spark plug wires

[tommymoe2002]

Question? I have a force 120 1996 bayliner trophy 2002. Just got it this winter, my question is the old owner never change the spark plug wires. Should I change them and where do I buy them? Also what type of NGK plugs should I use. Thanks and happy boating..... Tom

 

[glass from the past]

Re: spark plug wires

Welcome aboard,<br /><br />I myself, prefer to do a major tuneup when I buy anything motorized that I didn't buy brand new, car, boat, lawnmower, etc. That way I know where I am starting from if I start to run into problems. Plugs, wires, fuel filter, impellar, lowerend lube should all be changed if the boat hasn't had these things done. Depending on how well the motor runs I would decarb it once also. If you don't have one, get a manual, they will explain correct plugs, gap, routine maintenance, winterizing, etc. Plugs and wires are available here at Iboats, or can be picked up most boating stores. Someone will be along to offer more free advice.

 

[roscoe]

Re: spark plug wires

plugs:<br />Champion L76V or NGK BUZHW<br /><br />Use wire core plug wires from NAPA or marine dealer, they are only about $7 a piece from Mercury.<br /><br />Do not use high resistance automotive plug wires!!<br /><br />In addition to the tips above, put in a new fuelpump diaphram ($10).

 

[glass from the past]

Re: spark plug wires

Hey Roscoe,<br /><br />I know this came up in another forum, (auto VS, marine parts)but what is the difference between auto and marine wires? You mentioned the resistance factor, I am wondering because I just made a set of 8mm wires for my Chrysler using auto wires and brass connectors. Please let me know what you think.

 

[roscoe]

Re: spark plug wires

I'll try to find the post, I think I have it bookmarked. But for now; The ignition system cannot overcome the higher resistance and causes damage to it.<br /><br />(Edit)Here is the info:<br /><br />Excerps of several discussions on using automotive ( high resistance carbon fiber) sparkplug wires on outboards:<br /><br />The motor ran great in a barrel in the driveway.. but when I put it on a boat and put it under load.. it would bog down.... <br /><br />You just described what it does. under a load the spark will breakdown and be weak carbon wires are really for high energy ignition and a magneto will not throw enough voltage.....<br /><br />I took off the automotive wires and measured the resistance to be 340 ohms. The new copper wire plug wires measured 0.3 ohms....<br /><br />Although the magneto on older engines is capable of providing ~30000v, most of the energy is transeferred between the coil and the combustion gasses at ~150v during the arc phase of the spark. So with a wire resistance of 340 ohms, a good portion of the coil's potential ends up as heat. More importantly, the spark's transition into the glow phase is hastened since this is current dependant. Energy dissapated during the glow phase is essentially wasted.<br />So, to answer your question properly, somewhere around 40% of the coil's potential is wasted by using resistance wire, even though it's only 340 ohms!<br /><br />Here is the entire topic:<br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=17;t=034125 <br /><br />I have read other posts where the carbon fiber high resistance plug wires were to blame for:<br />poor performance, damaged powerpacks, coils, magnetos, etc. <br />They just aren't good for your ignition system.

 

[glass from the past]

Re: spark plug wires

Agggghhhhh <br /><br />I am doing a search as soon as this posts, thanks for the quick reply.

 

[roscoe]

Re: spark plug wires

^

 

[glass from the past]

Re: spark plug wires

Just picked up the replacements, sad story though. The boat shop down the street (I won' name names but it starts with W and end with EST MARINE ) had no idea as to what I was talking about. One jacko even suggested there was nothing wrong with auto wires, luckily I had printed the post Roscoe sent and had some technical info on me. (HA - LOL) Wonder how many people they sent down the road with the wrong gear? <br /><br />Thanks again Roscoe <br /><br />Just goes to show ya, read them posts, even if you think you fixed your problem already.