Need Help how to start 3cyl merc

[sunbeam2]

I have at late 70's or early 80's 70 hp 3 cyl mercury. The airbox cover has a decal that says "Outboard can be started with electrical harness disconnected".<br /><br />Can you please tell me the procedure to run it with the harness disconnected.<br /><br /> There must be some wires that are jumped. The manual I have does not give any explanations.<br /><br />Thank you in advance, I have never worked on any engine larger then 15hp so this is all new to me

 

[sunbeam2]

Re: Need Help how to start 3cyl merc

I have had no replies.<br />Please<br />Is there anyone that can tell me how to start this motor without a harness connected to it??

 

[phatmanmike]

Re: Need Help how to start 3cyl merc

i know nothing of your particular motor, but that does N O T mean i know nothing ...<br /><br />if your motor has magneto style ignition, meaning it does not require the battery for ign voltage... you can disconnect the main harness and do as follows...<br />1. connect batt cables to selenoid and to good ground straight from battery<br />2. get a good length of wire and a momentary "push button" style switch, like this... look down...<br />wire it inbetween the pos+ batt terminal and the selenoid. whe you waht to star the motor, push the button, <br /><br />note: you will have to choke or unplug fuel line to kill motor<br /><br />if its got battery ignition... well than i simply dont know.. maybe this will help , maybe not<br /><br />button

 

[sunbeam2]

Re: Need Help how to start 3cyl merc

It has what this book calls "An alternator driven capacitor disharge ignition" <br />I do not know if that needs a 12v source to start or not.<br />I have the push button deal and I have spun the motor to check the compression, I did not see any spark on the plugs, perhaps they were not grounded properly.<br /><br />This book goes on to say that all tests that require cranking must be performed with the lead wires connected. What exactly does that mean, connected to the plugs, or the connected to plugs that are screwed into the head????<br /><br />I have a Seloc manula coming next week but I would like to see if it starts or at least tries to start now.<br /><br />What shall I do???

 

[sunbeam2]

Re: Need Help how to start 3cyl merc

On the right side of the engine there is an aluminum platform that houses the control box and the rectifier. This platform is installed on the motor with three rubber bushings that insulate it completly from the motor.<br />My wiring diagram show that the control box, the rectifier and all three coils are grounded to this platform. But the platform is not grounded at all. There is no continuity between the platforn and the engine block or any of the components on the platform to the engine block. This platform is not grounded at all.<br />I am not getting any spark.<br />The manual I have stinks<br />what should I do????

 

[sunbeam2]

Re: Need Help how to start 3cyl merc

please help<br />should I connect a ground wire and if so where

 

[randycc58]

Re: Need Help how to start 3cyl merc

with the battery connected to the engine, and the harness unplugged. find the possitive side of the starter solenoid. using a jumper wire from the large + to the small + should cause the sstarter solenoid to close and spin the starter. why are you trying to run it without the harness?

 

[DJ]

Re: Need Help how to start 3cyl merc

Realize that once you get it started, you will need to choke it to kill it because your ignition switch is no longer functional.