1989 DT115- High idle 'scream' then chugs/quit

[frustratedboater]

I am working on an 1989 DT115 and am experiencing very high idle right at start up. It runs this way for about 20 seconds then it struggles to run. The butterflies in each carb are closed. Is there any reason why it behaves like it is doing? The carbs are super clean and compression is 95 in each of the 4 cylinders.

 

[99yam40]

some outboards advance the timing at start up and then drop timing back to normal, this causes a fast idle during the warm up.
service manual for your motor should give specs for timing, and is easy to check to see what it is with a timing light

 

[frustratedboater]

some outboards advance the timing at start up and then drop timing back to normal, this causes a fast idle during the warm up.
service manual for your motor should give specs for timing, and is easy to check to see what it is with a timing light

I appreciate the tip. I didn't see where to make timing adjustments so thought I'd ask. I have Merc, Yam, Evin manuals, but not this motor, of course! I'm not sure if my Yamaha manual covers this as they swapped many years ago (I think..). Thanks

 

[99yam40]

I am not any help on that old Suzuki, just mentioned how some motors advance timing electronicky to increase idle RPM

 

[frustratedboater]

I am not any help on that old Suzuki, just mentioned how some motors advance timing electronicky to increase idle RPM

Yeah, I understand. I found a manual online and it said that the timing is non-adjustable like you said. It looks like a carb issue as the idle/air adjustment is not like usual outboards (1-1/2 to 2 turns). It calls for 1 to 1-1/4. That surprised me. They were too far out and had too much fuel going to it.
Also, I read that it revs high, then drops down like you said. You were a huge help!! I appreciate the reply..