did a carb kit and still a poor low speed performance

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martinphantom

Seaman Apprentice
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Jul 12, 2005
Messages
47
86 johnson 25 hp tiller-adjusted cam roller-checked compression, 125 and 125-installed carb kit(pulled welch plugs)-low speed adj is't right though, starts at 1 1/2 turns out, but increases rpms when turned in, dies when turned out-all new fuel lines-checked screen on fuel pump-new plugs gapped at 40k-poor low speed performance(almost seems to be running on one cylinder)-runs great at WOT and idles ok,light shake. Sprayed cleaner degreaser on engine and loosened up a sticky throttle(haven't had it out since). Did a decarb-cleaned up a lot. Any suggestions as to what to try next?
 
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Goodoleboy

Chief Petty Officer
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Nov 20, 2003
Messages
555
Re: did a carb kit and still a poor low speed performance

I would suspect you still have a dirty low speed curcit.<br /><br />Sometimes you have to clean a carb a couple or three times, its not unusual on a realy bad carb.<br /><br /> Use the handy dandy Joe reevers trick. use a small wire with a very small L bent onto the end.<br /><br />Careful tho...dont wana brake that little sucker off in their.<br /><br />Hate to say it..but...cleaner uh gin !<br /><br />Good luck!
 
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G DANE

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Nov 24, 2001
Messages
2,476
Re: did a carb kit and still a poor low speed performance

I rarely remove the welch plug. Put a small amount of liquid gasket on the tip of your finger and wipe it round on top of the new plug. That way you will know it isnt drawing air there.
 
OBJ

OBJ

Supreme Mariner
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Dec 27, 2002
Messages
10,161
Re: did a carb kit and still a poor low speed performance

Martin....it would seem to me, from your post, the carb low speed needle is doing what it's supposed to do. All you need to do is adjust it right for better low end operation. Check the link below. It's a guide to setting the needle on single carbed engines by Joe Reeves.<br /><br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=28;t=029758#000001 <br /><br />Let us know how you make out.
 
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martinphantom

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Jul 12, 2005
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47
Re: did a carb kit and still a poor low speed performance

OBJ-I'd read the adj process in the manual before-but "thought" turning it OUT would increase rpms "obviously read it wrong" and "assumed" out would OPEN valve and IN would close valve. THANKS for pointing out my "stupid" error that I've overlooked for 2 weeks! Am off to try this again!
 
OBJ

OBJ

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Dec 27, 2002
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10,161
Re: did a carb kit and still a poor low speed performance

Nothing is stupid here Martin....fact is, when you turn the needle in, you are closing the "valve". But what you are doing is leaning the fuel mixture at idle. This is why it speeds up when you turn the needle in. Out, and you overload the engine with fuel....so to speak...and floods.
 
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martinphantom

Seaman Apprentice
Joined
Jul 12, 2005
Messages
47
Re: did a carb kit and still a poor low speed performance

Took the manual and tried to adjust per instructions. Does not respond as manual suggests. Idles fine. Runs like crap until the cam follower starts pulling away(I assume this is when the high speed jet kicks in-then runs great. <br /> I'm going out now to check the pack and coils with ohmeter-per manual-seems to run on one cylinder in low speeds.
 
fireman57

fireman57

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Aug 24, 2004
Messages
3,811
Re: did a carb kit and still a poor low speed performance

Sounds like you still have carb problems as when the cam roller starts pulling away this opens your butterfly in the carb to get it more air and fuel for your upper rpms. You may want to check your fuel lines for a small air leak. It has been suggested here that you take some grease and smear it on all the connections and wipe it off starting at one end until the problem shows up. That way you can pin it down to that connection. Fuel pump could be getting weak also.
 
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