High Idle

[GerClaire612]

I have a 115hp 1978 evinrude. compression is right at 115 per cylinder. I've rebuilt the carbs, and replaced the water and fuel pump. It runs at 56-57rpm at wot. After wot and i let the gas off and i come to idle it idles at 21 rpm. Now for a minutes it will idle at that and then goes back down to 1000-1100 rpm, and then tries to flood. Any ideas?

 

[mrcj001]

Re: High Idle

Check the throttle cable adjustment.....if out of adjustment you will get a eratic idle.

With the engine not running,push the remote lever to WOT and back to idle a few times and watch the movement on the cam follower at the engine and see if it ends up at the alighnment marks of the cam follower.

 

[GerClaire612]

Re: High Idle

i did that could it be that i got a bad carb kit i've rebilt these carbs before i used the sierra kit before this time i used the mallory kit the motor runs grate at hi rpms but at idle trys to flood and gets slugish on take off or could it be something else any ideas i would appreciate

 

[emdsapmgr]

Re: High Idle

Check the timer base to be sure it is not sticking in an advanced position. It may not be returning to idle timing quickly. On these older units, the grease can start to harden, making the rotation/movement of the timer base slow. You can disconnect the ball joint and see if the timer base moves easily. A thorough cleaning and some fresh white lithium grease may be all that is required.

 

[GerClaire612]

Re: High Idle

i'll do that this weekend would that be the cause of it trying to flood it's self out

 

[jtexas]

Re: High Idle

Not sure what "tries to flood" means.

Did you link & sync after the carb rebuild?
Do the carb throttles stay parallel throughout their range of motion, and close off completely at idle?
Do the choke plates stay completely open except when the choke is engaged?
Are all the plastic grommets holding the linkage rods intact (they start to deteriorate after 30 years or so)?

 

[GerClaire612]

Re: High Idle

i got a new carb kit motor runs grate now.jtexas flooding means plugs are fouling out to much gas