Evinrude 9.9 run at half choke...

[Stonets]

hi all, got a 1976 Evinrude 9.9. really hard to start, when it finally started, it can only run at higher throttle otherwise has to be half choke and set to rich (2.5 turns or more). It will "cough" if turned to leaner or less choke. I thought it might be somewhere leaked from the Carb, so bought a new carb kit and replace everything (except for the couple metal caps) but it has no change all all. It is got pretty good compression on both cylinder at 116/118. What else could I try here? thanks all!

 

[tomhath]

When you went through the carb did you verify that all the jets and idle circuits are open? I'd go through it again; pry the welch plugs off and make sure the tiny, tiny holes are open, also check the main jet. It sounds like things are clogged up. Also make sure the packing on the adjustment screws aren't leaking air.

 

[boobie]

Check the high speed jet underneath the plug in the bottom of the float bowl. If that's not open, no fuel to any place in the carb.

 

[Stonets]

replaced

 

[Stonets]

replaced the rubber needle seal and it seems easier to start the motor but still it will cough to die when the speed get lower (still well above normal idle speed).

I took the carb off again and opened the welch plugs and plan to use seaform to soak the whole thing overnight tonight. What I noticed though is that both new plugs from the John/Rude kit seem to be very slightly smaller and felt very loose when I tried them on the hole...can I use these plugs with JB weld to seal the edge or am I missing anything here...?

 

[Stonets]

No Title

just compared again, in fact the new plugs are exactly the same size as the old one...I guess I just need to punch them more in...

I found another plastic tiny part from the kit...could anyone tell me where does it go to?

 

[OptsyEagle]

That goes into your slow speed jet. The problem is getting the one that is in there now, out. It is sometimes missed because it is very difficult to see in there. Take a barbed fish hook and bend it straight. Very carefully slide in the fish hook and try to catch that plastic bearing on the barb and pull it out. Be careful with that steel fish hook inside that aluminum carb. Do everything lightly. Now clean out the chamber very well with carb cleaner and blow it out with compressed air. I would do that carb cleaning and compressed air procedure a couple times. Clean out the welch plug area as well and then insert the new needle valve bearing back in and tap in a new welch plug.

 

[Stonets]

thanks all for the help! the motor is idling well! overall is a proper carb cleaning and all rubber parts were too old and everything was restored after the replacement parts from the carb rebuild kit.

 

[scout-j-m]

So do you think the issue was the slow speed plastic part that you mentioned a couple posts ago? I just rebuilt my carb on my 1982 15hp and opted not to replace that piece as not to risk damaging anything.