I have a ?99 Suzuki dt85 (2-stroke) on a 17? cc that I?ve been slowly bringing back to life.
The latest issue has me really confused as to where to start. Things were running great for maybe 15-20 minutes the other day at about ? throttle (maybe 2700-3000rpm) when it suddenly started banging real bad. I immediately throttled-down and the vibration stopped, and when I throttled up past the bad-spot it ran fine again. Only in the upper-2000?s would it hammer.
I headed right back to the dock, and after 7-8 hours of this (well, it was really maybe only 3-4 minutes, but sure felt like HOURS!), everything smoothed-out again and it ran perfect the rest of the day.
It felt like a car I had many years ago that had broke a few teeth in the rear differential ? when it got to the bad area it would feel like a jack-hammer was pounding on the tranny til the gears slipped into alignment again.
I have 2 fuel filters in parallel with no water in them, use non-ethanol gas, and just replaced the plugs, etc.
I?m stumped. I?ve got to assume it?s a misfire situation of some kind, as I can?t believe a bad tooth in the lower unit would cause it to vibrate that bad ? wouldn?t the prop-to-water transition take up a lot of the energy and smooth it out? Especially since it wasn?t present at idle or WOT (4500+)?
Thoughts or Suggestions?
The latest issue has me really confused as to where to start. Things were running great for maybe 15-20 minutes the other day at about ? throttle (maybe 2700-3000rpm) when it suddenly started banging real bad. I immediately throttled-down and the vibration stopped, and when I throttled up past the bad-spot it ran fine again. Only in the upper-2000?s would it hammer.
I headed right back to the dock, and after 7-8 hours of this (well, it was really maybe only 3-4 minutes, but sure felt like HOURS!), everything smoothed-out again and it ran perfect the rest of the day.
It felt like a car I had many years ago that had broke a few teeth in the rear differential ? when it got to the bad area it would feel like a jack-hammer was pounding on the tranny til the gears slipped into alignment again.
I have 2 fuel filters in parallel with no water in them, use non-ethanol gas, and just replaced the plugs, etc.
I?m stumped. I?ve got to assume it?s a misfire situation of some kind, as I can?t believe a bad tooth in the lower unit would cause it to vibrate that bad ? wouldn?t the prop-to-water transition take up a lot of the energy and smooth it out? Especially since it wasn?t present at idle or WOT (4500+)?
Thoughts or Suggestions?