stupid ????

[biggs-cj]

well got a 351 m that doesent like to run anymore? it idles fine but when you give it gas it likes to back fire out the tail pipe and the carb.....checked the timeing, plugs ,wireing,and checked for air leaks around the carb ,nothing seems to be wrong,,,,,its got me baffled???????????anyone got something i missed????????

[fr3db3ar]

if it's backfiring like that it has to either be timing or a sticky valve. Double check the firing order just to be sure.

[bigblue2230]

does it have any aftermarket parts on it? I had a 351m in my trucvk before with a crane cam in it, and the new cam walked forward and chewed up the distributer gear, which made it run like crap and finally die. just something worth checking.

[Yetti]

well if it helps to know I used to be a engine repair guy at the dealer. the back firing could be a couple of things. if its a stuck valve or bad guide then it will pop with every cycle of the ignition, as the engine speeds up the pop would speed up. if its a cam problem or a junk lifter it would build up and then go wild poping very fast at medium to high rpms. hope you get it sorted out.

[biggs-cj]

Originally Posted by Yetti

well if it helps to know I used to be a engine repair guy at the dealer. the back firing could be a couple of things. if its a stuck valve or bad guide then it will pop with every cycle of the ignition, as the engine speeds up the pop would speed up. if its a cam problem or a junk lifter it would build up and then go wild poping very fast at medium to high rpms. hope you get it sorted out.

thats the only thing i havent checked,its been sitting for a couple years,so it probly is sticky valves......it ran great before,donsent back fire at idle onle when you give it more gas,,,,have to check this out ....thanks

[Mclovin]

Check your carb setting, Could just be you have the high RPM needle too rich.. I dont know much about carbs but i beleive they have a high RPM needle and a Low one

[SageJp]

If I had to guess, I'd say it sounds like a stretch out timing chain.
I've had 2 engines with stretched timing chains and both ran the way yours is.

[biggs-cj]

Originally Posted by SageJp

If I had to guess, I'd say it sounds like a stretch out timing chain.
I've had 2 engines with stretched timing chains and both ran the way yours is.

i was thinking that today.......going to check it out this weekend....do for a new one anyways

[biggs-cj]

Originally Posted by Muddinguy

Check your carb setting, Could just be you have the high RPM needle too rich.. I dont know much about carbs but i beleive they have a high RPM needle and a Low one

?they have a air and fuel mixture but never herd of a high an low needle valve???thanks though

[DeltaCavXJ]

my olds is doing the same thing i think its a sticky valve but im not sure either