88 dt55 stalling at idle

[Riverratdt55]

Hi. New to forum and suzuki. I have a 1988 dt55 that will start and idle fine for 15sec then dies. Duration of idle time before sputtering out seams to decrease with engine temp. I have good compression, spark, new fuel, good fuel flow from tank to carbs. Cleaned out carbs, deleted thermostat (condition happened with and without tstat installed) deleted fuel quick connector, happens on both fuel tanks and lines etc. what do you guys think is the problem? TPS/timing issues? Any help would be appreciated. Thank you.

[mphelle8vld]

Every time you start the motor the CDI advances the timing an additional 10 degrees for 15 seconds, then it returns to whatever the idle adjustment switch is set to. I would check the timing at idle with a light, could be a bad idle switch or maladjusted TPS.

[Riverratdt55]

Is there any way of checking the TPS and idle switch? I checked some of those wires out with a volt meter and didn't find any power with key on only o.l. And ground. Could not get any resistance off of them either. I don't understand how they work I guess. The idle switch didn't change rpm when switched. I have not tried a timing light yet but will this weekend if it will quit raining. Thanks for the info.

[mphelle8vld]

The switches can only be checked with resistance, If the idle switch is bad the timing defaults to 6ATDC, resulting in a very low idle or stall. I'm in St Louis so I know what mean about the rain, let me know what you find on the timing.

[Riverratdt55]

Sounds like that is very possibly the issue. Do you know of a way to bypass that switch so base timing is say 6'BTDC? Also am I supposed to see any voltage to the TPS? I wonder if I have a faulty control module? I'm in pacific about 30min from STL and can't wait for the rain to stop. Thanks for all the info.

[mphelle8vld]

If you remove the switch and put a jumper wire in its place the timing will be TDC and give you a high idle of around 1000, fine for a jet but will be hard shifting on a prop lower. The tps is a double wiper arm on-off switch, one arm tells the CDI when the throttle is closed, the other advances the timing when the throttle opens about 15 degrees. I was unable to send you a PM, you may have it disabled in your preferences, feel free to send me one.

[Riverratdt55]

Installed the jumper and adjusted carbs and got to idle. Took my boat project out for the first time yesterday. aside from being happy how it handled the engine ran and idled good. Didn't die on me once. Thank you for all the help.

[mphelle8vld]

You got it ready just in time, the rivers should be settling down soon. I'll look for you on the Meramec, Mike