115hp mercury 1999 4 cyl inline no fire on 2 cyl

[achris]

Re: 115hp mercury 1999 4 cyl inline no fire on 2 cyl

I know its spark issue not fuel issue ..it run on choke cause it feed the bottom carb and I think the bottom carb doesn't have any idlel jet .....it doesn't spark on 2 top cylinder It seem those engine run on the top cylinder at idle ...

Absolutely correct...

 

[modsrx]

Re: 115hp mercury 1999 4 cyl inline no fire on 2 cyl

Absolutely correct...

thnx for the help guys ...sounds like the coil number 3 was bad ...unplug #3 and everything work perfect ...so I order a brand new coil ....big thnx again

 

[modsrx]

Re: 115hp mercury 1999 4 cyl inline no fire on 2 cyl

i change the #3 coil not i got very nice good spark on cylinder 1 and 2and the motor runs good outside of water ...question now is the 3 and 4 spark is weak now vs the #1 and 2 is it normal ?? running outside water on a hose idling ??..ill go do a test this weekend but was not sure if its was normal ..i know its a 2+2 motor .

 

[CharlieB]

Re: 115hp mercury 1999 4 cyl inline no fire on 2 cyl

A spark test using a 7/16 inch gap in free air is the determining factor, any less and the spark may not fire at WOT under load.

You could hold the wire 7/16 from the block and have a helper crank it, or rig a holder so you can't get bit, either way you want that 7/16 gap so you can see and hear that nice fat blue arc, test every coil in the same manner, all should have the same arc.

Edit Check out this DIY Spark tester, use your imagination.

http://forums.iboats.com/showthread.php?t=526087&highlight=Joe+Reeves+Spark+Tester

 

[modsrx]

Re: 115hp mercury 1999 4 cyl inline no fire on 2 cyl

A spark test using a 7/16 inch gap in free air is the determining factor, any less and the spark may not fire at WOT under load.

You could hold the wire 7/16 from the block and have a helper crank it, or rig a holder so you can't get bit, either way you want that 7/16 gap so you can see and hear that nice fat blue arc, test every coil in the same manner, all should have the same arc.

Edit Check out this DIY Spark tester, use your imagination.

Spark tester?/ 526087

the things is that the spark was very good on the cylinder 3 and 4 and no spark on cyl 1 and 2 so per the advice i found that the coil on the cylinder 3 was bad..so change the coil on the number 3 and now i got very good spark on the number 1 and 2 but the spark on coil 3 and 4 is weak now but it was not that way before ...is it normal cause its a 2+2 motor ..im a little lost ..it can't be the coil its brand new ...i try to unhook the coil number 1 and 2 and still the same spark its not good

 

[CharlieB]

Re: 115hp mercury 1999 4 cyl inline no fire on 2 cyl

Are you using a measured gap or just looking at the spark. The human eye can be a poor measuring tool, if the spark arcs across the measured gap the motor will perform.

Check ground connections, Each must be clean and tight, if the surface any terminal contacts is painted, then scratch or sand it clean.

 

[modsrx]

Re: 115hp mercury 1999 4 cyl inline no fire on 2 cyl

Are you using a measured gap or just looking at the spark. The human eye can be a poor measuring tool, if the spark arcs across the measured gap the motor will perform.

Check ground connections, Each must be clean and tight, if the surface any terminal contacts is painted, then scratch or sand it clean.

only with eyes its not hard to see the difference ....big blue spark vs almost not visible spark ..but before i change the coil the cylinder 3 and 4 the spark was perfect and blue

 

[CharlieB]

Re: 115hp mercury 1999 4 cyl inline no fire on 2 cyl

Have you switched 3 & 4 with 1 & 2 to see if the spark seems to move with the coils?

If it does not change position then I suggest DVA testing the stator pins at every coil, write down the readings. This may be where a digital peak reading meter with a DVA adaptor can have the advantage, much more precise readings than reading an analog needle swing.

I may be possible for the stator to be loosing insulation on a few windings so output to a specific coil is reduced.

Because of that NO RETURN on electrical parts you need to properly test and PROVE any fault rather than start throwing expensive non-returnable parts at your motor.

Edit; I cut a paper clip and wound an eye on one end of the pieces. This makes a pin I can stick into the socket and attach my meter to.