• If this is your first visit to the iboats.com Boating Forums, be sure to check out the FAQ. To post a question or comment, begin by signing up. To start viewing messages, select the forum that you want to visit from the selection below.

Announcement

Collapse

Help Tip: If you have a question that has not been answered to your satisfaction in the archives, it is always best to start a new thread of your own. By starting your own thread, you will receive the maximum number of views by forum members.

Below are some additional forum policies in hopes of all iboats members will follow, Thank you.

1. Please do not reply to old topics or hijack existing topics. Old topics of a technical nature are like a library book, Please do not write in them.

2. Old topics should be considered archives and used for reference only. Please do not reply to them.

3. Do not take over someone elseís topic (aka hijack) with your own question, even if it is similar. If you have a question that has not been covered to your satisfaction in the archives, it is always best to start a new topic of your own.

4. If you have a question for the original poster (OP) and the topic is over 30 days old, send the OP a PM, he may not even visit the forums any longer, or may not notice your question in the old topic.

5. By starting your own topic, you will receive the maximum number of views by forum helpers that may not even notice your question when itís posted at the end of someone elseís topic. And those answers will be specific to your particular issue.

6. Please do not post to topics that have been inactive for more than 3 months unless you are the original poster. We have very active forums and any topic that remains inactive for that long should be considered "dead". It is especially confusing when there is an entirely new question posted to an old topic.

7. Posting at the end of any topic is considered to be hijacking the original posters topic which in turn subjects the topic to be closed if it continues to happen thus not making it fair to the original poster in the future had for some reason he/she needed to return for additional information or provide an update of the problem solved which is always welcomed within a reasonable amount of time frame.

8. Please note that you should see a red banner pop up near the bottom of each inactive topic asking you not to reply to old topics. The Red banner will read: Please note this topic has been inactive for 90 days. For the best results, please start a new topic.

Thank you all in advance for doing your part in helping iboats run a smooth ship.

Additional forum rules linked below.
http://forums.iboats.com/forum-rules-guidelines-405/
See more
See less

1982 70hp Johnson Timing, spark plug questions

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts


  • 1982 70hp Johnson Timing, spark plug questions

    Hello all,

    I will shortly be replacing the stator and timer base in my engine. I have gone with CDI parts for these items.

    I have read various threads in regards to spark plug gaps etc and sticking with forum rules have started a new thread, i'm sure this has been done to death.

    Firstly can someone tell me in METRIC what should the gap be set to? I have the NGKs and a set of Champions.

    Secondly, i have a workshop manual, but just wondering with the demise of leaded fuel, how does this effect timing etc on this engine?
    As i understand it, unleaded fuel degrades faster than the old leaded stuff and if old will effect detonation.

    If there is is a thread for setting the timing for this engine could someone link it?

    I appreciate all replies as usual this forum has been of immense help.


  • #2
    Re: 1982 70hp Johnson Timing, spark plug questions

    recomended plug L77J4 , Gap , 0.040 inch , metric 1.01600 mm , after you fitted every thing & pluged all the plugs in , provideing you have not turned the idle ajusting screws . the 2 that are spring loaded by the trigger to the right of it your timeing should be some where near , best to double check , get a timing light connect to spark plug no 1 [top one ] , turn the motor over useing a strong charged battery aim the timing light at the pointer it should fire TDC , mark this with a little white chalk easier to see , when i do the wot timing i disconnect the carb linkage & at idle move the trigger in anticlock wise direction the timing light should then flash on 19 degrees RPM idle should be between 700-750
    the 2 spring loaded screws by the trigger turn the bottom one clockwise to advance & anticlockwise to retard

    Comment



    • #3
      Re: 1982 70hp Johnson Timing, spark plug questions

      The correct plug is a QL77JC4 and metric gap is .7620 (factory spec is .030). Install your new parts and take a dial indicator and check to see if timing pointer is at TDC. Remove the spark plugs and ground #1 plug. Take a timing light and attach to #1 plug, remove the throttle cable and advance it to WOT position. Use a remote starter or have someone turn the engine over and check timing. If timing needs to be adjusted it is set by loosening the lock nut on timing screw behind #1 carb, screw in to retard and out to advance the retighten lock nut. With todays fuel I usually retard timing 2į from factory spec's. Reattach cable and plugs,start engine and if on a hose set the idle rpm to about 1000-1100rpm as when you get it in water the backpressure will cause the RPM to drop down into the 750-800 range...
      the 2 spring loaded screws by the trigger turn the bottom one clockwise to advance & anticlockwise to retard
      ?????????
      When in doubt,Trim it out!!!
      Business Owner & Certifed Technician
      Boats I own & use
      20ft Javlin w/250 Junkrude
      17ft Bullet w/200 Merc (SOLD!!)
      13ft Allison w/150 I-6
      17ft Hydra-Sport 175GT
      15ft Allison w/75 Stinger(project)
      14 x 48 Drifter with 1100SS Merc

      Comment



      • #4
        Re: 1982 70hp Johnson Timing, spark plug questions

        Thankyou very much guys. I have the QL77JC4's.

        Comment



        • #5
          Re: 1982 70hp Johnson Timing, spark plug questions

          the 2 spring loaded screws by the trigger turn the bottom one clockwise to advance & anticlockwise to retard
          the reason why is because when you turn the screw in clockwise the timer base moves in anticlockwise direction when the flywheel comes round in a clockwise direction the groove on the inside of the inner diameter is gonna trigger the sensor off to spark before the piston gets to top dead center , check it out for yourself .......?

          Comment



          • #6
            Re: 1982 70hp Johnson Timing, spark plug questions

            These screws do nothing for the max timing... the top screw is the throttle stop to keep butterflys/shaft from"camming over" or going past the horizontal position and lower is the idle adjustment screw...
            Attached Files
            When in doubt,Trim it out!!!
            Business Owner & Certifed Technician
            Boats I own & use
            20ft Javlin w/250 Junkrude
            17ft Bullet w/200 Merc (SOLD!!)
            13ft Allison w/150 I-6
            17ft Hydra-Sport 175GT
            15ft Allison w/75 Stinger(project)
            14 x 48 Drifter with 1100SS Merc

            Comment



            • #7
              Sign up today
              Re: 1982 70hp Johnson Timing, spark plug questions

              Thanks for the pics Faztbullet, very helpful.

              Comment


              Working...
              X