2000 DF70 Surging Problem

[E Miller]

I am looking for some assistance. I have a 2000 DF 70 4 stroke that surges when I increase the rpms to 2800-3000. I cannot get it to go past 3000 rpms. When I try, it sounds like it is loosing power but never stalls. I noticed the temp light comes on within 1.5-2 minutes of surging. I have had my mechanic look at it (however it wouldn't do it out of the water at his shop) and nothing showed up on the computer check. He said it could be a bad modulator but which one is anyones guess. It will do this wheather sitting at the dock in netural or trying to go across the water. It starts fine and idles nicely and runs smoothly until I reach 2800-3000 rpm then nothing but surging. I'm at a loss of what to do.

 

[clanton]

Re: 2000 DF70 Surging Problem

First guess is shift switch, diagnostic check should have checked the switch. Modualtor your word or mechanic`s? Don`t think this motor has one. The switch is located starboard side of engine clost to the shift linkage. When you shift into farward or reverse the swich closes and tell the engine computer the engine is in gear. In netrual the switch is open engine computer limits the engine RPMs to about 3000 rpms. 2nd guess could be temp related. Check engine temps with melt stick or laser temp checker. 3rd guess fuel system, test system with fuel pressure tester. If temp light is on , overheat alarm should be beeping.

 

[E Miller]

Re: 2000 DF70 Surging Problem

Captain,

Thanks for your reply. The word modulator was the mechanics word. I will check into the shift switch. Thanks again.