help!!! no spark. 1974 ,85 hp, mecr

[dwcawags]

Thunderbolt ignition on a 85 hp merc(1974). 12 volts constant to the switch box and the rectifier. Do not get any current to the coil when cranking the motor. For a brief instance you get 12 volts going to the coil when you shut the key off and engine stops cranking.<br /><br />signed confused

 

[Reel Appeal]

Re: help!!! no spark. 1974 ,85 hp, mecr

dc,<br /> Do you have a manual on the motor?<br /> Make sure your battery is good and full charge.Shift control is in neutral.Check connections(wiring)and grounds.Is the ignition switch in good shape?There may be a fuse installed between switch and solenoid(red wire),check if equipped.<br />A manual would really help as it contains detailed instructions for testing components.

 

[12Footer]

Re: help!!! no spark. 1974 ,85 hp, mecr

Remove the dist cap, crank, and insure the rotor is actually turning. If not, the dist drive belt has failed. If it does turn, see if you can take one finger,and rotate the rotor (gently, do not force), by hand. If you can, the rotor has stripped out at the dist shaft (they have a habit of doing this). <br />Merc used some kind of water proofing goo on the dist assembly. It is a clear, tar-like substance. Sometimes, this goo 'melts', or runs down inside the dist cap. It can 'glue' the rotor in place,which tends to strip them out.<br />I do not know if this was a market-wide useage of this stuff, but it is on allmost every distributor merc I have seen down here.<br />This stuff is impervious to every solvent I have tried on it, including carbonic carb cleaner.