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Tachometer 90 horse mercury outboard engine quit working any suggestions

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Hi Royscarrow,
This Could Be A Few Reasons Causing The Tachometer Not To Work.
The Voltage Regulator Mounted In The Engine Compartment Has A Grey Wire Coming Out Of It Together With Two Yellows,Two Red's and One Black. The Grey Wire Is The Sender For The Tachometer.
Check That It Is Connected.
Is The Battery Getting Charged When The engine Is Running?
Is The Potting In The Regulator Discolored Or Burnt Looking ?
Check The Plug For The Gauge Loom At The Control Box Is In Correctly.
Let Me Know What You Find.

Posted on Apr 04, 2015


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Posted on Jan 02, 2017

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SOURCE: I have a 90 Horse power Mercury outboard Boat

Sounds like the starter. Check if you have power at the solenoid from the battery with just the power on (key turned on, power switch on.) thats good-- you have power-- if not you have a wiring problem from your battery or main switch.

Otherwise you have a starter problem probably.

Posted on May 17, 2009

  • 5677 Answers

SOURCE: I have a 1984 90 horse Mercury outboard motor and

If there is a difference in end play see if there is more play in the throttle cable than in the shift cable. It may be switched in either the motor end or the shifter box. Or a gear inside the shifter (less likely) is reversed. The only other idea I have is if that does not work to test the location of the shifter and let it hang down freely. The cables are grouped in sizes like 15 to 17ft, 17 to 19ft, and so on for a reason.

Posted on Jun 11, 2009

  • 5677 Answers

SOURCE: mercury 90 outboard transmission slipping

Check your prop hub. The rubber isolator is probably bad.

Posted on Jul 06, 2009

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SOURCE: I have a mercury outboard 50hp engine that will not start

If you are saying the Flywheel is locked or Frozen then I imagine the starter Bendix was found extended and jammed against the Flywheel.

If the motor ran when it was shut off last, then your rings and/or bearings rusted in place. You don't want to grab the prop to turn it because it will strip the Rubber hub.

I would take out all the spark plugs, tilt the engine up as close to level as you can get it and spray WD40 into the cylinders. If you did not have water connected to the engine the pump may have crumbled but if the engine did not turn at all the pump may still be good.

Give the WD some time to penetrate and crank the engine to see if it broke loose. If it did not, you may as well drop the lower unit and eliminate jammed gears with a second try at cranking the engine.

If still no luck, you might try to rig an Air fitting to the Sparkplug holes and hit each with about 80PSI and another squirt of WD. This will force the WD deeper and force the pistons down with no damage.

Still no luck, then its disassemble time. Good luck on this.

Posted on May 27, 2010

  • 747 Answers

SOURCE: 1987 90 hp mercury outboard kills when putting it in gear

sound like a fuel issue if the engine set for a long period you may need to clean the carburators sounds like they are clogged

Posted on Jul 07, 2012

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