No Spark - 71 Johnson V4 100HP

[jerjag]

Tried to fire up and discovered no spark at any of the four plugs....looking for test to determine if coil or powerpack (amplifier) is the problem. Any other thoughts or suggestions is always appreciated.<br />Thank you for your help!<br />Jerry

 

[OBJ]

Re: No Spark - 71 Johnson V4 100HP

First thing to do is verify that you have a solid 12V going to the amp....anything less and you run the risk of damaging the amp.<br /><br />Pull the lead from the coil to the distributor and hold the end of the lead close to a clean engine ground. Have a helper crank the engine. If you have spark here, check distributor. If not, pull the flywheel and distributor. Check the points are not burnt and set at .010. There is a reverse cutoff spring under there to. Make sure it's in good shape and not laying against the reverse cutoff assembly. Check the wiping contacts of the distributor. They have a tendency to burn and pit.<br /><br />Could it be the amp? Yes. But checking this other stuff is a good idea. The amps are very pricey.

 

[REELSPORT]

Re: No Spark - 71 Johnson V4 100HP

I hope you do not have to replace the amp but if you do remember to replace the coil at the same time as a faulty coil can fry a amplifier and also be sure not to use a maintance free battery as they tend to overcharge and that can fry your amplifier also. I had to buy a amp for my 69 55hp rude and I dont think I can post where I got it from but I bought it about $80.00 less than retail and if you are interested email me at phinnant@earthlink.net

 

[Joe Reeves]

Re: No Spark - 71 Johnson V4 100HP

(Battery Capacitance Dischage Powerpack Test)<br />Various OMC Engines - 1968 to 1972)<br />(J. Reeves)<br /><br />Purchase a small 12v bulb at your local automotive parts store (the 12v bulb is to look like a flashlight bulb, not a headlight bulb). Solder two wires to that bulb, one to the side of the bulb (ground), and the other to the positive point. <br /><br />Remove the spark plugs. With the key in the on position, make sure that you have 12v going to the pack at the terminal block (purple wire). Now, connect the ground wire from the bulb to any powerhead ground. Connect the wire from the positive point of that bulb to the powerpack wire that is connected to the coil wire on the terminal board (blue wire). <br /><br />Crank the engine and observe that bulb closely (CLOSELY!). If that bulb glows even the slightest bit, the powerpack is okay. It may be a very dim glow... just so it glows! If it doesn't glow, the pack has failed. <br /><br />Keep in mind, that type powerpack (Battery Capacitance Discharge) demands a top notch battery of at least 70 amp hours. Any less will, in time, cause powerpack failure.