1BIGJIM, I just noticed you have a Pachanga, is yours a 22 or 27?
If 22, if you had RMBuilder make you a cam that is larger I am going to assume you have more power than I do. ( Actives Dyno was 560 something ).
What is your setup?
I am going to work the bottom of mine, add a 2" shorty and get BBlades on the prop ( he does my drag stuff )

Looking for mid 80's

RT

RBT - It may sound trivial, but have you checked the thermostat? If you're engine is running cold it could be the thermostat is passing coolant.

Yes, that was one thing I did check.
But it does make sense that the cooling, specially with the aluminium heads needs to be changed.

RT

Are you running a power valve in the carb? If not, you may want to jet down in the primaries and install a 6.5 PV. If you're running a PV, which one is in there? You may have the wrong PV or it could even been blown and with that cam it's activating the powervalve at idle causing you to foul plugs.

When the engine is at idle take off the flame arrestor and look down into the venturi of the primary. If you see fuel slowly dripping down from the venturi you know you found the problem.

if you really do have 4.5 vacumn at idle in gear and you are idling in gear at 750 rpm or above, then i would recommend a 2.5 power valve and jet accordingly

Please don't rip off the cylinder heads and tear into the engine before looking at the carb..... A lot of which has been posted could be possible but I really doubt it.

Also, what plugs are you running?

I think it's your tune... Just my .02.

Oh I know it is my tune, and the external parts. The motor has perfect leakdown. Mechanically it is perfect.
I am so used to EFI ( I program Merc box's, Race, Optimax and Verado ) and I am too damn young to care about carbs.

RT

EFI get thrown off by temperature flutuations (open loop/closed)...not so much on carbs...

I run 100* water temps all day long with a huffer on top, two carbs, 580 cubes, decent size cam, 30 minute idle out to the ocean etc....and not once have I ever fouled a plug.

It's the setup, whether it be carbs, timing or wrong heat range on the plugs IMHO.

It might not run good, but it sure looks good. Doug

See, I can make a 430hp drag outboard idle at 700 rpm all day, shift gears without stalling and turn 11 100 rpm pass after pass. The only part I cannot compensate electronically is humidity, and that is becasue we cannot run O2 or Lambada due to the oil.
TUNE IS EVERYTHING, I can read plugs..... I just need to know where to go to make them read right!
I figured the cooling, and know that carb is off...... but where and you guys are giving me some ideas!
Thanks