bog at full throttle

« **on:** September 04, 2015, 12:04:45 AM »

So i have a 455 olds that has tunnel ran 850 demon carb when i hit full theottle i have a bog at very top of throttle can let off a lil and it will start pulling and thpught it was to rich down aized jet along with pther adjustments made it worse so went back to where it was the least but still has a bog at full throttle im start to think im not getting enough fuel did a full throttle run shut off checked plugs nice light tan color so im confused of what it happening my pne buddy thinks cuz of the runnel ran that i need to go bigger jets and ideas guys

« **Reply #1 on:** September 04, 2015, 01:59:18 AM »

Ill get the ball rolling..im sure we'll have some better advice soon but its late and im bored! Lol
1.. does the carb have jet extentions on the secondary side?
2.. are the floats set correctly?
3..what fuel system are you running?
4.. whats the fuel pressure at w.o.t?
5..what ignition are you running?
6.. whats your total ignition timing?..
Just a few places to start.. we were just fighting with my buddys boat fallin over at w.o.t.. with a single carb tunnel ram on it..was acting like it was lean..we kept throwing jet at it... put a pertronix in the distributor and it went away..... im also a firm believer that alil fat on the jet sizing is way better than alil lean... good luck sir..

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« **Reply #2 on:** September 04, 2015, 12:47:28 PM »

Im running full msd 6al dizzy coil blaster the 6al is new wires are new dizzy cap and rotar are what was on boat when i gpt it before i put tunnel ram on motor i did not have the bog found out one of my secondarie jets was not in meterimg block anymore so put it back motor is fresh rebuild at begining of season i have thought about maybe the dizzy is bad but i have my advanced set at 34 degrees it does not have extended secondaries so what you did to the dizzy fixed your buddys prob

« **Reply #3 on:** September 04, 2015, 12:51:17 PM »

You think it be worth trying to up size my jets i already thought it was to fat and went down it just got worse so went back to what i ha e in it now if ao just do the secondaries or primary also

« **Reply #4 on:** September 04, 2015, 02:29:24 PM »

What jets are in it?

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« **Reply #5 on:** September 04, 2015, 03:12:21 PM »

I had the same problem on my last motor for out is was my HEI distributor. Replaced with a new MSD HEI and it never did it again.

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« **Reply #6 on:** September 04, 2015, 10:12:51 PM »

I have 87 in primary and 94s in secondaries im running full msd

« **Reply #7 on:** September 09, 2015, 07:58:09 AM »

What's your cam profile and was it degreed in? Compression? How many hours on the timing chain? Oldsmobile's have a heavy valve train to roll over, stretch in the chain can result in your symptom also, due to cam retard.

aquatic kuruption

bog at full throttle

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