Starting trouble '96 70hp

[hortguy]

I have been having increasing trouble starting my '96 70hp Johnson (J70TLEDA). I can pull start the motor, but it will not start with the key (starter turns over, occasional pop of motor firing with smoke out exhaust). Once the motor is warm, it starts easily with the key all day. I hate starting the day pull starting by boat in front of guests, it doesn't really instill confidence in the trip!

I replaced the battery, the plugs and plug wires and still had no start with the key. I disconnected the yellow/red wire from the starter solenoid and attached a remote switch. With the ignition in run, the remote switch started the motor instantly!

I did a continuity test on the key switch and everything seems fine. I checked continuity on the yellow/red wire from switch to solenoid and it checked out. I reattached the yellow/red wire to solenoid and tried again but nothing. I ran a temp wire from the starter switch to the solenoid. The motor starts fine without the yellow/red wire attached but won't with it attached.

The wiring diagram shows this yellow/red wire going to the power pack. Could the power pack be my problem or is there something else I should check?

Mike

 

[hortguy]

Re: Starting trouble '96 70hp

While picking up my tools, I decided to take apart the main ground on the engine and clean it up even though it looked good. It wasn't too bad but cleaned it up and put back together. I took the battery charger off and bumped the key with the start wire (yellow/red) attached to the starter solenoid and she fired right up. I turned it off and tried again which gave me a weaker start. A third try gave me nothing.

I'm guessing here. Voltage issue? The surface charge from the starter would have had the voltage out of the battery higher than normal which seemed to push me over the hump. I guess I'm back to tracing grounds again, but I'm still hoping for some ideas.

 

[jtexas]

Re: Starting trouble '96 70hp

You sure the yellow/red goes to the powerpack? I don't have your year wiring chart but I would've sworn it terminates at the solenoid and the keyswitch.

When you turn the key, does the motor turn over? does the solenoid click?

Which solenoid terminal did you attach your remote start switch to? And which terminal did you attach your jumper wire from the keyswitch?

Get hold of a multimeter & measure the voltage of the yellow/red with the key turned to "start". Also the battery open circuit voltage.

 

[hortguy]

Re: Starting trouble '96 70hp

Yep, the yellow/red comes from the keyswitch to the motor then splits and one leg goes to the solenoid and the other to the power pack. With the key, the motor turns over just fine but no run (occational pop, sometimes LOUD!).

I attached the remote start switch to the pos lead from the batt and to the top small terminal (where the yellow/red wire goes). When I used the jumper wire, I attached it to the same tab on the keyswitch that the yellow/red wire connects (should be the S tab although I didn't look since I haven't changed it since it was working ok) and to the same top post on the starter solenoid.

The open voltage on the batt was 12.6 volts when I started this afternoon but I didn't check it with the starter running. I had the charger on it while I came in and fixed dinner so the voltage was probably a bit higher (surface charge) when it started 2x after dinner. I hope that makes sense.

I'll check the voltage while running the starter tomorrow while I'm checking every connection I didn't take apart and clean today. Is there a particular voltage the power pack wants to see to start?

 

[jtexas]

Re: Starting trouble '96 70hp

sorry, forgot about the "quick start" feature, in which the powerpack controls the spark advance until the engine warms up. a search of this forum for "quick start" (with quotes) turned up this thread: http://forums.iboats.com/showthread.php?t=109936

 

[hortguy]

Re: Starting trouble '96 70hp

Thanks for the link to the quick start thread, it gave me a couple of other things to check and helped me understand what that system does. Ok, I checked some things and ran some tests. I did have the black/yellow and black/white wires on the key switch reversed if that matters.

I started out with 12.65 v at the battery (went to 12.5 after cranking a few times and stayed there when there was no load). I had 11.3 v at the battery while cranking.

At the engine, I had 12.5 v no load at the starter and 10.4v while cranking. I had 10.3v on the yellow/red wire (start wire at solenoid shared w/power pack). Checking the cables, I have about a 0.4v drop from the battery to the motor while starting on both the pos and neg and I have continuity (0 resistance) from the different grounds on the motor to the neg terminal on the battery.


The temp sensor tested open to ground (which it should).

I don't really have a way to test the timing advance, but from the sound of the starter I would say that the motor is advancing. There is a noticable difference in engine and starter sound between turning over with and without power on the yellow/red wire.

With voltage on the yellow/red wire, there is only one spark on the plugs as I release the starter. With no voltage on the yellow/red wire, there is a nice blue spark at about 1/2" gap. Could this be timing?

 

[jtexas]

Re: Starting trouble '96 70hp

timing advance refers to the point at which the plug fires in relation to the position of the piston in the cylinder - it doesn't affect the starter.

could be temp sensor, could be powerpack.....start a new thread with the words "quick start" in the title, to get the attention of somebody with more knowlege of that feature.

 

[hortguy]

Re: Starting trouble '96 70hp

Thanks, I couldn't have narrowed it down this far without your help.