Thread: 04 125hp help

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  1. #1
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    04 125hp help

    04 125 elpto
    0t800609
    Looking at a boat that has this motor on it. Few ? Is this the 2+2 model I have read negative comments about, if so are the comments warranted . Motor started alright but it took about 4 shifts of the gear shift before it ever engaged at the prop. No grinding. Then about 4th time trying it engaged and never had problem again. The guy that has it only has took it out couple times. He said it done the same thing with him. Is this likely a linkage issue at motor or some sort of shifter issue at throttle control. Going to lake trial it Saturday so all advise appreciated. Any idea of how much to repair for price negotiating?
    thanks

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    #2
    hard to say from here , could be control box could be gearcase
    .................................................. ...the scariest thing in life is the unknown ...................................

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    #3
    Make sure it's warmed up before shifting.

    I have an 03 125 2x2. Solid motor for me. There is a process to starting when cold but once you have that down she'll always start right up. Need to let it warm up before shifting. Starts best when level. Needs to be run after long periods of idle. At a certain RPM the second set of carbs will start to kick in...runs a little rough at this spot...but again this is part of the learning curve. I've heard that some owners will add low speed jets to the carbs that don't have them.

    Starting procedure:
    Pump bulb very firm
    Make sure motor is level
    turn key and push in to prime for about 10 seconds.
    (I have to give mine just a tiny bit of advance throttle first start of the day)
    Turn key to start
    Once it fires I need to push the key in a couple of times before a solid idle speed settles in.
    Let it warm up.

    Check the solenoid (ENRICHENER VALVE) to make sure it's working when the key is pushed in.
    Last edited by WisconsinF; 08-17-2022 at 08:12 AM.

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    #4
    not heard that one yet
    .................................................. ...the scariest thing in life is the unknown ...................................

  5. Member 06 SB's Avatar
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    #5
    The 2+2 are solid motors if tuned properly. They are an ancient design. On a bass boat they are fine but a pontoon or ski boat they are a pain due the 2 cylinder cutout at 1800 RPM. Those fuel lines are going to need replaced FIRST due to ethanol deterioration along with the shifting issue. Oh yea, clean those carbs!

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    #6
    ^^^^^ +1 early ones had some crank problems later ones are very reliable
    .................................................. ...the scariest thing in life is the unknown ...................................

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    #7
    [QUOTE=biskitboy;12633128]04 125 elpto
    0t800609
    Looking at a boat that has this motor on it. Few ? Is this the 2+2 model I have read negative comments about, if so are the comments warranted .

    Yes it's a 2x2 and no they aren't warranted (I've had 2).....bulletproof engine, but, quirky shift at 1800rpm's (No biggie to me, but, some complain about it) when bottom 2 cylinders kick in. It also tends to idle a bit rough, but, both of mine were fine. Certainly no 4 stroke idle, but, no worse than the average 2 stroke. It's a powerful engine and will last a loooooooong time if it's not been abused and you maintain it properly. Both of mine were/are very reliable.




    Motor started alright but it took about 4 shifts of the gear shift before it ever engaged at the prop. No grinding. Then about 4th time trying it engaged and never had problem again. The guy that has it only has took it out couple times. He said it done the same thing with him. Is this likely a linkage issue at motor or some sort of shifter issue at throttle control. Going to lake trial it Saturday so all advise appreciated. Any idea of how much to repair for price negotiating?
    thanks

    You need to have a highly competent Merc 2 stroke mechanic go over it with the fine tooth. Both of mine required it to get them dialed in. Fortunately I am very friendly with one of the best.

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    #8
    Quote Originally Posted by WisconsinF View Post
    Make sure it's warmed up before shifting.

    I have an 03 125 2x2. Solid motor for me. There is a process to starting when cold but once you have that down she'll always start right up. Need to let it warm up before shifting. Starts best when level. Needs to be run after long periods of idle. At a certain RPM the second set of carbs will start to kick in...runs a little rough at this spot...but again this is part of the learning curve. I've heard that some owners will add low speed jets to the carbs that don't have them.

    Starting procedure:
    Pump bulb very firm
    Make sure motor is level
    turn key and push in to prime for about 10 seconds.
    (I have to give mine just a tiny bit of advance throttle first start of the day)
    Turn key to start
    Once it fires I need to push the key in a couple of times before a solid idle speed settles in.
    Let it warm up.

    Check the solenoid (ENRICHENER VALVE) to make sure it's working when the key is pushed in.
    .....DEAD ON regarding the start up.....i raise the jackplate up slightly as well to reduce back pressure. Fires right up and like lightening the rest of the day.......

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    #9
    The 125 Merc that came on my 2000 TV-18 has been as solid as the boat since new.
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    #10
    I bought the boat that had this motor. Shift cable adjustment I think is going to fix the shift problem. Would y’all replace all fuel lines or just the one from tank to fuel pump and not all the small ones at carbs? Does this motor need a water separator ? I normally run non ethanol. Should I disconnect the oiler and go premix or leave it hooked up. Prop looks to be soot free right now, have no idea of history of motor but looks really clean, see no evidence of any major maintenance.

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    #11
    Quote Originally Posted by biskitboy View Post
    I bought the boat that had this motor. Shift cable adjustment I think is going to fix the shift problem. Would y’all replace all fuel lines or just the one from tank to fuel pump and not all the small ones at carbs? Does this motor need a water separator ? I normally run non ethanol. Should I disconnect the oiler and go premix or leave it hooked up. Prop looks to be soot free right now, have no idea of history of motor but looks really clean, see no evidence of any major maintenance.
    I'd definitely install a separator.....after that it's impossible to tell you much else.. If you have the old gray mercury fuel lines you can't get those disintegrating POS replaced fast enough. Check the fuel pump accelerator as the diaphragm disintegrates over time. My 115 caught fire and burned up due to the VOLTAGE REGULATOR shorting out....so I'd check it out closely. (To bad as it was a great engine)

    You really need to take it to an expert to carefully look it over. That's what I did with both of mine. With my 2x2 115 I had an expert professionally rebuild the carbs. I did replace all the original fuel and oil lines, fuel accelerator pump, plugs, etc myself.

    I took my 125 2x2 to the experts and had them rebuild the carbs and numerous other items. My goal was to bring the engine back to as close to new as possible. I'm just very fortunate to be friends with an expert....in fact, I bought my 125 from his marine dealership.

    One other thing, both of my engines oil injection systems worked flawlessly.
    Last edited by Slicefixer; 08-24-2022 at 09:46 PM. Reason: Brain fart mistake

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    #12
    Seperators are not recommended on these engines , maintenance on fuel system parts is very good idea
    .................................................. ...the scariest thing in life is the unknown ...................................

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    #13
    Quote Originally Posted by JOE54 View Post
    Seperators are not recommended on these engines , maintenance on fuel system parts is very good idea
    But why Mr. Joe? I know you've got a tremendous amount of knowledge and experience regarding outboards so I'm genuinely curious as to your opinion.

    If the fuel system is sealed from start to finish I simply don't understand why a properly installed fuel/water separator would present any issues. What are the potential downsides vs the ability to ensure zero water enters the fuel to the engine.

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    #14
    for many years MERCURY MARINE has not approved of the addition of any restrictions that can cause a lean running condition added to fuel line on an outboard
    .................................................. ...the scariest thing in life is the unknown ...................................

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    #15
    Quote Originally Posted by JOE54 View Post
    for many years MERCURY MARINE has not approved of the addition of any restrictions that can cause a lean running condition added to fuel line on an outboard
    I get that, but, why would a properly installed separator that's in a sealed environment cause a lean condition? There is no void for air to entire the system, the fuel is the exact same fuel that's in the tank. In theory it's still being pulled from the tank with the separator itself acting as nothing more than a small gas tank due to it being inline with the fuel line to the engine itself....where's the restriction?

    It simply makes zero sense to me, but, I'm a 20 handicap with outboards.....i do have more experience than the average guy, who knows next to nothing, but I'm definitely not an expert.

    The reason I ask is this, I just spent a week rebuilding the entire fuel system on one of my diesel greens mowers (pain in the arse) due to h20 in the tank wreaking havoc. Diesel that had been sitting in the tank for a few months dissolved into biological "snot" and fouled the entire system. This had never happened before in over 2 decades of dealing with equipment.

    I realize refined unleaded is different than diesel, but, I've experienced WAY more problems with unleaded, corn or no corn, than I have in regards to my diesel engines.

    This much I learned, I want to avoid this ever happening again to ANYthing I own.
    Last edited by Slicefixer; 08-23-2022 at 09:00 AM. Reason: Misspelling due to "spell correct"

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    #16
    air not the problem flow is problem , now remember i did not say i wouldn't do it said not recommended
    .................................................. ...the scariest thing in life is the unknown ...................................

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    #17
    Quote Originally Posted by JOE54 View Post
    air not the problem flow is problem , now remember i did not say i wouldn't do it said not recommended
    Hehehe Hehehe hehehe......luv it Brother Joe.....hehehe

    I KNOW you've had to fix what idiots like myself create thousands of times, including many a fuel system. That's why I was asking you to explain things. Having now had to rebuild an entire fuel system for my FIRST time, i want it to be my LAST time....😉

    Btw, frigging mercury says no lithium starting batteries.....until they purchase a lithium battery manufacture (my understanding anyway)....that's why I'm a bit skeptical nowadays.

  18. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #18
    Quote Originally Posted by Slicefixer View Post
    Hehehe Hehehe hehehe......luv it Brother Joe.....hehehe

    I KNOW you've had to fix what idiots like myself create thousands of times, including many a fuel system. That's why I was asking you to explain things. Having now had to rebuild an entire fuel system for my FIRST time, i want it to be my LAST time....

    Btw, frigging mercury says no lithium starting batteries.....until they purchase a lithium battery manufacture (my understanding anyway)....that's why I'm a bit skeptical nowadays.

    That last statement is based on some "fake news"... Mercury hasn't authorized the use of Lithium batteries for any of their outboards or sterndrives. Not saying it will "never" happen, just that it has NOT happened.

    Brunswick bought Relion... but they didn't spend all that money to build cranking batteries. MUCH more about Strategic market placement for their new Electric Outboard series, and the purpose-built batteries planned for it.


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    #19
    As I stated, "my understanding".....i stand corrected. 😉👍

    However, can you please elaborate on their recommendation regarding not adding a fuel separator into the fuel system, particularly a carburated 2x2?

  20. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
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    #20
    As a general rule, Mercury does not recommend adding additional filters to the system with most of their engines, as this can add a fuel supply restriction, resulting in a lean-running engine.

    If you choose to add one, it should be changed AT LEAST once per season, AND all measures possible should be used to reduce the restrictive nature of the fittings (straight fittings, no more than 9' flexible line, 3/8" from tank to filter, filter to bulb, then 5/16" from there to pulse pump, eliminate un-necessary splices and connectors, and then verify the fuel supply line pressure (vacuum) at all engine RPM's does not exceed 1.5" hg.


    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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