Suzuki DT 30, 2004 Ignition coil

[Polycraft]

Try the spark plug tester, you’ve got nothing to lose. I spent about 30 minutes looking for a service manual for your engine on Google and only found one other person looking for a DT 30 2004. All the DT 30 manuals I found stop at 1997, likely a North American thing. If your still in Australia I’d stop into a Suzuki dealer and inquire about your engine and a service manual. Perhaps other forum members that have more knowledge will chime in with suggestions. Good luck.

Thanks for trying to help.

[Polycraft]

To me, my input, this sounds more like a problem with fuel. Either a fuel pump is getting weak, or maybe a blockage in one of the small passages/jets/mis-adjustment of low-speed idle mixture screw(s). If you have multiple carbs all idle mixture screws should be set identically, plugs can tell a story by viewing them.

Also, there's is a possibility that the gear counting coil, or a TPS (throttle positon sensor) could be changing thier resistance after they get warm from running. Once they cool back down they go back to what resistance they are supposed to be.

The only way to know that, is once well warmed up, and acting up, check thier respective resistance according to the proper service manual for your motor.

Good luck, post back on what you find out.

I think you are supposed to look at the electrical side of things first from a troubleshooting perspective. That said I heard a weak fuel pump can make vapour lock worse. And it seems to be easier to get going again after stalling since I insulated/ moved the fuel lines. Remember it has had time to cool down again when it stalls which is why I suspected vapour lock in the first place.

Do you know how I can diagnose a weak fuel pump?

[Solarman]

Easiest way to check fuel pump, removing main tube to carb(s) from pump (extend if needed), run into clean clear container (soda bottle/large cup/small bucket), or use a pressure guage (need service manual for proper reading). Put foot of motor into a tub to protect water pump (always water on water pump when starting/ turning motor over). Pull start, or electric start while watching fuel from pump going into container, it should be a fair steady stream when pulling, or electric starting. There should not be air pulling into sight glass on side of motor, and the pump should not spit n sputter, a steady fair stream while starting. Anything less, or a weak stream, you should disassemble pump carefully to inspect diaphragm and check-valves for damage.

I'm not sure what sensors you have on the 2004 model dt30, as Murray told you, they don't show parts pages for your motor. But to me, it sounds like you either have an intermittent sensor that changes as the motor warms up? Its difficult to pin-point your actual problem on this side of the computer?

Taking It to a dealership might be long and drawn out as well.

Good luck, post back on what you find out.

[Murray]

Found parts out of Japan.

https://en.impex-jp.com/catalogs/out...zuki/dt30.html

[Murray]

Narrow minded Canadian I am. Just because I couldn’t find parts in North America I assumed Suzuki no longer produced 2 strokes. I was wrong. Since they are still producing 2 strokes then one would assume they are producing service manuals. As Solarman mentioned some sensors to check your are going to need the factory specifications to compare against. The link below has nothing to do with service manuals but shows the countries that sell 2 strokes and presumably where one might find service manuals.

https://www.globalsuzuki.com/globallinks/

[Moonlighter]

Australia was a bit later than US/Eu in banning the import and sale of 2 strokes. July 2020 was the final day officially, although Suzuki stopped selling them here quite a few years ago as had most others, with only old stock being sold off in the last few years.

Of course it all relates to emissions.

Many remote areas of Australia where simplicity and familiarity were highly valued, plus dodgy fuel quality in those areas were the main reasons for the delays.

[Polycraft]

They like them in the Pacific Islands too, for the same reasons. injectors don't cope well with water contamination in particular.

[Polycraft]

Well I got out this morning. A lot of stopping and starting and absolutely no trouble with stalling so it looks like the Mechanic in a Bottle treatment did some good. Perhaps need one more trip to confirm.

[Murray]

Water in the fuel? I always add Seafoam to my tank as a preventative maintenance. If you do add a fuel treatment check the label that’s it’s safe for orings and fuel lines otherwise you’ll end up with a host of different problems. If possible avoid ethanol blended fuels.

[Polycraft]

Water in the fuel? I always add Seafoam to my tank as a preventative maintenance. If you do add a fuel treatment check the label that’s it’s safe for orings and fuel lines otherwise you’ll end up with a host of different problems. If possible avoid ethanol blended fuels.

The solution is designed to clean carburettors without dismantling them. It gets good reviews. There was probably some obstruction due to dirt in the carburettors. There was no sign of water when I drained the carby bowl. Also it ran fine most of the time over multiple tanks of fuel - just stalling in gear after a long run and being shut down for a while.