krisner89

Got my car to the point where I could start pushing it to see what it'll do. Oil leaks and overheating problems etc... Got a bad stumble, cut out problem. Cruising or half throttle take offs it runs good. If I mash it past half throttle whether at complete stop or going 50 mph (2000 rpm) it cuts out and eventually cuts back in and runs good to 6000 rpm and run through the gears with no more cutting out. Its just that initial push down on the pedal it cuts out. I moved the linkage for the accelerator pump(hole closest to carb) so it gives a bigger squirt of fuel and it helped but still cuts out some.

Am I on the right path here since it helped the stumble. Should I get bigger accelerator pump nozzles first or is it something else.

This carb and dizzy worked great last summer on a close to stock 355. Have since upgraded to a bigger .060 over 350 with bigger cam, aluminum heads,rpm intake, etc... Oh and a 3000 stall.

midias

The 1405 should run most 350s no problem even ones with decent cams with stock jets and rods. Sounds like more of a timing issue. Generally start with the idle circuit and a vac gauge the follow the tuning manual.

http://www.edelbrock.com/automotive/...ers-manual.pdf

If it cuts when you mash I would first adjust the accelerator pump through the 3 holes. Then replace the springs for the rods based on idle vac or guess work.

krisner89

ok thanks midias. I was thinking timing too. I got 34 degrees total timing. I played with vacuum advance adjustment allen and even unhooked it from dizzy once with no signs of improvement with stumble.

Thats why I'm thinking its carb related. Idle circuit is adjusted right per manual and idle screw is set to idle around 800 rpm. Adjusted accelerator pump to top hole and it helped. Doesn't completely kill the engine for few seconds it just stumbles now. Ill start shopping for a metering rod spring kit and a new accelerator pump. Its a older carb and new pump wouldn't hurt. Ill post after I try those to tell if it cured it. thanks again

midias

This is the spring kit you need. Generally you pick a spring value 1/2 of idle vacuum.

http://store.edelbrock.com/step-upsp...ssortment.aspx

If you are changing the pump get a new airhorn gasket while you are ordering things. You may also want to check and adjust the floats while you have the top off. There is also an adjustment for the pump arm. IIRC you want the top of the pump 9/16 above the top of the carb but double check that.

-=Z28=-

iTrader: (3)

There is some really good videos on youtube on adjusting your carb to perfection. Pretty sure there is a video for just about every carb manufacture. when it comes time to do mine, thats what im going to do.. FYI..

krisner89

Was thinking of edelbrock 1479 for future fine tuning. Got new pump and gaskets ordered now. Tuning kit kind of expensive. Debating now to get just the springs or the whole spring,jet, rod tuning kit.

krisner89

I've learned alot from those. Not just carbs but everything in life that needs fixed. We got it made these days. Just type and click. Moneys tight and just want to make sure I don't spend on what isn't going to help.

-=Z28=-

iTrader: (3)

Totally. I still like to tinker and find stuff out myself but I fear that everyone is just typing/searching and not tinkering which is becoming a dying trade. Everyone it seems these days is "throw it out and buy new" My Father would kill me....

Yes, those videos are pretty nice and in depth.

midias

For now I would start with just the spring kit. After that you might be able to finish the fine tuning with just some rods.

krisner89

Still waiting on springs to get here. But have a few other issues I've came across tinkering with fuel system.



1. Looking at spring kit there are different colors AND SIZES for different vacuum amounts. I took mine out of carb just to look at and one is a faded bluish color and the other is plain silver color. Both look identical in size and feel about the same compression. Can they fade or change color over time.

2. I have hooked 3 fuel pressure gauges between carb and mechanical fuel pump and cant get a accurate reading. They all bounce up and down. Worse at idle. As rpm increases they smooth out some but still unreadable. Here is the thread on that.

https://www.thirdgen.org/forums/tech...-pressure.html

midias

The paint on the springs comes off the moment they touch gas don't worry about that.

krisner89

Figured I would post up an update on progress. I changed orange springs to pink springs and helped but still had small stumble. Have idle vacuum of 8-10 in. so decided not to go further with springs. I then changed metering rods from stock .070 x.047 to .068 x.042. Keep in mind accelerator pump is on max setting. Stumble barely there now. Spark Plugs are white so still lean. Going to bigger primary jets now. Its getting better and better the more fuel I add.

krisner89

Did a WOT wholeshot at buddies house and had him look to see if any black smoke came out of exhaust. He saw none. Has to be a lean condition right.