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Idle issues


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Just picked up a 1995, 1830SS with a little over 100, yes one hundred, hours on it. The previous owner didn’t use it the last two years except for about 5 hours a year. anyways, It starts when I choke it, and keep the throttle about 50%. But, it still only runs at about 800RPM with it choked. I let it run today for about 10 minutes at that rate so it was warmed up. As soon as I ease off the choke it dies. Won’t start in neutral with no choke either. Just trying to get some ideas about what it might be? Mercruiser 4.3 LX

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Drying out gasoline in the fuel system causes a need for more choke.  It  can also be the idle is adjusted so    LEAN      that it stalls as the throttle is moved to any higher opening.

It can be so sensitive that it will not run as weather changes.  I did that to my 1996 Evenrude 30 hp. I forgot to use some Seafoam this year.  I turned the idle mixture OUT  a 1/4 more of a turn. Runs perfect again.  Some carbs are that critical.  Carefully check replace  the sparkplugs.  Have the auto place LOOK UP the correct PLUG NUMBERS. You may have the wrong ones in the engine now... Replace the distributor & rotor

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So I’m going to get the fuel drained (of course it’s about 3/4 full), spark plugs, fuel filter, distributor cap and rotor, then try it from there. If it still runs rough I’ll adjust the idle mixture screws. Hopefully with all that she’ll be good! What kind of fuel additive do you guys usually use? 

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Seafoam.......... DO NOT PUT IN E-10 in a old unused boat !!   E-10 ....WILL  WILL DISOLVE ALL the Varnish in ALL the fuel system at ONCE !!  BEEN there more than 1 time.  Stay with NON E-10 for the first tank & Seafoam. It disolves Varnish SLOWLY. The carb can pass slowly dissolving Varnish easily.

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Well There is a accelerator pump on many 2 throat carbs to help solve your problem. It may be worn out . Or misadjusted. That will cause your symptoms. Is there a metal tag on the carburator ? can you take some pictures of the throttle sid of the carb ?

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It’s a 4 barrel. I only had a little bit of time this weekend to mess with it but I haven’t adjusted any linkages or idle screws yet. I had just enough time to run it to operating temp to see if it would make it better. I’ll get some pictures as soon as I can and post them up! I’m thinking it’s bad gas and just needing a tune up cause it only has 105 hours, just needs more tlc and run time 

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Does the carb have mechanical linkage to open the secondary ? Or vacuum setup ?  Are the secondaries open the slightest bit ?  is yes? that is your problem / part of it.  They need to be PERFECTLY shut closed. No leaking of any air.

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