chopperkell

I have a fresh rebuilt 502. has a pretty big cam and a ton of work done to it. I just put it back in the boat and when I run it has a pretty bad miss. I pulled the plugs and the front 2 plugs ( #1 and #2 ) were super black. I put new plugs in and ran it. right away it was still missing. I only ran it for about 1 minute and pulled the front plugs again and they are crazy black. any ideas on what be be happening? seems weird that it is the front 2 plugs.

I have a 1050 dominator carb with blocked power valve and 93 jets in all four corners. msd box ignition. the motor has has a lot of work done to it. 610hp at the dyno shop.

I tried a Hei distributer to by pass the msd box. still did the same. I also checked spark plugs wires by running it and using my test light to the ground on my battery and poked it through the boot at the cap to cause a misfire. every one cause the idle to drop. so seems to me even though the plugs are black as hell they are sparking....

carb/fuel problem? would head gasket / intake gasket leak cause this?

it does have a dart intake and the carb plain slants forward. could my carb be overflowing fuel to just the front 2 cylinders? the fuel pressure was up to high at first. at 11 psi. it is now at 7 psi. I do have a smaller carb I can try but its a 4150 style and the dominator is a 4500 series. I do have the same dart intake for the 4150. was thinking about swapping intakes and carbs and see what happens?? just looking for any other ideas?

I also after the last run pulled the #2 plug and turned it over a couple time and had someone watch the hole and they said quite a bit off fuel shot out?

mike tkach

iTrader: (3)

first thing i would do is check the float level.if that is not the problem i would take the carb apart to see if something is wrong with it.why did you remove the power valve?doing that is a mistake in my book.

SB

iTrader: (1)

When your engine was dyno'd didn't it have your carb,ignition,and etc on it ? they tune it with wideband or hp levels + spark plug readings ?

Not saying it's your problem, just saying it out loud, the minimum common HP level for using a Dom 1050 is 650hp. Again, just an unwritten rule. you don't really see any 4500 1050's used in strong running motors under that.

what exhaust is on it ? Any pics of it ? dry or wet ? was the 'fuel' that came out of the cylinder possibly water ? Easy to mistake.

chopperkell

I did check the float level. it was fine. I got the carb already done that way from the same guy I bought the motor. he said it was the same type and setup as the dyno... not the same carb though... I have a 850 I had on the motor that blew and it worked great. I was going off what I was being told.


SB--- im not sure of all the testing. I didn't take in he did and sent me the video. I have stainless marine 500hp risers and manifolds dry to the tip. I agree with the size of the carb being to big. it just seems a little weird its just the front 2 cylinders. all the rest of the plugs looked perfect.