choke thermostat problem

[cruiserfj]

I have a 1995 mercruiser 4.3 lx with 4 bbl webber carb.choke does not seem to operate correctly. does not close all the way when cold(hard start cold) and does not open all the way warm(boggs on full throttle).tried to find a new choke thermostat , possible part #66203 but part no longer available. what else can I use?

 

[gm280]

Re: choke thermostat problem

Is this a divorced choke setup or an electrical operated setup? If it is a divorced setup, is there any options for the connecting linkage to allow for further throw? If it is an electric choke, have you verified that there is the correct voltage reaching the unit. If there are some compromised connections, the voltage, and therefore the current, will not heat it enough to make it work properly. Check for both supply and ground connections before discarding it. If it is operated off heat from the exhaust then it could be a setting adjustment. The has to be a reason for a factory choke to stop working properly. Find out why. There are rather simple in their design and usage.

 

[cruiserfj]

Re: choke thermostat problem

it is a divorced set up. looks like the linkage could be bent for further throw . heated spring not expanding and contracting properly, probably burnt out

 

[gm280]

Re: choke thermostat problem

Before you place it, take it out and clean it with some carb spray and try it again. Some of those springs are a ribbon type and get crud in them and that changes their expansion and contraction capabilities. Just a suggestion...

 

[dubs283]

Re: choke thermostat problem

heated spring not expanding and contracting properly, probably burnt out

is the coil spring exposed?? - there should be a shroud over it to contain/direct the heat from the intake manifold

is the engine actually coming up to temp?? - verify with ir temp gun