Engine Surge at WOT

Well I checked out the cap and its looks pretty clean underneath, however the rotor mechanisms look a little rough or used. Should I take some emery cloth and rub under the cap and anywhere else? One thing I did not mention before is when I was adjusting the pickup to the fins on the top of distributor, I had to bump the key to get the fins aligned with the pick up. When doing so, there was some sparking or arcing coming from the coil area. I cant really say where, I just heard a sparking noise. Turned key again, and it looked like it was from the bracket holding the coil in place. I turned the key a few times after and it didnt do it again. If I do go with a new coil, MSD has a couple options and would like to know which one is the correct one for my application. My coil says use with external resistor, I do not know what this is, should I replace cap also while I'm at it? Here are the two I am looking at. Hopefully one of these is the right choice, If not, what should I go with. Thanks again


MSD Ignition 8223 - MSD Blaster Coil Details

Blaster 3 Coils

Coil Specs:

Turns ratio: 100:1
Primary resistance: .7 OHMs
Secondary resistance: 4.5K OHMs
Inductance: 8 mH
Maximum voltage: 45,000 Volts (Tested with 6AL Ignition)
Peak current: 140 mA
Spark duration: 350 uS

Features:

Extra tall secondary tower for secure coil wire connection
Improved output coil for electronic ignitions, and MSD Ignitions (ballast resistor required for points)
100:1 turns ratio and lower primary resistance produce high voltage output
MSD Red metal canister is filled with a premium grade oil for cooling
Supplied with a 90° spark plug style terminal and boot
CARB E.O. Approved

or

High-Vibration Blaster Coils

In applications such as off-road, marine or other harsh conditions, the MSD Blaster High Vibration Coil is the best choice. The sturdy metal housing of the High Vibration Coil is completely pot­ted with a premium grade epoxy to completely encase the coil's primary and secondary windings. This protects the coil's internal components from high and low frequency vibrations that are commonly experienced in racing.

Coil Specs:

Turns ratio: 100:1
Primary resistance: .7 OHMs
Secondary resistance: 4.5K OHMs
Inductance: 8 mH
Maximum voltage: 45,000 Volts (Tested with 6AL Ignition)
Peak current: 140 mA
Spark duration: 350 uS

Features:

Improved output coil for electronic, Point, Blaster or MSD 5, 6, and 7 Series Ignitions (ballast resistor required for points)
Alkyd tower with high dielectric properties is less prone to carbon tracking
100:1 turns ratio and lower primary resistance produce high voltage output
Metal canister is encased with epoxy to protect the windings from high vibration applications
50 State Legal
CARB Legal for OBDII 2003 or Older E.O. D-40-37

Anyway, here a few pics.

Levin - I have the same Prestolite EI as you, using the High Vibe coil without resistor. Has worked good for 4+ years.

levinmark wrote: ...One thing I did not mention before is when I was adjusting the pickup to the fins on the top of distributor, I had to bump the key to get the fins aligned with the pick up. When doing so, there was some sparking or arcing coming from the coil area. I cant really say where, I just heard a sparking noise. Turned key again, and it looked like it was from the bracket holding the coil in place. I turned the key a few times after and it didnt do it again...

Could be that the body/case of the coil is breaking down allowing spark to leak to the engine block. I saw that happen with a VW one time.

I got 8mm for mine. At the time, they were colored yellow (still are on my boat). The same kit on Nautiqueparts is black now. It looks like skidim has an upgraded low resistance 8mm set in blue.

8 is already an upgrade from the 7. Not sure if you'd need to step it up further than that. Maybe for an upgraded ignition or something.

Thanks for the replies guys, Do you think my wires are fine, they are PCM wires only three years old and what plugs and gap would you reccomend running? Hopefully wires are ok for now and Ill hit napa for some plugs. Thanks again for the help, Ill let you know how she runs this weekend

As long as the wires are good (and have no spots where the insulation has worn through) 3 years isn't that old.

These are kind of nice to have, as they help keep the wires off stuff that is hot and/or rotates:
http://www.summitracing.com/parts/maa-9-28150/overview/
You could make use of two sets.

Thanks again for he input guys, Ill pull the plugs tomorrow after work and see how they are, I'll keep you informed on how the weekend goes

That's good to hear. And, it sounds like most of the other items that were checked/adjusted/replaced along the way were maintenance items anyway. Glad you got it solved

I would find a valid test procedure before changing any parts. Maybe towing another boat would provide the load to make it act up. Then you can be sure that you definitely fixed it.

My guess is weak spark.

This might be worth a try - I bet others will post their recommendation too:

tester

Do you have any play in the distributor? Like if you take the cap off and try and wobble the shaft by holding the rotor, is there much movement there?

Not sure if anyone mentioned the choke. I was reading the manual on the Holley 4160 on our 84 SN2001, and it says to make sure the electric choke is attached to the basic 12V system and not to the ignition or coil, which would reduce voltage and not open the choke completely and also impair ignition firing efficiency.

Another long shot - is the flame arrestor clean? If it is clogged up, it could restrict airflow.

I believe you still have a fuel flow issue, not electrical.

Recommend diassembling the tank's dip tube and fittings.

Hey, whatever it takes to fix this dang issue! Ill check the choke plate and see what happens when I turn the key. Plan on headn to the quarry tomorrow after work, Ill be in touch with my findings. Thanks again for the guidance fellas!