1989 DT200 idle speed too high?

I have a boat with twin 1989 DT200's that has sat for the last 5 years. I now have both motors running fine after going through them and doing water pumps. The problem is that I think the idle speed is too high. I am running them on the muffs and when warmed up they both idle between 1250 and 1300 rpm in nuetral. <br /><br />I have adjusted both idle speed switches and they do change the idle from agout 1250 up to 1400 rpm. I also checked the adjustments on the carburators and they are closing fully. <br /><br />I'm wondering if this is just due to them being run on the muffs with cold water or if there is some other way to lower the idle speed? <br /><br />Any help would be appreciated.<br /><br />Thanks,<br />Rob

Re: 1989 DT200 idle speed too high?

The high idle speed is NORMAL on the muffs. There is no exhaust backpressure. Suzukis are very sensative to that.<br /><br />You will have to re-adjust the idle(s) when you dunk it. Or, put them in a test tank.

Re: 1989 DT200 idle speed too high?

Ok, thanks. That's good news since now it seems like both these motors are in better shape than I had expected and hopefully I can have the boat in the water in the next few weeks...<br /><br />-Rob

Re: 1989 DT200 idle speed too high?

It should still be dropping down after about 10 seconds or so.<br /><br />If you remove the oil tank you will see an electrical device on the bottom carburator. Its called the throtle position sensor. Unplug it and using an ohm meter see what it reads, it should read 200~250 ohms with the throtle plates all the way closed (disconnect the throtle linkage to make sure). There are three screws that hold the sensor in place, you loosen them and turn it to make the adjustment. Also, there is a small black plastic cover (held in place with two little screws) that hides the gear on the throtle shaft from the lower carb and the corresponding gear on the sensor. You might have noticed a small steel pin held in place int he plastic cover. It is used to push though a hole in the shaft gear to align it if you remove the sensor. There are two little dots on one of the gears and a single dot on the other, they have to mesh with the single dot placed between the two dots.<br /><br />Anyway this is the thing that will set your overall idle, then you use the switch at the back to adjust it further. <br /><br />On Edit: Whoops, I should have told you, connect the ohm meter with the negative lead to the black wire and the positive lead to the green/red wire. It can be a bit of a pain to get it set right but its not physically difficult. Once its set right the resistance will come up dramatically as you open up the throtle.<br /><br />Thom