1979 Evinrude 140943R - wont idle

scott hamilton

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(I thought I sent this to Joe Reeves but don't see it in my sent folder.)

Have had the motor for about 4 years and runs very well except at idle. Dies when moving from N to gear. I can quickly move throttle up past idle and all is well. I have done lots of reading here and after throwing my hands up took it to a shop who said it has lean sneeze. They claimed to do timing, link synch and carb rebuild. This improved the problem but now after about 20 hours of runtime it is back to where it was. I believe I STILL have a lean condition in the idle circuit. I have NEVER had such a cold blooded motor and yet runs great at higher RPM. I am going now to the launch to try and restrict the air flow into carb throat as described by Joe Reeves.

I read Joe Reeves idea about installing smaller jets. Where do I get these? And how do I know what the next smaller size is? Any other advice would be appreciated too. Thanks.
 

WrenchHead

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I can't help you on the jets, but you say after the shop fix it ran great. Sounds to me like you keep getting trash in your carb. Sometimes you can suck the trash out by running at high RPM, then going to full choke, then remove choke as engine drops to lower RPM, then when it goes back to high RPM, apply full choke again. Doing these steps a few times might suck the trash out of the carb. A cheap and easy fix. If that cures the problem then you need to find the source of the trash.
 

Bosunsmate

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Run it on muffs, if you get a sneeze then track it down doing fnger in carb joes method.
perhaps install a filter as Wrenchhead has a good point there
 

racerone

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Compression test is step # 1 on all outboards when stalling happens.
 

Faztbullet

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You have to run it in a barrel or lake as it must have backpressure, it will lean spit on muffs....
 

scott hamilton

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Compression is all good. Even after returned motor from shop motor would still barely idle in gear without dying. (idle has never been right but does slightly improve after carb cleaning - which I have done 10 times!)

Just returned from launch. Took it off trailer and ran it.

1. removed air silencer and warmed up motor. Still will not idle down even in neutral. (lean pops)
2. confirmed spark on all 4 with timing light.
3. start Joe Reeves method to restrict air. In neutral, used manual choke to slightly restrict air flow to carb throat. This seemed to smooth out idle.
4. put motor in gear at idle and motor dies. Raise throttle arm to increase rpm, lower throttle arm and quickly put in gear. Before motor dies (no helper) I QUICKLY close manual choke (about halfway) and motor will idle nicely. So, with the manual choke about halfway closed I get good idle in fwd and reverse. I believe this definitively confirms that I am lean at idle.
5. Also, read timing to be 2 deg at idle.

Fuel system (tank and all lines, bulb, pump) are new. I did purchase filter that will be installed but I do not think that dirty passages are the issue (could be wrong).

My plan is to remove, clean and reinstall with all new gaskets.

I would however, like to try smaller idle jets. Anyone have a source for these?

Also, any other ideas? Is Joe Reeves still around on iboats?

Thank you all. I feel like I may be getting close.
 

emdsapmgr

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Sounds as if it is running lean, and a "lean sneeze" seems to confirm that. Usually a complete cleaning of the carbs will correct this problem, as the sneeze is related to a restriction in the idle circuits (passages) of the carbs. I'd be inclined to remove the idle jets and re-clean those carb passages. An aerosol can of Gumout works well. Visually inspect the jets for any restrictions and note the jet size. On that engine, the idles should be 317473, or .030. Check to see the jet is stamped accordingly. It should idle well with that jet. A low idle will also cause idle problems. The idle is set by adjusting the timing, not by any carb adjustment. Set the idle when the boat is floating normally in the lake and is in forward gear. The idle rpm's should be 650-700 rpm's. You can't set it on the trailer. The next size smaller jet is p/n 322776, .029. Are any of the fuel hoses on that engine still original from 1979?
 

WrenchHead

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Reading your last post -- You could be sucking air around the carb mount -- loose carb or bad gasket. You can also suck in air where the throttle and choke shaft are mounted in the carb body. And I once saw a carb with a crack in the carb body, and the engine would only idle with half choke. Smaller idle jets seem to me would give you leaner mixture at idle. Did you say you have adjusted the idle mixture screw(s)?. Maybe vibration has moved the screws.
 

racerone

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I do not believe there are idle mixture screws on the 1979 model carburetors !
 

scott hamilton

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Reading your last post -- You could be sucking air around the carb mount -- loose carb or bad gasket. You can also suck in air where the throttle and choke shaft are mounted in the carb body. And I once saw a carb with a crack in the carb body, and the engine would only idle with half choke. Smaller idle jets seem to me would give you leaner mixture at idle. Did you say you have adjusted the idle mixture screw(s)?. Maybe vibration has moved the screws.

Thanks I will check for those air leaks and new gaskets just to make sure. No mixture screw (I wish). Idle jet is fixed orifice.
 

scott hamilton

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May 28, 2002
Messages
215
Sounds as if it is running lean, and a "lean sneeze" seems to confirm that. Usually a complete cleaning of the carbs will correct this problem, as the sneeze is related to a restriction in the idle circuits (passages) of the carbs. I'd be inclined to remove the idle jets and re-clean those carb passages. An aerosol can of Gumout works well. Visually inspect the jets for any restrictions and note the jet size. On that engine, the idles should be 317473, or .030. Check to see the jet is stamped accordingly. It should idle well with that jet. A low idle will also cause idle problems. The idle is set by adjusting the timing, not by any carb adjustment. Set the idle when the boat is floating normally in the lake and is in forward gear. The idle rpm's should be 650-700 rpm's. You can't set it on the trailer. The next size smaller jet is p/n 322776, .029. Are any of the fuel hoses on that engine still original from 1979?

Thanks. All hoses are new 2 years ago. I plan to re clean everything and replace gaskets (again). Install fuel filter. Check again for more air leaks.

I do think I am at a spot when I ready to try smaller jet to richen up the mixture a bit.

Do you see p/n 322936 for the 0.028 jet? (same carb as the 1979 115 HP???)
 

scott hamilton

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May 28, 2002
Messages
215
Sounds as if it is running lean, and a "lean sneeze" seems to confirm that. Usually a complete cleaning of the carbs will correct this problem, as the sneeze is related to a restriction in the idle circuits (passages) of the carbs. I'd be inclined to remove the idle jets and re-clean those carb passages. An aerosol can of Gumout works well. Visually inspect the jets for any restrictions and note the jet size. On that engine, the idles should be 317473, or .030. Check to see the jet is stamped accordingly. It should idle well with that jet. A low idle will also cause idle problems. The idle is set by adjusting the timing, not by any carb adjustment. Set the idle when the boat is floating normally in the lake and is in forward gear. The idle rpm's should be 650-700 rpm's. You can't set it on the trailer. The next size smaller jet is p/n 322776, .029. Are any of the fuel hoses on that engine still original from 1979?

I must have this backwards! Do I need LARGER idle jet to get more fuel to the idle circuit?

If so, does someone have the 0.031 or 0.032 idle jet PN? Thanks
 

nwcove

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jmo...but going up in idle jet size will probably just mask the real problem. ( as mentioned, its most likely sucking air from somewhere its not supposed to)
 

scott hamilton

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jmo...but going up in idle jet size will probably just mask the real problem. ( as mentioned, its most likely sucking air from somewhere its not supposed to)

Might be but I am out of ideas and I have read some posts saying that a rejet fixed the problem. Apparently these motors are notorious for idle probs.
 

Faztbullet

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Mar 2, 2008
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Low idle timing will cause this also, make sure sync & link is on carbs, test in lake and turn in idle screw till engine is at 1000rpm then put it in gear and it should drop to 650-750- rpms (off trailer)
 

WrenchHead

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Feb 15, 2009
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This may not apply to an outboard but I'll pass it on anyway -- I once had a 1956 Ford pickup with straight six OHV. There was a manual choke knob and cable on the dash. Truck would only run on half choke. I worked on the carb off and on many times but never solved the problem. One day a fellow heard it idling and said the timing was retarder and I should adjust it. I checked the timing and it was retarder a few degrees and so I set it at 4 degrees advanced. That solved the problem. I then realized when I put the carb at half choke it produced more vacuum and the vacuum advance on the distributor moved the timing up and the truck then ran fine. So the problem was the timing and not the carb.
 

racerone

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Cleaned the carburetors 10 times ??------Proves once again that " most carburetor problems turn out to be something else "---Just my opinion.
 

scott hamilton

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I thought I would post the resolution to this problem in case someone reads this in the future. Checked idle timing and it only read 2 degrees. After a bunch of studying I completed a link/synch and set the idle timing to 5 degrees. Got all that as it should be and this motor is running great. So, it was not a fuel issue it was a timing/link/synch problem.

Obviously the shop did not do link/synch as they said they did and as it says on my receipt. They should return some of my money. A moron cold point a timing light and read that it was not within the 4-6 degrees. I assumed I could not figure out how to properly do link/synch and I assumed that since they said they did it then then actually did it. For 4 years it has been 3 degrees in timing and not fuel issue at all.

Thanks for everyone help.
 
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