Chrysler 35 HP - Sporadic Miss at Idle

[SeaStar69]

With thanks to the responses on this forum, I was able to source parts and get my 1969 Chrysler 35HP running. I did a full rebuild on the carb - everything is new except for the float, put a new diapragm in the fuel pump, new plugs and installed new Fairbanks/Morse points and condensors. I fired it up today with fresh gas and I was getting an occaisional miss at idle. It smooths out when I put it in gear and seems to run OK at higher revs. The best I was able to do was bump up the idle just slightly from fully closed and adjust the mixture screw to 1 turn out. The miss is still there, bit it's barely noticeable. Is this typical of an old 2 cycle engine?

Thanks, Jim

 

[wickware]

Re: Chrysler 35 HP - Sporadic Miss at Idle

Good Point that this could be normal at idle vs Higher. I always seem to get a cough idling on my 1970 35 HP Chrysler vs smooth running above idling. Since you were just in the carb, did the needle or seat have rubber to seal them? jow

 

[fucawi]

Re: Chrysler 35 HP - Sporadic Miss at Idle

One turn out on the idle is a bit out from standard though by no means " incorrect " ....did you set it about 1 1/2 and turn it in until it missed /coughed and then back a touch? I think the rubber seat refered to is the needle valve seat in the carburetter...If that was not seating you would have fuel leaking out the carb so I diagnoe its ok .

 

[jerryjerry05]

Re: Chrysler 35 HP - Sporadic Miss at Idle

Setting the air screw can make the miss go away.Start at the base setting.Motor warm and in gear, 1 and 1/4 turns out,then in till it coughs and then out 1/2 turn.Then as it runs(still in the water and in gear) adjust the screw 1/16th turn at a time.Never going more than 1/4 turn in either direction.
And sometimes a Chrysler/Force will miss no matter what you do.J

 

[fucawi]

Re: Chrysler 35 HP - Sporadic Miss at Idle

A contact system is said to miss 2 % of the time which is why we have electronic ignition on our cars so we dont send unburnt mixture down the exhaust ....