84 johnson 150 gt vro tach issues

[chronicblazed]

the tach dosen't read out, when you turn on the ignition it goes to 0, but dosen't read out any rpm when the engine runing, it stay's at 0 untill the ignition turns off then it goes to 1K or 2K. I'm not to familiar with boat engines, and basically want someone to describe the circuit so that i can troubleshoot it<br />any help would be appreciated thanks.

 

[Joe Reeves]

Re: 84 johnson 150 gt vro tach issues

Asher.... The three main wires that affect the tachometer are the Black (ground), Purple (12+), and the Gray (sensor). Since the needle moves when you turn the key ON and OFF, we can assume that the Black (ground) and Purple (12+) leads are okay. The fault would be with the Gray (sensor) lead or related components.<br /><br />Depending on which 1984 Johnson model 150hp you have, the engine incorporates either a Water Cooled Voltage Regulator/Rectifier on top of the engine just to the rear of the flywheel, or a Air Cooled finned type regulator which is bolted to the powerhead.<br /><br />In either case, there will be a Gray wire leading from the "Engine Wiring Harness" to a terminal block which also has a Gray wire that leads to the regulator. The "Harness Gray Wire" is the wire that sends the signal to the tachometer.<br /><br />To test the tachometer, temporarily move the engine harness Gray (tach sensor) wire from its present location to the Yellow/Gray (6 pulse stator lead) terminal, making sure that the connection is secure. If the tachometer now operates as it should (engine running of course), the regulator is faulty. If there is no change in the tachometer operation, either there is a break in that Gray wire or the tachometer if faulty.

 

[chronicblazed]

Re: 84 johnson 150 gt vro tach issues

thanks i'll give it a try

 

[chronicblazed]

Re: 84 johnson 150 gt vro tach issues

Joe thanks for the advice. It took awhile but i finally got around to testing the tach as mentioned above. I moved the gray wire to the location with the yellow/gray terminal. The tach came to life, moved the gray wire back to its correct location on the terminal, and strangely enough the tach still worked. Must of just had a bad connection? Now i have a new problem. after i did this the audio alarm on my throttle stick that usually goes off for a few secounds and then goes away when i turn the ignition on, now stays on constantly. I think this has something to do with the vro system? Please if you have any idea what may have happend plz let me know!

 

[chronicblazed]

Re: 84 johnson 150 gt vro tach issues

well i looked it up, and it means the engine got to hot ( it was running off a water hose on the trailer) or there was a fuel blockage problem. I think the engine got to hot running off the garden hose, luckly as soon as i heard the audio alarm i turned the ignition off.

 

[marinemech1]

Re: 84 johnson 150 gt vro tach issues

your oil tank sensor could be the reason for warning horn while horn sounding disconnect oil tank see if horn stops.<br />there are many many other reasons for horn to sound but oil tank sensor is one of the biggest

 

[Goldfish]

Re: 84 johnson 150 gt vro tach issues

If you ran it without water, I would almost bet that your water pump is toast now. Never run the engine wihtout water or turn it manually in the opposite direction of rotation. Replacing the water pump is easy anyways, and you should just buy a rebuild kit.