around 1990 suzuki dt 40 runs good to full speed then slows by itself

markb2360

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Joined
Jun 19, 2013
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2
my dt40 idles great takes off to full speed with no problem and then just slows to about 18 miles per hour,motor still sounds good with no excessive rpm's.Put it back in neautral and it will go back to full speed with no problem and then will slow to about half speeed by itself ,I cant see anything loose,this is a used motor I bought.this motor runs good and sounds better.
 

stylesabu

Master Chief Petty Officer
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Aug 2, 2009
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849
Re: around 1990 suzuki dt 40 runs good to full speed then slows by itself

does rpm stay the same? yhen try another prop,sounds like prop slip
 

markb2360

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Joined
Jun 19, 2013
Messages
2
Re: around 1990 suzuki dt 40 runs good to full speed then slows by itself

does rpm stay the same? yhen try another prop,sounds like prop slip[/QUOT rpm's go down it is as I am reducing speed myself,when the motor slows by itself to around half speed it sounds completely normal
 

CRLUEDER

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Apr 13, 2014
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1
Re: around 1990 suzuki dt 40 runs good to full speed then slows by itself

my dt40 idles great takes off to full speed with no problem and then just slows to about 18 miles per hour,motor still sounds good with no excessive rpm's.Put it back in neautral and it will go back to full speed with no problem and then will slow to about half speeed by itself ,I cant see anything loose,this is a used motor I bought.this motor runs good and sounds better.

Did you ever resolve this problem. I am having the exact same issue.
 

don diego

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Apr 4, 2013
Messages
23
Re: around 1990 suzuki dt 40 runs good to full speed then slows by itself

Could be fuel supply issue. Is the primer bulb firm when this happens? Fuel filter clean?
 
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