need WOT troubleshooting help

[hoot]

250 cu. in. IL6 w/ carb & points, normally runs 4200 to 4600 rpm. last trip out only reached 3600 rpm with skipping and missing in motor. timing is ok with advance working, new plugs installed, points and condensor have 1 season on them, gapped ok. boat starts and idles fine, accelerates up to 3600 rpms good, but no more . motor with muffs only went to 3600. cleaned screen at carb, no luck. suggestions welcomed.

 

[daveswaves]

Re: need WOT troubleshooting help

Hoot, if it runs smoothly up to 3600 and then starts missing I would guess a small speck of dirt in the high speed jet, just enough to lean it out. The other thing it could be is "tracking" in the dist cap, the spark jumps to the wrong plug and you get your miss and lower rpm.

 

[akriverrat]

Re: need WOT troubleshooting help

too wide a point gap or weak spring can cause points to "float".i've seen that a couple of times.

 

[echozulu]

Re: need WOT troubleshooting help

are you running the engine that fast on earmuffs ???

 

[hoot]

Re: need WOT troubleshooting help

only rev up for a very short period of time, less than 3 seconds. keep eye on water temp. replaced fuel filter, points, cond., plugs are fouled. looking at carb next.