rebuilt 140 doesn’t like to idle

SSTKO81

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Rebuilt ‘81 140 doesnt like to start without really feathering the idle. -even if I’ve just shut it off, it won’t restart without pumping the throttle than holding it down to bring it up to 14-1600 RPM. After About 20-30 seconds of that I can bring it down to 1000 rpm and it’ll hang out there for maybe a minute or two than it begins to drop rpms and sputter as though it’s getting either too much or not enough fuel. If I grab the throttle and pump it a little it cames back up the 1500 rpm and the whole process starts over again. I was initially having some miss issues but that seems to have gone away once I bypassed the resistance wire to put a full 12v to the ignitor coil. Anyone have any thoughts? I’ve got good oil pressure at 40, fuel is fresh as of today, plugs were cleaned and gapped before firing, fuel pump is 3 years old but has less than 3hours on it. Fuel lines are new and carb was rebuilt last spring.
 

achris

More fish than mountain goat
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Did you give the carb a clean in the 'rebuild' process? And check for throttle shaft wear? Have you checked the distributor shaft for wear? Have you pointed a timing light at the timing marks to see if the timing is drifting?

Chris...........
 

Maclin

Admiral
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May 27, 2007
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Kinda sounds like the initial timing may be retarded, and only runs when the weights move out a bit at the 1400-1600 rpm's. Once it spins back down the weights come all the way in and not enough timing.
 

achris

More fish than mountain goat
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or an air leak around a worn throttle shaft...
 

SSTKO81

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I don't see any excessive play around the throttle shaft and linkage feels pretty nice and smooth; I'm gettin response from the idle air screws when I adjust them... tho I suppose there could always be some crud down in there... I don't disagree w/ timing. I didn't have my timing gun yesterday to check it out but I suspect it could be out by a few degrees. I'm not sure that explains why I'm having to pump up the throttle to get fire.
I'll get my timing gun this evening and see where it sits. What is a good initial setting (ground zero) for the carb just to make sure we're on the same page?
 

SSTKO81

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Started tinkering with the carb this morning and the timing and found its wanting to sit about 12* btc. Could hear a miss so started checking my spark with the timing light and found my #2&3 are just kinda doing what they want.... 1&4 are fine.... I don’t have time to play The is it this or that game so I’m thinking of just throwing a dizzy at it
 

SSTKO81

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Oh, also it has suddenly just decided to keep running even after I turn the key off... so that’s new
 

Bt Doctur

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Dieseling is not good. timing, lean running, temp too high, too high a rpm setting
 

SSTKO81

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Yeah.got some weird stuff going on. Replaced the cap, rotor, and wires and I’m hitting on all cylinders -sounds better.... still only happy running @ 12* btdc and I’ve got idle screws on the carb turned almost all the way in (maybe 1/2 turn out) and fast idle screw has to be turned way in to keep it idling at 1000. About 900 is the lowest I’ve been able to get it, and it sounds terrible. And when I does die I get a slight back fire through carb and gasoline splashes out. I’m confident it’s a carb issue, but not sure what to look for. Looking down the throat of the carb while it’s running it looks wet around the venturies. -good stream when pushing throttle and good response from the engine. It’s just start up and idle that are really suffering
 

Bt Doctur

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and I’ve got idle screws on the carb turned almost all the way in (maybe 1/2 turn out)

Try opening them to 3 1/2 for starters , then adjust idle speed
 

SSTKO81

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Took the carb apart this morning and found some crud in the little passages for the venturies, float was also a little out of adjustment. I’ll drag it down to the water in a while and see what happens.
 
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SSTKO81

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Still no go. Carb didn’t seem to make a difference. Still having to pump the snot out of it to get it started and timing won’t set down
 

SSTKO81

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I ran the mix screws out two turns then back in about another full turn. Idle is just all over the place, I have to baby it at the helm. And as soon as I put it in gear. Poof! Dead.
 

SSTKO81

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Cam and crank gears in proper alignment when cam installed.

Cam was never removed in the build process. Crank was replaced tho. Everything was marked and lined back up how it came out. I don’t believe it’s out. But if it were a tooth out one way or another is this the kinda performance I’d expect
 
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