puder

i have a Merc Thunderbolt4 ignition with a v6 module. It give me 24* initial timing and full should be in by 3500. I have an MSD box (was told it will run better with it) and a blaster coil.

puder

TTT

NASTY HABIT

good to see you are on your way to getting that thing done

boot

Hey Puder congrats !

What carb are you running ? More fuel (richer air fuel ratio) can cool things down some .

Good luck with it .

DanL

EGT's are too hot. Just suppose you are running a light load of fuel and you turn hard and unload the fuel pickup. You'll hole a piston. Whats the fuel pressure? Maybe half a main jet up in the front of the carb. 1400 is about 50 too hot. you need 1200+ to burn deposits off of the electrode. If the electrode on the plug gets too hot, it glows and its all over. Go down one heat range on the plug,up a little on the main jets. Bruce will know what to do.

puder

soem more input like dan's woudl be great!!!!

thanks all!!!!

Griff

I think DanL's on the right track. Looks like a slight fuel distribution problem that happens with single carb blowers on BB's. #1 and #2 are the farthest away and are the hottest. I like DanL's advice of a cooler plug and jetting up the front. More than likely, it's going to need some fine tuning in the boat also as the amount of load on the engine will vary somewhat compared to the dyno. I don't think 33* timing will be a problem. My 525sc has 12* initial with a 22* module.

puder

you were running 34* total??? Was that how merc set it up?

Biggus

iTrader: (1)

The reason behind the 525SC running 35 deg total is because the 525 has 7.5 to 1 compression ratio and can get away with more timing with out detonation.

Puder, if you want the motor to live, no more than 30 deg.

Trust me, I`ve blown up MANY motors and have learned the hard way.

DanL, you are right on the money, good call

Kurt.

cobra marty

By your A/F numbers your 10's and 11's are a little rich and the 13 a little lean. Need to lean out the midrange and slightly fatten the top end.