DF70 periodic missing or stumble at idle

[manitoba1]

I was out on holidays and found my DF70 on occasion would almost seem to miss or stumble while a idle. Engine otherwise started and ran great and no problem at any speeds other than at idle or trolling speeds. The stumble was periodic and did not occur each time I was out. Any ideas out there? I may have had a bit of moisture in the fuel previously but have not changed any fuel filters in the few years I've had it. I heard something about a low and high pressure filter but don't have a repair manual. Any help or suggestions would be appreciated.<br /><br />Manitoba1

 

[jim dozier]

Re: DF70 periodic missing or stumble at idle

From what I've read here the fuel injection systems must scruptiously avoid water in the fuel. Get a GOOD water separating filter and change/clean it often. If its been a couple of years you are way overdue even for a carbed engine. It probably has less to do with engine hours than it has to do with time. Condensation in fuel tanks occur over time sitting not time running.

 

[clanton]

Re: DF70 periodic missing or stumble at idle

Drain the vapor seperator and catch the fuel in glass/plastic container. If you have anything except fuel, drain and flush all hoses, and injector rail. Fill the vapor seperator with Johnson engine tuner, let set 1 hour, start and run engine, after engine running clean change all filters, replace sparkplugs. Adjust idle iaw factory manual, Check fuel pressure and operation of idle control valve. If fuel pressure is low and there was water in the vapor seperator, replace fuel pump and fuel pressure regulator.

 

[Meggacatz]

Re: DF70 periodic missing or stumble at idle

YUP - sounding like water in the fuel. Even a little can cause the stumbling. I've been struggling with my water problem for a month now and it seems like I got it fixed now. Look at my post 'Suzuki DF70' and maybe you can get some ideas. Keep updating your thread and people will help with ideas. So far everyone is giving good advise and has been helpful. The water can be a frusterating problem.