with the bulb on to the engine from the filter.