No spark, Merc 255MIE

[legoman67]

I was trying the second engine for our boat and we discovered that we arent getting any spark at the plug. The coil is perfect, and is getting direct 12 volts from the battery, distributer is super clean inside and looks new. and there is 0 resistance between the distributer base and the negative battery terminal. Please help, i have no idea what to try next.

1979 Merc 255MIE

 

[NoKlu]

Re: No spark, Merc 255MIE

If it's an electronic distributor the module in it might be no good. If you have points you can open and close them with a screw driver and the key on and check for spark. No spark, change the points and condenser.

 

[legoman67]

Re: No spark, Merc 255MIE

its possible i guess, but like i said the thing looks brand new inside. it would be hard to believe something in there isnt right. Its a newer mallory distributor. I will try that tomorrow as its dark now and we have put everything away for the night

 

[gypsysoul]

Re: No spark, Merc 255MIE

matt
is the the coil a mallory? and is the dist. electronic or points type? some ignition systems have to use a resistor because they don't run actual 12 volts usually about 9. they will run twelve to start because the draw from the starter will knock the voltage down during the staring cycle. most newer coils have the resistor built in, but not always.

 

[legoman67]

Re: No spark, Merc 255MIE

hey, it should all be fine in that aspect, it is the identical twin to the other engine, which runs great....

 

[gypsysoul]

Re: No spark, Merc 255MIE

Is it points type distributor?

 

[legoman67]

Re: No spark, Merc 255MIE

yes it is, everything inside is very shiny and new looking, this is very odd, we already tried swapping coils with the other engine that runs and that didnt do it...

 

[gypsysoul]

Re: No spark, Merc 255MIE

ok, you say you have no spark at the plugs, are we checking the coil wire going to the dist. to see if it has spark? I have seen caps that go bad and won't let spark get in to the rotor. also with the cap off and the power to the coil bump the engine until the points are open. then use a screwdrive to ground beetween the contacts on the points and see if the coil wire fires. have the coil wire about half a inch from something metal like the intake manifold. and see if spark jumps from wire to manifold

 

[legoman67]

Re: No spark, Merc 255MIE

ill give that a shot tomorrow and get back to you. Thanks

 

[gypsysoul]

Re: No spark, Merc 255MIE

good luck I will keep a ear out for ya, yak at ya latter I am going to bed.

 

[legoman67]

Re: No spark, Merc 255MIE

got it, i pulled all the other wires off the coil and had a spark plug out testing for spark and then VROOOOM, it fired right up, no throttle, no priming, 1 sparkplug short. poped the plug back in, primed it and VROOM. runs good now, now i need to figure out where the short is in the wires i pulled off the coil..

thanks

 

[gypsysoul]

Re: No spark, Merc 255MIE

maybe a tach wire? if it is not in the boat what was all the other wires on there? does not really matter it runs and that is the important part. glad you found the problem

 

[legoman67]

Re: No spark, Merc 255MIE

not sure what it was, it was on the ground that i ran it.. i found the other end cut off touching the block, so that was the problem... referenced to the wiring diagram and its non existance(tach wire acounted for), so probably something the previous boat the engines were in had..

engines should be going in the boat this saturday

 

[gypsysoul]

Re: No spark, Merc 255MIE

can't wait to see them in and hooked up, good luck yak at ya latter!