mercury timming

Discussion in 'Bubba's Outboards' started by crackers, Jun 17, 2009.

  1. crackers

    crackers New Member

    Messages:
    296
    State:
    Arkansas
    I have a 1978 115 mercury, and put a timming light on the no.1 plug and checked the timming on it it says on the front of the engine timming is at 23 degrees btc but mine seems to be at about 9 degrees, how should i set the timming. this was at idle. with a water hose connected to the engine. looks like theres two bolts at he top of the distributor and turn till its in time then retighten but i want to know for sure before i go and start turning things with out knowing.
     
  2. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    You're fixin' to hurt something.:wink:

    But, it's your engine.
     

  3. crackers

    crackers New Member

    Messages:
    296
    State:
    Arkansas
    I know it, so thats why im waiting to be sure some one can tell me how to do it right,
     
  4. Bill in SC

    Bill in SC New Member

    Messages:
    4,451
    State:
    South Caro
    I forwarded this message to my brother who is a certified Mercury mechanic. His reply to me was:

    Bill:

    The 23 BTDC is at WOT (wide open throttle) or MAX timing. 9 degrees at idle sounds OK

    This can be checked at cranking speed with the throttle wide open.

    Remove ALL plug wires. If you leave 1 plug in and crank at WOT, it will start and run wide open on one cylinder, possibly blowing it up

    Ground #1 to block.

    Advance timing to MAX

    Check timing while cranking engine.


    Hope this helps...

    Bill in SC
     
  5. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    That's why I posted what I did.

    If it ain't broke, don't try to fix it. Your wanting to adjust timing, for what reason?
     
  6. Bill in SC

    Bill in SC New Member

    Messages:
    4,451
    State:
    South Caro
    I was wondering "why" too? Obviously the engine is running rough, lacking power, or some other sort of symptom. Probably carb or some electronic problem with an engine that old. I'm hoping he will continue with some additional info so we can help him get it diagnosed.

    Bill in SC
     
  7. crackers

    crackers New Member

    Messages:
    296
    State:
    Arkansas
    thank you for that information, and the reason i was asking is because on the last trip at the end of last summer it started running rough and then died on me and took me foever to get to the boat ramp and that was only about 50 yards from the ramp. sorry me didnt have no trolling motor and had to use the oar. this was on a pontoon 24 footer. I was not up to the task so when i got it in I stripped all fuel lines from the engine cause some fuel was dripping on the water, not a good sign. cleaned all carbs and set the floats. just started it up day before yesterday and it started right up and sounded good. bulb was tight after just a few squeeses. just making sure every think is ok tbefore i go around on the river. putting a trolling motor on this time for two reasons one to troll and the other to use it if the engine wont start. I do not like oaring for a long pierod of time I will leave the timing alone and see what it will do in the lake and go from there...
     
  8. crackers

    crackers New Member

    Messages:
    296
    State:
    Arkansas
    this brings up a question, how do you check out your engine for WOT with out putting it in the water,or how do you tell if your engine will perform good on the lake and not stall, if it runs good at idle with the water hose hooked up to it and it does not have any fuel leaks. I dont want to open my engine to full throttle just with the water muff on it.
     
  9. Bill in SC

    Bill in SC New Member

    Messages:
    4,451
    State:
    South Caro
    I can't answer the last question, though I can check with my brother. BTW: if your boat was leaking fuel on the water, most likely there was a piece of trash causing the needle not to seat in the carbs. That said, it would propably run good at speed, but idle erratically. If you have cleaned the carbs, you should be OK. Always crank that Merc trimmed ALL the way DOWN, at least when cold. Fuel gets to the lower carb by gravity, and they are designed to be cranked while down. Test it out and by all means, post up your results. BTW: You can rev your engine up on the muffs, but I wouldn't want to hold the throttle wide open on them.

    Bill in SC
     
  10. crackers

    crackers New Member

    Messages:
    296
    State:
    Arkansas
    You were right about trash in the carb,and had a fuel line that had a small crack right at the nipple of the carb. thats when i replaced all the fuel lines and removed the carbs and cleaned and checked for dirt, cleaned out my tank at that time and added fuel stablizer too for the winter. got it out for the first time this year on the muffs and trying to get it ready for the lake, late start because of moving and every thing else comming up but it did start right off, also replaced a few wires in the engine compartment with new ones the others were old and brittle then coated them with liquid tape to waterproof them there still in good shape,or the liquid tape seems to weather good and not peel off. will keep you posted on the results