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81 DT 175, idle and starting question


saltcreekknife
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My DT175 has a hard time staying at a constant idle. I checked to see if the cable was caught anywhere. It doesn't change when I move the bars back and forth. The throttle slide has a indention where it hits the throttle adjuster. Could this be causing the problem?

Also it takes a looong time to warm up. It dies at idle until it is good and warmed up. No problem starting. Is this common with the dt175?

Thanks

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My DT175 has a hard time staying at a constant idle. I checked to see if the cable was caught anywhere. It doesn't change when I move the bars back and forth. The throttle slide has a indention where it hits the throttle adjuster. Could this be causing the problem?

Also it takes a looong time to warm up. It dies at idle until it is good and warmed up. No problem starting. Is this common with the dt175?

Thanks

Not a million miles away to be honest. Shouldn't need long to run at idle without choke though. Esp this time of year. Could be a bit lean i suppose. No air leaks around the filter/carb area is there. The reed block is a popular one, go round the joints between the carb and the engine with some wd squirting the joints directly and see if anything changes.

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Adjust the throttle stop screw to achieve an idle. Note the position of the air mixture screw and turn it clockwise until it gently seats, it should be around 1 and 1/2 turns out from this position, Now...did moving the mixture screw affect the engine speed at all, it should really get a bit lumpy as you screw this in.

Edit: In another thread you said the 'o' ring was missing from the mixture screw...so did you replace it? you didnt say!

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Adjust the throttle stop screw to achieve an idle. Note the position of the air mixture screw and turn it clockwise until it gently seats, it should be around 1 and 1/2 turns out from this position, Now...did moving the mixture screw affect the engine speed at all, it should really get a bit lumpy as you screw this in.

Edit: In another thread you said the 'o' ring was missing from the mixture screw...so did you replace it? you didnt say!

Will try your suggestions. I did put an o-ring on the mixture screw. Will let you know what happens. As far as the choke goes, it does not seem to do much. It is the plunger type, and there does not seem to be any replacement parts available. Everything looked OK however when I rebuilt the carb.

Thanks

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The bowl gasket has a hole along the one edge - this is for the passage for fuel to the choke. There is a corresponding hole in the bowl - at the bottom of that hole is an orfice with a teeny tiny hole which delivers fuel to the choke. On my bike the choke wasn't doing anything and that orfice was clogged. I used a thin stiff steel wire to clear the orfice and now the choke works great.

Will try your suggestions. I did put an o-ring on the mixture screw. Will let you know what happens. As far as the choke goes, it does not seem to do much. It is the plunger type, and there does not seem to be any replacement parts available. Everything looked OK however when I rebuilt the carb.

Thanks

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  • 2 weeks later...

Will try cleaning hole. I am at my wits end! It will not start up when cold. I have been out of town for a week, and when I tried to start her up, no luck. It is the same as before. If I take out the spark plug it is soaked with gas. I dry it off, put it back in, and she cranks right up. I am not giving any throttle when I first start. Any thoughts or clues as to what might cause this? Could it be the float? Any help would be greatly appreciated.

I will try cleaning out the choke hole. And I have put an o ring on air screw.

Thank you

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Will try cleaning hole. I am at my wits end! It will not start up when cold. I have been out of town for a week, and when I tried to start her up, no luck. It is the same as before. If I take out the spark plug it is soaked with gas. I dry it off, put it back in, and she cranks right up. I am not giving any throttle when I first start. Any thoughts or clues as to what might cause this? Could it be the float? Any help would be greatly appreciated.

I will try cleaning out the choke hole. And I have put an o ring on air screw.

Thank you

If ya have cleaned up the carb, now put the throtle stop screw and the air mixture screw to there factory settings. This will help starting and from there ya can set them to whatever they need to be at for the engine to run nice and smoth.

If your choke isnt doing anything then it will be hard to start from cold. Shouldnt wet the plug like your saying if the choke is not working. So it could be the float height that is set wrong and this will send to much fuel in and wet the plug. ( i dont know what height your float should be at ).

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If ya have cleaned up the carb, now put the throtle stop screw and the air mixture screw to there factory settings. This will help starting and from there ya can set them to whatever they need to be at for the engine to run nice and smoth.

If your choke isnt doing anything then it will be hard to start from cold. Shouldnt wet the plug like your saying if the choke is not working. So it could be the float height that is set wrong and this will send to much fuel in and wet the plug. ( i dont know what height your float should be at ).

I will check the float bowl height and let you know.

Thanks

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