suzuki dh50 in limp mode until warm

[rocketman10]

When I first start up it won't go above 3000 rpms. If I try to go higher it starts pulsating. after a few minutes it suddenly starts running fine. Then it seems ok the rest of the day.

[Harper2]

No lights, no alarms? What's a dh50 (DF or DT)? Describe "pulsating" a little better (like cutting out pulsating or more like surging?). Carbed or injected? These are the kinds of things you need to post for anyone to be able to help.

[rocketman10]

It is a df50 2006 4 stroke. It starts right up and idles fine. I pull out of the boat ramp basin and push the throttle. It runs smooth up to 3000 rpms then starts pulsating like a rev limiter is kicking in. If I drop below 3000 it runs smooth. I tried tightening battery cables, shutting it down and restarting. nothing helped. After 4 or 5 minutes running below 3000 I tried again to throttle up...it ran right up to 6000 no problem. I went on fishing and shut it off several times for up to an hour and when I restarted it ran just fine right up to 6000. No missing or sputtering. It only seems to happen when I first start up at the ramp. No lights or alarms. I put in a new tach when I got the boat. The 4 second beep works and the lights come on for water, oil, etc. then go out when the beep stops. Tach works...when I turn key on tach goes to 1000 but once started it seems to work ok.

[Harper2]

Okay, that kind of info helps. The tach goes to 1000 before start as an hour indicator; it means that you have around 100 hours on the motor. I'll see what I can find, and others will probably have some pointers for you to check. Give us a little time. In the meantime think about what kind of maintnenace you've done, if any, on the fuel system. We'll probably start there.

[rocketman10]

Right after I bought the boat I had an instance where the motor died. I checked and the fuel connection to 6 gallon portable tank was loose allowing air to enter line. I replaced everything but the tank...new fittings, connectors, hose, bulb, inline filter. It never stalled again. I verified the vent is working on the tank. When It is pulsating I tried pumping the bulb but it was already hard so I don't think it's a fuel delivery issue.

[artdf175]

A few basic questions
Being a 2006 motor. How many hours?
Replace plugs regularly ? Check valve clearances?
Do you only run on the 6 gallon tank or does your boat have a built in one?
The 3000 rpm sounds like it goes into a limp mode
Have you cleaned the fuel filter in the motor area -should be just prior to the fuel pump
One other item the come to mind would be the engine temperature sensor
Check the electrical connection and would test sensor with an ohm meter per the service manual
Art

[rocketman10]

I went ahead and took it in for service. The tech found a code for gradient temp. He says it's either the sensor or one of the anodes has broken off and partially blocked the water flow. He says it means the temp is going up too fast and the motor goes into limp mode. After tstat opens and temp stabilizes the motor goes back to normal run. They are going to pull the anodes and check them if the sensor checks out. They are also going to check the pump and flush the engine with the foot off to make sure there is good flow.

[Paul Stanley]

Hello

Hi, my df50 is having the same problem. What was the end result for yours? Thanks