1981 E70ELCIH - How to adjust the idle rpm?

[mobisware]

The idle seemed fine when I started. I removed the 3 carbs, cleaned them and reinstalled them (as part of regular maintenance). Now the motor seems to run at a much higher rpm at idle. I'm afraid to run it for more than a couple of seconds. I checked the idle set screw but it was already backed out so far that at idle it's not even touching the roller on the carbs linkage.

It looks like there is a solenoid with air and gas lines attached. Not sure what to do with that. It has a grey pin wheel and a red tab, looks like maybe it is just for adjusting fuel/air ratio.

Any tips or related info would be greatly appreciated.

 

[racerone]

The " solenoid thing " is the electric valve for starting the motor and takes the place of choke flappers.---At idle the throttle valves must all be closed , so check that.---And there should be a gap at the throttle roller at idle.---Best not to adjust that at this time.---I do not believe the solenoid thing was installed on 81 model 70 hp , so possibly you have a newer powerhead on it.

 

[mobisware]

No Title

Here's some photos to help explain (since I don't know all of the part names). With the motor off (in neutral), the carbs are closed (first photo) and the throttle roller is not touching the linkage to the carbs (second photo, green circle).

 

[racerone]

I am thinking you have a newer 75 hp block / carburetors.----The screw with the red plastic thingy is an adjustable low speed jet.---The " grey pinwheel " is a cap on a shreader valve and that is used when winterizing with fogging oil.

 

[mobisware]

Thank you for the additional info. But I'm still not sure what I need to do to lower the RPMs.

 

[racerone]

Observe how the throttle arm moves.-----Then see the lower of the 2 screws.--The lower one is the idle stop screw.---------You might have to back that out and also adjust the red thing on the end of the cable to pull the arm back some more.

 

[mobisware]

No Title

I disconnected the throttle cable so I could back out the idle stop screw all the way. It might be hard to see in the photo but the throttle arm does not even touch the idle stop screw anymore. It would not start in this position. I started the motor in the previous idle position, the rpms started to increase so I pushed the throttle arm all the way back as you see in the photo but still the rpms increased like it is going to rev out of control.

 

[mobisware]

No Title

Update:

Ok, if I push backwards firmly on the carb choke link / throttle control lever (see photo) then it will maintain a low rpm idle. But if I let go then the rpms go way up.

 

[mobisware]

I discovered that carb #3's choke plate was not closing all the way. After adjusting two screws on the linkage it now runs great. Thanks everyone.