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1998 J70 TLEC Sync and link for idle?

A

Asport-16

Contributing Member
Ive been having a high idle problem. In goes in gear about 15-1600( i know its bad for my LU) i dont have any air leaks. Itll drop to 800-900 in gear. Where thats what it should be when at idle in neutral. Does a sync and link when done properly set your idle? My butterflies are closed in neutral at idle. The motor doesnt run with the air box off if thats info one of you good guru’s can use.
 
What spark plugs are recommended for that 1998 model 70hp? Are you using them?

Start with the basics.... What is the compression psi readings of the individual cylinders?... Then, with a tester whereas you can set a air gap, set the gap to 7/16" for the spark to jump. It should be a strong blue lightning like flame... a real SNAP! Is it?

NOTE that you can use a #2 philips screwdriver plugged into the spring connector of the s/plug boot... then hold it approximately 7/6" or so away from the block to test the spark... Have "all" spark plugs removed during the spark test.

If the above two areas are as they should be, do the following.... If either of the areas above prove to have a problem, hold off with the following.

With the throttle roller NOT touching the operating cam... check the throttle butterfly linkages between the carburetors to make sure that all butterflies close and open at the same time.

Set the throttle roller so that the butterflies just start to open when the scribe mark of the cam is dead center with the center portion of the roller.
 
(Asport's reply via a PM copied to the board here)
Asport-16 said:
I cant figure out how to answer your reply on the forum? No matter what I type an error message comes at me. So to answer your question about my high idle. I have 140 psi across the board. I have good if not great spark. It runs great at all rpm ranges. It seems as though it is stuck in quick start. I checked out the temp switch, took it out, it works but the part# is for a 150-225 johnson. Idk if thats the cause? The stock switch is unavailable. Im using stock Champion plugs set at 30ths. By the manuel. It runs really good since i did the work in all rpm ranges. At idle after it warms up it stays in quick start, shouldnt the timing base retard?
Click to expand...

I assume by the above you have roughly 140 psi compression on all cylinders, within 1 or 2 psi of each other?... and that the spark (with all s/plugs removed) actually jumps a 7/16" air gap with a strong blue lightning like flame...a real SNAP!... If this is so, fine, but if not, let us know as generalities doesn't tell us anything.

If the throttle linkages between the carburetors and the cam roller settings are as per my reply #2 which is important that they are... then as you suspect, I would agree that a problem exists with the "Fast Start" feature and/or the sensor.

Fellow members... Since this model is a 1998 model and I retired in 1991, I'd appreciate having you jump in here as I'm not familiar with the circuitry of this model.
 
Yes i have compression on all 3 cylinders. When this engine is cold it is at high idle from the timing base. Once it reaches 143’ the timing goes retarded to drop the idle down. Somehow the powerpack is involved in gear it goes down to 800-1000 rpms but in neutral it is 14-1600 in idle.
 
Has it always had this problem, or did it start out of the clear blue sky?
Got it Joe, Thanks. I'm no pro on this one either, where is Racer? Maybe Mr. Scott really left us, you know I really miss him.
 
Actually just before i did the work, I thought about it last night and then remembered it started when i changed the plug wites. There was an article i read put out from CDI explaining the complex circuits of how the bigger V-4 and V-6 Johnsons right down to their smaller engines like my 70 work with quick start mode. These engines also incorporated S.L.O.W. so an engine wont fry because of an overheat or lack of oil. The circuts that are effective right down to the plug wires. I put in Sierras. The manuel doesn’t say anything about the wires just the spark pugs. So idk maybe just a coincidence. Its probably going to cost me a few hundred just to find out. I guess Johnson did some experiments with their motors from 93-2001
 
Tstat is new. Yes i checked it with a pyrometer its normal temp. It supposed to retard the timing once it goes abouve 105’ then every time you start it for 10 seconds therafter. Mechanical work i can figure out pretty easy but electronics? Ouch! Even with the service manual its not easy to me anyway.
 
You can try a timing light on and see if its doing the timing adjustments as expected. The temp sensor ohm reading is to specs? Has anyone been playing with the idle adjustment screw? You can tell by looking at the paint. In the perfect world, this should never be changed from the factory setting. We are not in the perfect world by any means, but you are in Florida where the weather is quite moderate. I can't play with outboards all year long here in Minnesota, but the motors stay pretty mint here with no salt water as well as a 5 or 6 month per year usage. I have spent plenty time in Florida with my whole family bailing out to Orlando and Miami over the last 40 years, but I am "born" into the seasons and struggles that come with that.....just can't get myself to give it up. Without the struggle and pain, comes little jubilance or triumph. Like last night, up scrounging firewood out in the logging area north of us here with my 16 year old son, at -3 degrees F. We heat with ONLY wood, no backup.....done it for 16 years since we built this log cabin. The fire feels pretty darn good today, you take nothing for granted.....can't just turn up the thermostat.......don't have one. Yes, I'm a bit insane, but who isn't?
 
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May have a suggestion for you. Check out the power pack according to the instructions on CDI Electronics. If you look up the part number for it there. I was looking at the VOA etc tests that can be done.
 
Yes i live in Fl, but i came via Maine so know what your talking about Timguy. The temp switch? Now that may be everything. The one in my motor its for a 150-225 Johnson. The one they supposed to be in my engine is a part thats not produced no more. I wonder if thats why my temp gauge hardly moves? I know it works. Idk if the idle adjustment screw has been messed with not by me. The motor is 20 yrs old a lot could have happened over time. Quite a few boat shops around here dont want to work on it, b/c of its age.
 
Disconnect your remote cables for the time being from the trigger arm . then disconnect the linkage for the butterfly's from the trigger arm .then get a timing light and adjust the timing you will see the 2 screws the top one is the trigger stop screw for idle there is another one on the top of the block with a rubber stop on this one is for your WOT timing .put the timing light on no 1 piston HT lead .mark the TDC mark on the flywheel with white paint and also on the arrow indicator mark i don't know if your model firers on TDC or between TDC and 4 degrees i think its TDC [check this or someone on here may know] make sure your battery is fully charged turn the motor over and adjust the screw so that the 2 white marks line up as you turn the motor over with the key [ or get a press button switch and connect it to the solenoid ]. once you got the white lines lined up then before you connect the linkage for the butterfly's make sure they are all closed once you happy they are closed then carefully connect them to the trigger arm .make sure the trigger arm is against the idle stop screw .you may need to adjust the butterfly linkage to suite at all times make sure the butterfly's are closed and the top trigger arm is against the idle stop screw once this is done then check and adjust the nylon roller. the cam it rides on has a line on it this line should be in the center of the nylon roller and the butterfly's must not move when you do the final adjustment you can increase or decrease the ignition idling before you connect the carb linkage it should be +/- 750 rpm adjust it till you happy i always start the motor after doing the ignition timing before connecting the cables when you connect the cables do it carefully so that you do not move the trigger arm and adjust the cables to suite the trigger .i hope this may help you.
 
MjM3Njk-7dab6fb9.jpgno: 9 is the ignition timing idle screw adjustment
 
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