Mercarb rear idle screw slips off cam

[BigRed15]

I have a '93 Larson 170 with a Mercruiser 4.3 V6. It has a Mercarb carbeurator. Twice last summer the idle screw on the rear of the carb slipped off the cam which controls the choke rod, causing the boat to not idle properly. The screw is only touching the edge of the cam. I am wondering if something has been bent so the two do not line up properly. Is there a solution to the problem. I just had the carb rebuilt and a tune up done and they said they could not recreate the problem so, therefore, there is no problem. Anyone have any ideas? My wife is freaked out that it will happen to her when I am not in the boat. Thanks

 

[Don S]

Re: Mercarb rear idle screw slips off cam

Yes, something is bent, the screw should hit the cam about center of the screw.

Pictures would help, can't see it from here.

 

[Don S]

Re: Mercarb rear idle screw slips off cam

Maybe this picture will help.

First, make sure the screw holding the idle cam is tight. (red arrow)
next, you may be able to bend the linkage at the green arrow enough to align the screw with the cam.

 

[BigRed15]

Re: Mercarb rear idle screw slips off cam



Here are a few pictures, hopefully. Thanks a ton for your responses.

 

[Don S]

Re: Mercarb rear idle screw slips off cam

Looks like slightly bending the whole top of the linkage should get to line up perfect.