Suzuki DT40 rough idle

[dheiert]

My brother bought a Boston WHaler withe the DT40 on it last year. It runs great around 4800, but the idel is rough as a cob.<br /><br />Any ideas? BTW, what is the gap on the plugs and what should he buy to replace them?<br /><br />Thanks!

 

[jafa]

Re: Suzuki DT40 rough idle

Hi David<br />NGK B8HS set at 0.8-09 mm by the book. Use BR8HS if you need suppressors , I'm currently useing BR7HS's set to 1mm to overcome an oil fouling problem , the lower the number on ngk's the hotter the plug temp (opp of champ plugs).<br />As for rough running , I gotta say my lawnmower runs wayyy smoother , it misses, pops, vibrates. Stripped down the carbs soaked all the parts in carb cleaner and blew compressed air through all the carb holes and it made no difference at all to the rough idle. It did improve pickup and mpg. Gonna pump a can of decarb spray through iy next week. Manual recomends a decarb after every 50 hours of use. 95/92 psi cold 120/130 warm.

 

[dheiert]

Re: Suzuki DT40 rough idle

Thanks rockhopper!<br /><br />That is a lot of good info and I am glad to know that someone else has the same rough idle..<br /><br />The motor seems to run fine when you tach it up some so I guess it is nothing strange...