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  1. 07-29-2019, 08:11 PM #1
    mizzoukispot
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    98 Merc EFI won’t accelerate past 2800 rpms

    having an issue
    started as boat pausing and lurching above 2800 rpms. Got worse the same trip. Would be stuck at 2800 and lurch on its way up to 5000. (Just didn’t go over 5000)
    took it to lake and ran it up to 5500 after changing decent looking plugs and testing in line fuel filter for water... no water.
    Checked all spark plug connections as well as the plugs on the back of each cylinder or what’re it’s on the back of😳.
    Today it ran fine for a little bit, but now not go above 2800.
    Misc info
    i run dons old cocktail
    havent decarbed in a year but don’t do that often
    Pre mix gas 50-1 fir the last 12 years
    thoughts?
    Thanks for any help
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  2. mizzoukispot
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    #2 07-30-2019, 05:19 PM
    Ran fine today. I still dropped it off with my outboard mechanic that’s done a good job in the past. Thanks.
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  3. EuropeanAM
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    #3 07-31-2019, 11:15 AM
    Be sure to report back. Starting with the Basics would be in order (Compression Test, Spark Test, confirm clean/fresh QL77CC plugs ONLY, Fuel Quality, Delivery and PRESSURE tests.


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
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  4. rvaha
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    #4 08-01-2019, 02:06 PM
    Experts can confirm but a bad stator will cause this. I think this motor has one but not positive
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  5. mizzoukispot
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    #5 08-01-2019, 03:13 PM
    Thank you!
    sorry I didn’t put the sn. My silver plate with sn has worn off, but I’m sure that it’s stamped somewhere.
    This motor has been a really great motor. Absolutely love it. I hope that with your help, I can get it back into good working order! I want to keep my two stroke smoker as long as I can!
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  6. g352nv
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    #6 08-01-2019, 03:39 PM
    Quote Originally Posted by mizzoukispot View Post
    Thank you!
    sorry I didn’t put the sn. My silver plate with sn has worn off, but I’m sure that it’s stamped somewhere.
    This motor has been a really great motor. Absolutely love it. I hope that with your help, I can get it back into good working order! I want to keep my two stroke smoker as long as I can!
    The company that cleaned my injectors said the same. That's a great motor and to take care of it.
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  7. EuropeanAM
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    #7 08-01-2019, 04:51 PM
    Should have a stator with six (6) separate windings (one for each cylinder).


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
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  8. mizzoukispot
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    #8 08-02-2019, 11:23 AM
    Thanks again guys.
    The motor is a 98. I replaced the static back in 08. It’s 11 years old. Will check that.
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  9. mizzoukispot
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    #9 08-02-2019, 11:24 AM
    Stator
    that darn auto correct is my arch enema��
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  10. EuropeanAM
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    #10 08-02-2019, 01:05 PM


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
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  11. SilverFox579
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    #11 08-03-2019, 07:51 AM
    Quote Originally Posted by mizzoukispot View Post
    Stator
    that darn auto correct is my arch enema��
    I should say so.
    _______

    Phil
    '09 Hewescraft ProV
    '09 150 Optimax

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  12. cajunrgfm
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    #12 08-10-2019, 06:22 AM
    did you ever inspect or swap the steel reeds to carbon fiber ?
    Quote Originally Posted by mizzoukispot View Post
    having an issue
    started as boat pausing and lurching above 2800 rpms. Got worse the same trip. Would be stuck at 2800 and lurch on its way up to 5000. (Just didn’t go over 5000)
    took it to lake and ran it up to 5500 after changing decent looking plugs and testing in line fuel filter for water... no water.
    Checked all spark plug connections as well as the plugs on the back of each cylinder or what’re it’s on the back of.
    Today it ran fine for a little bit, but now not go above 2800.
    Misc info
    i run dons old cocktail
    havent decarbed in a year but don’t do that often
    Pre mix gas 50-1 fir the last 12 years
    thoughts?
    Thanks for any help
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  13. mizzoukispot
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    #13 08-13-2019, 07:19 PM
    I do think that the original reeds were switched out about 5 years ago. But I’m not sure. Could this be an issue? Thanks
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  14. g352nv
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    #14 08-13-2019, 08:20 PM
    Quote Originally Posted by mizzoukispot View Post
    I do think that the original reeds were switched out about 5 years ago. But I’m not sure. Could this be an issue? Thanks
    Just pull the cover off and look. It's super easy I didn't even have to take the lower fairings off. I can remove the reeds in maybe 15min
    Last edited by g352nv; 08-13-2019 at 09:02 PM.
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  15. g352nv
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    #15 08-13-2019, 09:07 PM
    BTW have you replaced the fuel hose? The bulb also? I have the same year motor and tore it down last week. I installed new reeds, plugs, coils, check valves, vacuum hoses and fuel hoses. The hoses were BAD. I did them all then pulled a part the VST and cleaned it. Then when I put it back together the two small fuel hoses on the top of the VST were done! They looked ok on the outside but when I pulled them off black gunk came out and pieces of the hoses came off as well.

    I would start with the fuel hoses FIRST then if all that is ok I would look at the reeds. Just my opinion. I also had the injectors cleaned and they were way off. Before the cleaning the plugs were wet. Now they look awesome. With a motor this old you'll need to check all basic stuff out.
    BTW I have the manual. If you need a link to it I can send it to you. Its come in real handy as well as info and parts from Don lol.
    Last edited by g352nv; 08-13-2019 at 09:12 PM.
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  16. mizzoukispot
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    #16 08-14-2019, 08:49 PM
    Great advice from all! Thank you. Will check all of that!
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  17. g352nv
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    #17 08-14-2019, 08:50 PM
    Quote Originally Posted by mizzoukispot View Post
    Great advice from all! Thank you. Will check all of that!
    Start by replacing that fuel line. Call Don he has a kit.
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  18. mizzoukispot
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    #18 08-15-2019, 07:09 AM
    The boat has been in the shop now since I received Dons advice on what to look for. Thank you for all the advice. Please feel free to keep letting me know thoughts.
    I haven’t heard back as to exactly what the problem is.
    Going through my records, it looks like fuel hoses were replaced 3 years ago.
    Sounds like ther could be a lot of culprits here that could be causing this issue. My guy is suppose to be running it today. I should know more soon.
    Again, thanks for all of your contributions.
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  19. mizzoukispot
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    #19 08-23-2019, 09:35 PM
    Replaced stator and cdm. Says it’s running great. Pick it up next week. I’ll post if it’s still acting up. Thanks for all of the help!
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