rpm back down then backfire

sw33ttooth

Chief Petty Officer
Joined
Apr 24, 2011
Messages
498
engine, 5.8l 351 ford
hull, four winns sundowner 225
outdrive, cobra
gas, mid-grade
prop, 15x15, 15x17
max rpm 4k-4,400

my problem,
at wot or 4k+ rpm i can only do about 200 yards and then the rpm drops slowly about 500, then starts to backfire. i then have to return thottle to idle and wait a second then take off again. only happens at 4k+ rpm,.

i put 15 miles on today doing 3800-3900rpm never had an issue temp was running at 175. heading back to the docks i put thottle down 4,300 rpm and then it happend again. the temp was about 180 when i put the thottle back to idle.

did a recent tune up plugs, wires, dist. cap, rotor, set timing, reset ESA was stalling on me, lower unit oil, impellor.

i read a post a while back with an rpm limiter or something on a 454 king cobra i think, obviously not the same engine or outdrive. i just dont know where to start looking. other wise is there an idiot switch for the temp incase its because it shoots up to 180?
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,573
Re: rpm back down then backfire

Ayuh,... Check, 'n change the fuel filters...

Next stop would be a carb rebuild...
 

sw33ttooth

Chief Petty Officer
Joined
Apr 24, 2011
Messages
498
Re: rpm back down then backfire

forgot to post that i changed fuel filter las fall and i know the vent is clean i have gas coming out of it when i top it off, guess it doesnt hurt to spend a few more dollars and replace it again. also just added a new accelerator pump so the inline fuel filter is free of debre as well. had this problem before and after the accelerator pump.
 
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