Suzuki DT150 Running Problems

[oscartheclimber]

I have a Suzuki 150 EFI with just 59 hour on it (2003 model). THe problem is that it idles roughly, and under power - at all RPMs - the engine (at constant throttle) will change RPMs by about 500. The problem with the rough idle is always there, but the engine "hunting" at higher speeds seems to be intermittent. It also seems that I've lost some power (spped vs. RPM). I've added new fuel, run it at higher speed, tried different grades of gas, and just can't seem to shake the problem. Time to look under the "hood". Could it be a fuel injection problem, electronic - any ideas?

 

[oscartheclimber]

Re: Suzuki DT150 Running Problems

I pulled the plugs. All were wet - some more than others. I pulled the plug leads off at idle, at 1500RPM, and at 2200RPM. Besides the lower right I can't say that ther was any change in RPM - certainly nothing like I've ever seen on a car engine. But then again the engine is running so roughly it is difficult to tell. It did seem to be dropping a few drops of fuel while I had it running. Not sure if that was from flooding, or just fuel from a cylinder not firing.<br /><br />I didn't run it at higher RPM as it would start to rev up to 4000+ at constant throttle.<br /><br />I have a 77 Gal tank which is about 1/4 full right now. I guess that I will fill it and see if the full tank will boost fuel pressure.<br /><br />Any help is appreciated. I have to exhaust all options as getting it to a dealer is more than a pain.<br /><br />Boat is a Wellcraft Sportsman 210.

 

[ALouv]

Re: Suzuki DT150 Running Problems

We have a Suzuki 225 with the SAME problems. They started 3 months after purchase (2003). It has more hours at the dealer than in the water. This time was the worst.... it killed in the water after the gauges went crazy and the motor sounded like it would rattle off the boat. We just got it out of the shop and they changed all the plugs. We ran it for about 20 minutes and checked the plugs ~ black! We've tried getting the customer service people involved but they want us to deal with the dealer (who hasn't fixed the problem in 2 years!) They told us that a Suz. 225 is a rough idling motor (it has a MISS) and we are curious to know if this is true????!! We have the latest incident on video. What should we do???? What did oscartheclimber do???

 

[shep70057]

Re: Suzuki DT150 Running Problems

I have a 150, 2002 model and it is a little rough at idle and it's my understanding that it's because the motor drops 3 cylinders while at low R's. Other than that, my motor has been pretty reliable. The plugs are a little darker than I would like and changing to a different (hotter) plug is something I want to try. Mind you, I use synthetic oil with 87 octane gasoline.