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Suzuki DT70 starts but wont run

watergatorwatergator Fort Pierce Posts: 153 Deckhand
I recently got a 70 hp Suzuki 4 stroke with an unknown history. This is my first fuel injected motor so I’m trying to get my bearings on it. The motor will start, but quickly dies when the starter is stopped. I was able to get it to start and run normally by giving it some throttle while cranking, and once it was started it ran and idled fine, but repeated the problem if it was turned off. It has been suggested that I the IAC valve is bad, but the motor idles once it is started so it doesnt really match the symptoms I have seen before with an IAC failure. My first suspicion is that the injectors need to be cleaned, but I wanted to get some guidance here before I really started diving into it


  • MelbourneMarkMelbourneMark Posts: 2,128 Captain
    See if you can buy/borrow a small portable gas tank to hook up to it.  Try to narrow down if its fuel flow related issues.  

    I had to do that recently to my boat and it helped me narrow down the issues.  mine turned out to be fuel tank related issues.. 
  • surfmansurfman WC FLPosts: 5,981 Admiral
    Does it have any kind of fuel filters? there may be one mounted on the engine, replace it if there is? Do you have a service manual, try to get one of those too.
    Tight Lines, Steve
    My posts are my opinion only.

    Be thankful we're not getting all the government we're paying for.  Will Rogers
  • FS DanFS Dan Posts: 2,353 Moderator
    I find it helpful to use the exploded engine diagrams from the online parts places to locate an find any unknown filters.
    you don't always need to replace them, a lot of the time, just knowing they are there, so you can clean them with some carb cleaner, is a help.

    Formerly Catmandew
  • larrywittlarrywitt Posts: 2,744 Moderator
    Sounds erratic, it could be electrical. Throttle position  sensor , key switch, lose wire to name a few.
  • watergatorwatergator Fort Pierce Posts: 153 Deckhand
    Somehow I missed these replies or else I would have been back sooner. The starting problem ended up being a simple fix that was solved by replacing the spark plugs. Judging by the state of the oil, I dont think the scheduled maintence was performed the way the previous owner described, so I am continuing to dive into the engine to hopefully turn it into a reliable machine. 
  • larrywittlarrywitt Posts: 2,744 Moderator
    That`s good news. There is a benefit to having problems  early on. Your learning curve has started on this motor. Now you will have many great days on the water to look forward too.
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