Confussed what em I doing wrong.. Mercruiser

[mthuirer]

First I will admit I am not a mechanic.. I learn as a go.. I believe I have a 4 cylinder Mercruiser 470? in a 1985 Sea Ray. Last week I changed points and distributor cap and was able to get the engine to run. but now when I place the carb. cap back on and connect the hose.. the engine stalls.. I have posted the pics. Engine will run as long as it is getting open air.. but as soon as I place that carb. cap back on it stalls out. can anyone give me ideas what is happening.. Thanks..

 

[Daver29]

Re: Confussed what em I doing wrong.. Mercruiser

If that is truly the only difference between when it runs and when it doesn't. Then the only thing I can suggest would be to clean the 'carb cap.' Just pull it off and blow if from the inside out with compressed air.. you might also make sure that it isn't interfering with any linkages on the outside or the butterflied on the inside of the carb.

 

[Don S]

Re: Confussed what em I doing wrong.. Mercruiser

You need to clean the flame arrestor (Carb. cap) all those metal fins around the outer ring are probably plugged up so no air will get through. It has to have air flow. It needs the same amount of air as goes through an air filter on a car.

 

[mthuirer]

Re: Confussed what em I doing wrong.. Mercruiser

I guess its the simple things that get over looked.. I will check to make sure its clean..

Also, I think I read somewhere on here about the choke... The butterfly is wide open. I thought I read somewhere where you pump the throttle couple times and that will close the butterfly for auto choke? I have done that and no changes. The butterfly stays wide open no matter what I do.. Is it the Thermostat?