1993 Evinrude 9.9 misses at high RPM: Powerpack??

Hello all,

I have a 9.9 Evinrude model E10RELETM that runs rough and develops little or no power at high RPM (high throttle setting). It seems to idle fine and run smooth at lower power settings. It also seems to run best when we first take the boat out. It won't miss or bog down at all for the first few minutes (although, I don't think it develops the power it should), but then does not run well for the rest of the day.The motor is new to me and has had this problem since I got it, so I don't know what the normal idle and power capacity is supposed to be. I asked about it in another thread I posted about another topic and was given some good advise on checking the carb. Before I got to the carb, I wanted to test the spark.

I removed the bottom plug wire and started the engine (using muffs at home) and it ran as it always does out of the water. I tried the same with the top plug removed, using only the bottom cylinder. It would not start. I assumed that the engine was running on only one cylinder. I plugged both back in and started it again. While running, I removed the bottom plug and it ran rougher, but not as bad as when the top plug is removed. The bottom plug seems to be weak, but is providing some spark (maybe both are weak, but the bottom is just worse?). It also seems to smoke a lot when first started. Could this be the power pack or coils or both? Is there anyway to determine the problem without diagnostic tools that I do not posses?

Here is a video of the engine running in the water when warmed up:
http://www.youtube.com/watch?v=_9XyqKDM79c&feature=youtu.be

Any info or advise is appreciated.
Thanks,
Bill

Make up something to test the spark intensity !----Laying plugs on the block is not a good test.---See if spark will jump a gap of 7/16" on both leads.

Racerone is right.

Also when the spark occurs. Is it a muffled, sort of quiet, orangy like color ? ...... Or is it a blue / white, thin line, intense color, with a sharp snappy sound.

Compare the arc of the plug gap laying on a VERY CLEAN METAL part of the block. You MUST MUST pin down the plug during the arcing !!!!....Get another person to crank over the engine.

ABOVE ALL ELSE !!......Do NOT remove both plugs at the same time & leave either 1 not FULLY grounded or swing in the air !! That can cause SUPER HIGH voltages that can / will damage perfectly good ignition parts. Do 1 plug COMPLETLY at a time..........

Both with a cold , first starting of the engine and later when it is running badly. Do both spark plugs to see if both are the same type of arc.

We want to find out if the arc is different in color & sound. Hot or cold. Top or bottom plug.

My gut feeling is the very beginning of a ignition problem getting worse over time.

Have you removed each spark plug & looked at the white insulator for the condition of it ? Really ugly black, thick coating. Light brown color. Almost white. White with blisters on it. Center metal or the ground electrode started to be eaten up ?

cyclops2 said:

Racerone is right.

Also when the spark occurs. Is it a muffled, sort of quiet, orangy like color ? ...... Or is it a blue / white, thin line, intense color, with a sharp snappy sound.

Compare the arc of the plug gap laying on a VERY CLEAN METAL part of the block. You MUST MUST pin down the plug during the arcing !!!!....Get another person to crank over the engine.

ABOVE ALL ELSE !!......Do NOT remove both plugs at the same time & leave either 1 not FULLY grounded or swing in the air !! That can cause SUPER HIGH voltages that can / will damage perfectly good ignition parts. Do 1 plug COMPLETLY at a time..........

Both with a cold , first starting of the engine and later when it is running badly. Do both spark plugs to see if both are the same type of arc.

We want to find out if the arc is different in color & sound. Hot or cold. Top or bottom plug.

My gut feeling is the very beginning of a ignition problem getting worse over time.

Click to expand...

Ok, thanks. I didn't have any luck getting a spark when I tried this before. I don't think I could find a good place on the block within the reach of the spark plug wire. Maybe a should just get a spark plug tester and try that. When I tested before, it was one plug at a time, but thanks for being clear about the danger of having both plugs out.

If the spark is not strong or had weak color, would that be a coil, power pack or wire? Or maybe a combination of both?

cyclops2 said:

Have you removed each spark plug & looked at the white insulator for the condition of it ? Really ugly black, thick coating. Light brown color. Almost white. White with blisters on it. Center metal or the ground electrode started to be eaten up ?

Click to expand...

The plugs are brand new Champion QL77JC4's, but I will take a look at them again to see if any patterns have developed in the few times I have used them.
Thanks

I didn't have time to check the spark today, but I just checked to see if I could see any loose wires, etc. I made sure the spark plug wires were secure on the coil end. I took it out and it ran very well. I figured that I must have found a loose wire or something and inadvertently solved the problem. After 20 minutes of running, it started acting up again. It seems that whenever the engine gets warm, it runs worse (today was a cool day). Does this warm engine problem sound like a power pack or coil problem to anyone?
Thanks,
Bill

I tested the spark. The top plug will spark at about 1/2 inch. The bottom will only do about 1/4 inch. Obviously, the bottom is weak. Would this be a bad coil or power pack?