Still having problems - 115HP Mercury Blueband

[johnno]

Hi,<br /><br />The intermittent problem with my 115HP 1979 Mercury Blueband continues. Thanks to everyone who has provided advice to date.<br /><br />Symptoms<br />Intermittent misfiring and won't idle. Sometimes the motor works fine though.<br /><br />To date, I have completely drained the fuel tank and filled with fresh fuel and cleaned the carbies (all three). I thought the problem was fixed after changing all of the spark plugs but after a recent trip the problem reappeared.<br /><br />It also seems to occur only when the motor has warmed up. When misfiring the temperature of the tell tale water seems to be hotter than normal.<br /><br />Apologies for the long message, but I wanted to include as much information as possible.<br /><br />Thanks in advance for any assistance.

 

[Rex]

Re: Still having problems - 115HP Mercury Blueband

WHEN YOUR ENGINE WARMS UP THE ELECTRONIC<br />IGNITION STSTEM IS STARTING TO FAIL.<br /><br />YOU NEED TO CHECK IN AT "MARINEPARTS.COM"<br />GO TO MERCURY TROUBLSHOOTING.<br />THEN GO TO "OUTBOARDPARTS.COM" THEY ARE THE<br />BEST.<br />JUST LET ME KNOW WHAT YOU FIND.<br />WHAT GETS THE MOST HEAT? THAT WHERE I WOULD <br />START.<br />THE TRIGGER STATOR SWITCH BOX RECT/REG.<br />DO YOU KNOW WHAT PLUG ARE MISSING.<br />TAKE IT OUT AND RUN IT ON HIGH UNTIL IT STARTS TO MISS THEN SHUT THE ENGINE OFF<br />RIGHT THEN.<br />PULL THE PLUG TO SEE WHAT ONES IT IS.<br />IF IT ONLY THREE THAT COME FROM THE SAME<br />SWITCH BOX DO THE SAME AFTER YOU CHANGE THE<br />WIRE FORM ONE TO THE OTHER AND RUN IT AGAIN.<br />AND DO THE SAME THING IF IT THE OTHER PLUGS<br />THEN I WOULD SAY IT THE SWITCH BOX THAT STARTING TO GET WEAK.<br />REX A HUBBLE<br />E-MAIL hubb1925@yahoo.com<br />GOOD LUCK

 

[ODDD1]

Re: Still having problems - 115HP Mercury Blueband

Johnno, dont overlook a possible water leak in the exhaust chest...I have seen this problem come from a failed gasket in the exhaust........after a period of low rpm use, pull out the plugs and see if they show any water [small droplets or just a oily/milky slime on the end of the plug] usually the lower 3 cylinders are the ones affected...motor will generally run well in upper rpm's but only show this prob at idle.....I am not saying this is what is wrong, but it is not something you want to overlook...

 

[Liam]

Re: Still having problems - 115HP Mercury Blueband

I agree with Rex. I had a similar problem with my Johnson 50. Went completely through the fuel system with no change. Turned out to be a bad powerpack. When it heated up it stopped working. The motor would run beautifully under load and bog down if I tried to go anywhere.<br /><br />Good Luck

 

[Liam]

Re: Still having problems - 115HP Mercury Blueband

Sorry - should say under no load

 

[johnno]

Re: Still having problems - 115HP Mercury Blueband

Hi All,<br /><br />Thanks for your replies and advice.<br /><br />Just to let everyone know that I found the contact in coil #2 where it accepts the spark plug cable) totally eaten/corroded away causing an open circuit condition to the spark plug.<br /><br />Took a run down to the second hand boat motor parts place, a picked one up and replaced.<br /><br />It nows idles well (even after warmed up). Another test on the water in the next couple of days. I think the problem is finally nailed.<br /><br />Thanks again for your assistance.