Boat; 1986 chris craft 17.5 bowrider cavalier, merc 3.0 130hp, 181ci with mercarb 2 bbl (has 1 idle mix adj screw)
just got done summerizing and changed the plugs/cap/rotor/wires (not points) and got it started without much trouble.
However, the same thing happened as what did in end of the season last year (which i thought was bad gas but never got it running right and winterized it.)
It starts, warm or cold, but stalls in about 10 seconds, unless i gas it hard and then it surges up in rpm and has a hard time maintaining the rpm and slowly goes down. if i decrease the rpm from 3k or so, it goes down into a stall. then restarting is a pia, and it does the same thing. ironically, it started, idled and powered up and down (from 1000rpm idle to 4500 rpm)perfectly several times today. the problems are erratic. sometimes idle is smooth and perfect, other times hiccuping. Over 1700 rpm though it consistently seems to stumble and decreases rpm slowly until stalling out. if given gas while slowing, it either catches and surges, or just continues to stall out. it did afew times today, but overall cannot hold a steady rpm over 2000.
i checked for vacuumm leaks with carb cleaner and none found, tightened the carb down for good measure, checked the elec choke and idle mix screw - all good. accelerator pump seems to be shooting fuel fine and fuel pump seems to pressurize the lines pretty well (though not tested with pressure guage).
I thoguht bad fuel. but it was starbrite treated last year and again today with about 4 gal of fresh fuel. i cleaned the fuel filter in the carb - it was dirty and i cleaned and replaced it. i removed the filter from the bottom of the fuel pump - it was almost in there sideways and really deteriorated- i took it out and this incredibly made no differences. also put new fuel water sperator.
I am going to change the points, replace the ignition coil as i have read that could be culprit and maybe run it from an auxillary tank with new fuel line just to test it.
possible fixes?: drain tank/fresh gas, new fuel lines, carb rebuild, electronic ignition system. i did not do a compression test.
any help or input would be appreciated, thanks, Vince
just got done summerizing and changed the plugs/cap/rotor/wires (not points) and got it started without much trouble.
However, the same thing happened as what did in end of the season last year (which i thought was bad gas but never got it running right and winterized it.)
It starts, warm or cold, but stalls in about 10 seconds, unless i gas it hard and then it surges up in rpm and has a hard time maintaining the rpm and slowly goes down. if i decrease the rpm from 3k or so, it goes down into a stall. then restarting is a pia, and it does the same thing. ironically, it started, idled and powered up and down (from 1000rpm idle to 4500 rpm)perfectly several times today. the problems are erratic. sometimes idle is smooth and perfect, other times hiccuping. Over 1700 rpm though it consistently seems to stumble and decreases rpm slowly until stalling out. if given gas while slowing, it either catches and surges, or just continues to stall out. it did afew times today, but overall cannot hold a steady rpm over 2000.
i checked for vacuumm leaks with carb cleaner and none found, tightened the carb down for good measure, checked the elec choke and idle mix screw - all good. accelerator pump seems to be shooting fuel fine and fuel pump seems to pressurize the lines pretty well (though not tested with pressure guage).
I thoguht bad fuel. but it was starbrite treated last year and again today with about 4 gal of fresh fuel. i cleaned the fuel filter in the carb - it was dirty and i cleaned and replaced it. i removed the filter from the bottom of the fuel pump - it was almost in there sideways and really deteriorated- i took it out and this incredibly made no differences. also put new fuel water sperator.
I am going to change the points, replace the ignition coil as i have read that could be culprit and maybe run it from an auxillary tank with new fuel line just to test it.
possible fixes?: drain tank/fresh gas, new fuel lines, carb rebuild, electronic ignition system. i did not do a compression test.
any help or input would be appreciated, thanks, Vince
