Quicksilver QS-7.5 generator won’t start

Discussion in 'General Maintenance/Repair Questions' started by 94SD370, Jul 19, 2022.

  1. 94SD370

    94SD370 New Member

    10
    Jun 30, 2022
    Lake Winnipesuakee, New Hampshire
    1994 Sundancer 370

    Quicksilver QS-7.5G Generator
    Model #9679-0
    Serial#1255117
    Mercruiser 7.4L “Blue Water Inboard” Thunderbolt IV Ignition
    Serial #F215722
    This is a QS-7.5 model plate says 9679-0. I purchased this boat last season and the generator has never operated normally. I did get it to run once or twice, a few times it ran for a few minutes then quit. Most recently it just turns over a dies after releasing the start button.

    It is not hooked to a carbon monoxide detector

    I removed wire 85, isolating all safety switches

    It appears to have a recent tune up. Fresh oil, new fuel pump, new filter.

    During the starting sequence there is no movement of the throttle or connected governor assembly. I suspect I should see movement here?

    It is getting fuel to the carb. I’m only a DIY guy (learning) but I read something about the fuel solenoid and the start sequence changing when the button is released.

    Any ideas?

    Thank you in advance.
     
  2. Wanderer 290

    Wanderer 290 Well-Known Member

    730
    Jul 1, 2019
    Traverse City
    01 sea ray 290 sundancer
    Twin 5.7 b3’s
    What year, how many hours, salt or fresh water, gas or diesel?
    Absolute 1st thing to do is change the plugs. If one can get a season or 50hrs on a set that is pushing it.
     
  3. markrsimon

    markrsimon Active Member

    374
    Sep 1, 2018
    Cleveland, OH
    92 Searay 400 Express
    7.4L Mercruiser Gen V
    The only carb movement during starting is the choke. The choke is composed of a choke solenoid and a bi-metal strip. It will pulse (on/off) for a few second in each spot while you crank.

    If it starts then dies - do you have a set of switches on your main power panel inside the cabin? If so, the cabin switch must be in the middle run position, in order to use the switch on the generator itself.

    There is a fuel solenoid as well, bottom corner of the carb, and your fuel pump, plus the inline fuel filter on the carb, and you probably have a marine fuel filter mounted on the boat before the generator. I would try a bit of starting fluid first (should be a gas unit right?) before opening up the fuel system. If you open up the bowls on the carb, expect to buy new gaskets (not cheap) and get some permatex aviation gasket sealer and use very sparingly - you’ll need it for the fuel inlet plate on the left side. It wont leak this season, but it will next season - so use a tad of aviation permatex now.

    Finally, there is the hotwire procedure I posted awhile back, and a ton of other good info here, plus manuals:
    http://www.clubsearay.com/index.php...tarts-but-dies-in-3-5-sec.11950/#post-1162575

    Keep us updated and let us know if you get hung up somewhere along the way.

    -Mark
     
    94SD370 likes this.
  4. 94SD370

    94SD370 New Member

    10
    Jun 30, 2022
    Lake Winnipesuakee, New Hampshire
    1994 Sundancer 370

    Quicksilver QS-7.5G Generator
    Model #9679-0
    Serial#1255117
    Mercruiser 7.4L “Blue Water Inboard” Thunderbolt IV Ignition
    Serial #F215722
    1994ish, freshwater, gas, and 238hrs. I have changed the plugs, they were black, possibly from multiple start attempts and not running or something else? From what I can tell, the air filter is clean.
     
  5. 94SD370

    94SD370 New Member

    10
    Jun 30, 2022
    Lake Winnipesuakee, New Hampshire
    1994 Sundancer 370

    Quicksilver QS-7.5G Generator
    Model #9679-0
    Serial#1255117
    Mercruiser 7.4L “Blue Water Inboard” Thunderbolt IV Ignition
    Serial #F215722
    I was not aware that the panel switch mattered, so I placed that to run and retested everything I mentioned prior.

    I removed the air cleaner and sprayed a bit of carb cleaner into the carb. It fired right up and died when the cleaner burned off. I found that it will continue running if I continue spraying. So now I’m thinking fuel issue. The fuel pump, and in line filter look new. There is a fram c-1110PL filter mounted on the firewall. I also noted the choke movement during start, and it did pulsate like you described, however that solenoid looks worn, and possibly damaged. I’m not sure what it should look like. The carburetor solenoid also looks original, (is painted the same as the block.)
    A451960A-2D1B-467B-8592-4DBC9A1815D5.jpeg A451960A-2D1B-467B-8592-4DBC9A1815D5.jpeg
     
  6. markrsimon

    markrsimon Active Member

    374
    Sep 1, 2018
    Cleveland, OH
    92 Searay 400 Express
    7.4L Mercruiser Gen V
    Disconnect the fuel line from the carb, and place it into a container safe for gas (HDPE bottles work great for this). Then try cranking and make sure fuel is flowing. If that checks out - next step would be to tear down the carb and clean it. I would not say a rebuild - just take the big pieces off - clean everything you can, including the float pin and main jet - and put it back together. There is really only one place that sells the gaskets - partsfortechs.com.
     
  7. 94SD370

    94SD370 New Member

    10
    Jun 30, 2022
    Lake Winnipesuakee, New Hampshire
    1994 Sundancer 370

    Quicksilver QS-7.5G Generator
    Model #9679-0
    Serial#1255117
    Mercruiser 7.4L “Blue Water Inboard” Thunderbolt IV Ignition
    Serial #F215722
    Thank you Mark, I will do that this weekend.

    I discovered something else of interest. I reached out to parts for techs to see what a fuel pump would cost and discovered that the fuel pump for this generator is “not available”. They recommend a retrofit for a different pump. Interestingly, my generator already has the retrofitted pump. That makes me wonder if this pump is 1) compatible at all, 2) wired and plumbed correctly. I guess when pull the fuel line I will learn some more. Thanks again!
     

    Attached Files:

  8. 94SD370

    94SD370 New Member

    10
    Jun 30, 2022
    Lake Winnipesuakee, New Hampshire
    1994 Sundancer 370

    Quicksilver QS-7.5G Generator
    Model #9679-0
    Serial#1255117
    Mercruiser 7.4L “Blue Water Inboard” Thunderbolt IV Ignition
    Serial #F215722
    Fuel is flowing. I do have an initial spray from the jet, that stops when I release the start button. I found the choke solenoid to be broken, so I replaced it. Didn’t change anything. I moved on to replacing the fuel solenoid on the carb and unfortunately I broken the carburetor housing. I ended up ordering a new carb, hopefully I’ll get that done this weekend.
    1EA69095-382C-4429-898E-EC4C2386B690.png
     
  9. markrsimon

    markrsimon Active Member

    374
    Sep 1, 2018
    Cleveland, OH
    92 Searay 400 Express
    7.4L Mercruiser Gen V
    I wonder if your control board is fried. There are two T220 transistors at the top of the board - and one of them is for the ignition circuit. Those transistors are bolted to heatsinks - but the screws can come loose and it separates from the heatsink and cooks itself. It seems pressing and holding the start button gets things going, and when you release its up to that transistor to continuing providing 12v to the ignition circuit. This is what happened to mine - loose heatsink. I ended up hot wiring the engine (basically bypassing the control board) ensuring the engine would run before I spent the money on a new board. See the post I referenced above re hot wire.
     
  10. 94SD370

    94SD370 New Member

    10
    Jun 30, 2022
    Lake Winnipesuakee, New Hampshire
    1994 Sundancer 370

    Quicksilver QS-7.5G Generator
    Model #9679-0
    Serial#1255117
    Mercruiser 7.4L “Blue Water Inboard” Thunderbolt IV Ignition
    Serial #F215722
    New carburetor installed. It fired fired up, and ran well for about an hour then died. I discovered this time it is because of no water flow. (I did have flow at startup) I suspect the high temp sensor saved my generator. I can’t believe there is no alarm or codes on this thing! I will order a new impeller and see where that takes me. Thank again for all the help this far!
     

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