mcm 4.3lx hesitation when hard on the throttle

brunolund

Chief Petty Officer
Joined
Jan 26, 2008
Messages
432
so my '96 lund, with a 4.3lx, 4 bbl carter, has a bad hesitation when i hit the throttle. if i bring it up slow and smooth, it is fine, but when i crack it wide open from idle, it seems like i'm killing the ignition.
1. it's not the shift cable. it's new, and this happens with the throttle cable disconnected, and manually bumping the lever on the carb.
2. carb has been rebuilt and accelerator pumps are giving great shot of fuel. tried different settings, no change.
3. has been happening since i put in new engine, new plugs, cap, rotor, wires.
4.happens every time, all the time.on muffs, in lake.
5. seems to be only from idle. if engine is cruising at 2300 or so and i open it up, it goes good.
6 haven't checked timing yet, as my light was driven over and not replaced yet. was set at 8 deg. BTDC,
 

Glastron175

Seaman
Joined
Mar 13, 2010
Messages
71
Re: mcm 4.3lx hesitation when hard on the throttle

I think it may be your timing needs to be advanced. Is 8 deg BTDC what the manual calls for? It sounds a bit much to me. My 3.0L calls for 2 deg ATDC.
 

brunolund

Chief Petty Officer
Joined
Jan 26, 2008
Messages
432
Re: mcm 4.3lx hesitation when hard on the throttle

the manual states 8 degrees before TDC. am going to try resetting the timing, but any other opinions would be welcome.
 
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