350 wont start unless jumped and popping out of the carb ONLY at start up!

[ruedger455]

Its the original motor the only thing thats been changed is it has a distributor with a vacuum advance and he put a mild rv cam in it. It didnt start doing this till this week. But its always been hard to start on initial start up.

 

[HotRodPC]

Its the original motor the only thing thats been changed is it has a distributor with a vacuum advance and he put a mild rv cam in it. It didnt start doing this till this week. But its always been hard to start on initial start up.

Also be looking for Vacuum leaks. Start it up, and spray carb cleaner, or starting fluid around the base of the carb and where the intake meets the heads. You can use WD-40 too, but it doesn't discipate near as fast and leaves a bit of a mess.

Could just be carb issues. So hard to tell sometimes when not seeing it in person.

 

[HotRodPC]

Something else that just dawned on me, you've mentioned swapping a Eddy for the Holley. So does this mean it has a Holley on it now? And you've mentioned popping or backfiring out the carb. Holley's not like backfires out the carb. It only takes 1 time sometimes to blow the power valve in the carb. Chances are, you'll end up needing a power valve put in the carb when find this hard start and idling issue. Power Valve shouldn't affect the idle though to the best of my recallection. I'm still leaing toward a worn or weak accelerator pump too. Just hard to say for sure by your desicription and not seeing it or hearing it myself.

 

[Boone83K10]

Unless the holley carb is older than 1992, it has power valve blowout protection.

 

[HotRodPC]

Unless the holley carb is older than 1992, it has power valve blowout protection.

Nice, they finally did something about that. That is one of the things that ran me away from Holley in the mid to late 80's. I have about 4 of those carbs. 2 of them are List 1850-2 and -3, which are 600 Vac Secondaries with manual choke. Very simple and effective carbs, but not very reliable.

 

[ruedger455]

It has a 1405 eddy right now. I got it running decently at 18°. And i adjusted the idle mixture screws. The right side was only turned out a half turn. The left was 4 turns out so i turned them both in all the way and turned them both back out 4 turns. And its running better.

 

[Boone83K10]

Get you a vacuum gauge and tune to highest vacuum while keeping the screws at the same amount of turns in/out, also keep the idle rpm the same.

 

[ruedger455]

Well i went out today in this cold ass michigan weather and i checked my timing. because i started the truck this morning without the air filter on and my carb was on fire. So i did alittle research and it said i should advance my timing Well i advanced it quite a bit and it no longer pops out of the carb and it doesnt hesitate when i get on it qui kly and i noticed my exhaust got quieter! And i adjusted the carb. 2 and a half turns out from full lean on both mixture screws and its idleing good now i just gotta drive it which i will do in a bit. Before i adjusted the carb, it sounded like someone was beating on a wood door with your hand. But feintly what could that be?

 

[89Suburban]

Good job, keep tinkering with it and you will get it!

 

[ruedger455]

Yea im gonna wait till morning to see if it will fire up cause thats when i have most of my problems.

 

[Boone83K10]

Detonation

 

[ruedger455]

Should i retard it alittle till it doesnt do that?

 

[ruedger455]

It doesnt ping at all so i figured it was ok.

 

[ruedger455]

Well i think i explained that wrong lol it doesnt sound like a knocking at all. It sounds like a slight bass vibration like in hoopty car.lol

 

[r.booser]

I figured adjusting it would work, especially since it was the same for me. Glad you got it figured out. I'd play with it till you have it just the way you like it. I still have to play with mine a little but I also have to replace my tank.....the never ending story!