suzuki dt25 erratic idle and start

[top doggie]

1996dt25 suzuki.this motor runs fine one day the next it doesn,t want to idle or start properly.had carbs done.replaced all fuel lines and fittings.goes fine wot just not at idle,sometimes sneezes before stalling.could this be a fuel pump problem or a coil or something?mixture screws on carbs at 1.5 turns out.i dont think lean sneeze is the problem.maybe electrical?also it seems to be surging

 

[rodbolt]

Re: suzuki dt25 erratic idle and start

most likly its still a fuelk issue. thats the only thing that causes the sneeze.<br /> that sneeze is actually the next fuel charge but its burning on the wrong side of the piston. as it cannot escape the crankcase it coughs and tries to push the downward moving piston back up. <br /> some do it so violently it will shear a flywheel key.<br /> based on your description I would continue looking at fuel issues but you can check the ign system.<br /> somnetimes the mixture screws have to be played with.<br /> on most mikuni carbs turning the screw in makes it richer.

 

[top doggie]

Re: suzuki dt25 erratic idle and start

should all screws on carbs be the same setting?i was told this is vital for a smooth idle?motor only seems to run rough and stop at low idle.when idled up a bit it keeps running but is quiet rough,not the normal smooth idle!

 

[rodbolt]

Re: suzuki dt25 erratic idle and start

not all the time.<br /> occasionally we have them all over, used to be we set the air fuel mix with a manometer, set them up for the smoothest idle with a smooth acceleration, thats why they are adjustable.

 

[top doggie]

Re: suzuki dt25 erratic idle and start

have now done carbs 3 times.no matter what we do motor idles great then coughs and stalls.done compresion check, all 3piston ok.the mechanic is stumped.he says could be a crankshaft seal?what else other than fuel could have this effect on this motor.it did get hot once blocked with weed but that was 12 months ago,and has ran fine til this.any ideas appreciated