Dark plugs

[Jakob5pennies]

I have a 3.0 4 cyl Merc it's a fors engine and do aloy of trolling engine at idle most of time. The plugs get folued alot why colud I do advance the spark or retard it maybe a different plug for hotter spark? 

[fisherdude]

advancing the timing you end up burning holes in the piston . i would think the motor is getting worn and needs a rebuild . can do a compression test to see where you are at . if it runs fine running out / in how about a kicker 

[JAYRFRED]

Internal combustion engines by design are not meant to idle for long periods of time and are prone to loading up due to combustion inefficiency. It is difficult to design an engine to produce power and efficiency @ 35 MPH and still be able to idle all day. Altering ignition timing or spark plug heat range will only lead to other issues such as overheating. A couple things you might be able to try are:

Make sure that your air cleaner is absolutely pristine. More air equals cleaner combustion.

Make sure you run good clean, fresh gasoline. Cheap gas has more impurities.

Run the engine hard at the end of the day to burn the soot off the spark plugs

If you do not already have an electronic ignition, you may want to look into changing over along with a new ignition coil. This will probably provide a better low RPM spark to enhance combustion.

I have read good things about E3 spark plugs if they make them to fit your engine

hope some of this helps

Happy boating

Jay

 

Edited May 8, 2018 by JAYRFRED

[Jakob5pennies]

Thanks for all the sugestions 

[Knotlost Charters]

Start with high octane gas and E3 plugs and it will help alot maybe enough for what you need. What jarred said is very true, thats why kickers are made different than regular motors.

[Ready or Knot]

Black or dark colored plugs is a sign of a rich fuel condition generally a carburetor issue. Check to be sure that choke is opening all the way.  Check pcv valves , vacuum pull off etc. If it is an engine issue the plugs will generally be oilly on the effected cylinders

[JAYRFRED]

5 hours ago, Ready or Knot said:

Black or dark colored plugs is a sign of a rich fuel condition generally a carburetor issue. Check to be sure that choke is opening all the way.  Check pcv valves , vacuum pull off etc. If it is an engine issue the plugs will generally be oilly on the effected cylinders

Or weak spark

[Xxx]

I have a 3.0 4cyl in my 18’er for around home, and I troll a lot also, at 900rpms I had same issues and also went to electronic ignition made it a bit better but not cost effective at all. I was to the same ordeal about the motors not being designed to run at low rpm’s so I had two trolling bags from my 22fter before I went to a kicker. I hung those on now I’m at 1100-1250rpm’s oil pressure is up and haven’t had an issue since. Burns a little more fuel but not enough to complain about!! Just food for thought....

[Chas0218]

On 5/7/2018 at 11:48 AM, Jakob5pennies said:

I have a 3.0 4 cyl Merc it's a fors engine and do aloy of trolling engine at idle most of time. The plugs get folued alot why colud I do advance the spark or retard it maybe a different plug for hotter spark? 

If it doesn't skip or miss then I doubt it's a spark issue.

 

Adjust the low idle mixture on the carb if possible. Turn in the adjustment 1/8 turn at a time and listen to the engine she will tell you what she wants. If it stalls back it out 1/4 turn and do it again tightening it in in smaller increments. Once she stalls again 1/8 turn out and leave it. Do this in gear at idle. After a few adjustments you'll want to take her up on plane then back her down to idle again. Repeat until she is running good.

Edited May 9, 2018 by Chas0218

[Jakob5pennies]

thanks for all the suggestions we will be out to the lake next thursday staying at the catfish . is there any one out there that you would think could adjust the carb on friday ? as i am horrable at carbs . 

Edited May 10, 2018 by Jakob5pennies
wrong place