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Discussion Starter #1
hello all i know i posted a previous thread but i noticed two additional problems when i pulled the carb of. Unscrewed the accelerator pumps and the back one the one that was not leaking i noticed a little orange flat rubber circle type device stuck to the bottom of each of the inside of the accelerator pumps on the 4150 750 holly carbs. the back one that was not leaking the rubber orange circle had a little tear in it and was pulling away a little from the floor of the accelerator pump. Do i have to replace this part and if so what is it...the front one is ok but the diaphram was twisted up and shot in that one. Also the mating gasket for the carb to manifold got a little wet with gas but it has no tears and the gas dried out is it ok to reuse it again? thanks in advance for responses
 

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Those are check valves and yes, you have to replace them if they are damaged or you won't get the proper shot from the pump. You can use the base gasket again, just put it back in the same position it came off.
 

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Discussion Starter #3 (Edited)
ok i am getting fustrated here is there a special way to pop these check valves back in...there is a lip on it in the middle and i cannot get it to squeeze and seat back in the hole...the lip part wont squash through and i dont want to tear it....is it ok to use a screw driver or something to pry it in ....this is my first time replacing one of these ......help its ok i tapped it in with a dull head of a screwdriver
 

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My experience tells me that a pair of needle nose pliers, used to pull the check valve through is the best way to do it. I'm 99% sure you will never be able to push it through.
 

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Discussion Starter #5
My experience tells me that a pair of needle nose pliers, used to pull the check valve through is the best way to do it. I'm 99% sure you will never be able to push it through.
hey woodsnake would this not require taking of the float bowl though to pull them through...somehow i got it to go through without doing this ......have another problem though got everything back together and wont start ...i am giving it gas and no gas is going into fuel bowl... one thing i noticed is that the acelerator pump handles has lots of slack in them and are not touching lever arm sercurely... am i suppose to readjust these again to make them snug every time i change diaphram and check valve.. could this be my problem
 

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You need to make sure that the diaphragm goes all the way through, and over the 'hump' on the stem of the diaphragm..Taking the float out would make it a lot easier.
 

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Speaking of the orange, rubber "umbrella" style check valves....I think they work much better than the ball bearing style check valve in the newer Holleys. I don't think they have as much of a delay in getting the pump shot flowing. The new Summit carbs have these older "umbrella" check valves in them and I can run the black Holley pump cam instead of the green one that came on the carb without ANY hesitation when shifting my '85 Mustang GT. The green pump cam has a more agressive ramp than the black one, so I'm actually using slightly less fuel with each pump shot.

Make sure you adjust the pump arm bolt/spring combination with the car warm and the choke completely disengaged. Adjust it just enough to take out ALL the slack. Holley's instructions are a little confusing on this because they say to use feeler gages when the throttle is held wide open, blah, blah, blah. Just ignore all that and take out all the slack. If the car is cold, choke fully/partially engaged, then the fast idle screw is sitting on the fast idle cam, cracking the throttle plates open slightly. If you adjust it like this, you'll have too much of a gap between the accelerator pump arm and the bolt/spring combintation when the choke disengages and comes off the fast idle cam.
 
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