Johnson 70hp cdi problem ??

[Bede501]

I own a Johnson 70hp 1996 model. All electrics are fine except for the temperature alarm which does not work. I dismantled the blocking diode from the engine block and it grounds when placed in boiling water so it should be ok. The Quickstart function does not work too ... thats why I suspect the CDI with respect to temperature is not functioning. Anything else I should check to make sure ?? Otherwise all is fine.

 

[rickdb1boat]

Re: Johnson 70hp cdi problem ??

Have you checked the temp. sender? Look on the back of the engine block just to the side of the top spark plug. You should see a tan wire connected to the temp. sender. Disconnect it and ground it to the block with the key in the on position. See if the alarm goes off.

 

[Bede501]

Re: Johnson 70hp cdi problem ??

Hi Thanks for replying.<br /><br />When the sensor is removed and grounded the temperature alarm does not sound (with ignition on). However the resistance was checked with a multimeter and it reached 0 on grounding which means the temp sensor is ok .. right ?

 

[ob]

Re: Johnson 70hp cdi problem ??

Bede501,Are you grounding the tan wire or the temp sensor itself? Need to ground the tan wire with the key in the 'on' position.I'm wagering that your quickstart issue is a faulty temp sensor.Bare in mind that if the alarm does sound while performing this test it only verifies thast the alarm circuit is complete and does not verify that the sensor is working properly.You can either peel back the bullet connector insulation to ground the tan wire for test or backprobe it with a test lead.

 

[Bede501]

Re: Johnson 70hp cdi problem ??

Hi thanks for the reply.<br /><br />Ok so if the tan wire is grounded and the alarm goes on it means the alarm is working. I have a question here ... For the engine to sense an overheat situation and engage SLOW function it must have a temperature input (I guess to the CDI) that engages the slow function. Is the input from the temp sensor to the alarm the same input as for the CDI ?

 

[Bede501]

Re: Johnson 70hp cdi problem ??

Hi. Ok I cleared out some stuff in my brain. <br />So yesterday I grounded the tan wire and the Hot led lit up !! This means that the Hot alarm works. I checked continuity on the temp sensor at room temp and both the tan / blue and white / blue wires showed no continuity. This shows that at 25 degrees the temp sensor works fine. <br /><br />Why could my Quickstart not be working so ??