not firing on bottom 2 cyl's 1975 merc 85hp

[Crupi]

i have a 1975 mecrury 85 hp motor.. i just got the boat been messing around with it today i checked the spark on all 4 cyl's compression seems good but lower 2 cyl not firing if i change the wires around the bottom one will fire..i only changed the one wire but it made it fire.. any ideas r if u need more info let me know iam closer then i was when i started.. i need to add to this all the plug wires on the motor u can pull them right off the copper wires isnt connect to the lead in the cap and also i see the ones that r not fire r arcking all over the out side of the plug

 

[RICKRICK1]

Re: not firing on bottom 2 cyl's 1975 merc 85hp

you need to get new plugs and plug wires with good caps. Check with your local NAPA store for these. You will also need to get a manual on this motor as you will need to remove the distributor cap to install the new wires. Good Luck and get back with the results.

 

[Crupi]

Re: not firing on bottom 2 cyl's 1975 merc 85hp

thanks i was going to replace the wires and cap.. i do have a manual plugs r new. i was told by a freind the power pack was gone but he was just telling me that like a guess i think its to much to guess at lol .. any way i will let u know..<br /> Thanks

 

[Crupi]

Re: not firing on bottom 2 cyl's 1975 merc 85hp

does any one else have any ideas on this one?

 

[aeronutt29]

Re: not firing on bottom 2 cyl's 1975 merc 85hp

If the power pack is bad you won't get fire at all. When mine went out it was like switching off the ignition. If you have arcing outside of the wire then you've waited WAY too long to replace them. If you get a "U-Cut-It" universal kit from NAPA, be sure to get solid core wires. The carbon core resistor wires are good for suppressing RF interference, but not so good for lighting fires in an outboard. If you haven't already priced a new distributor cap I'll warn you to be sitting down when you hear the price!

 

[Crupi]

Re: not firing on bottom 2 cyl's 1975 merc 85hp

pretty expensive for cap seems like most parts r lol .i didnt wait lol i just got the boat and seeen it arching ihope it is the problem to tell u tho the cap looks good its the wires that look bad.. just wish i knew why it wqould spark on outside and not fire the plug?<br /><br />thanks for ur help

 

[aeronutt29]

Re: not firing on bottom 2 cyl's 1975 merc 85hp

Electricity always goes to the path of least resistance. If the insulation on the wire has cracked it's got a lower resistance to jump out the side of the wire and into the engine block. It's the same as expecting a water pipe with a crack in it to carry water to where it's supposed to go. Get those wires replaced before doing anything else and then we'll see how she's running!