Thread: STILL having start up issues

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I'm still having problems starting up my BB chev. If it's around 40 outside I have to pump the gas pedal 4 or 5 times to spray the intake before trying to start it. If I do that just the right amount of times depending on temperature it will start. Sometimes if I stop at a gas station when it's fully warmed it starts, sometimes not. I never know if I should give it a squirt or two, whether I should choke it, or just turn the key when it's warm.
If I guess wrong and it doesn't fire up then it is even harder to get it to fire on the next crank.
The cam is a 226 @ .050 hyd., I'm running 15 degrees static advance with vacuum that brings it up another 10.

I'm starting to get really frustrated, I don't know what I'm doing wrong or what I set up wrong. I've been working on this thing EVERY day for the past year and a half and now it's finally done and I can't even enjoy driving it because I'm constantly worrying about whether or not it's gonna start when I park it.
I might as well just flip a coin.

the mixture thing is definitely a part of the problem. I'll have the idle set great and then it will be 15 degrees warmer one day and the thing will be all screwed up.

I also just bought a book on ignition systems, I suspect that may be a culprit too.

Hopefully by spring I'll have it figured out.

what carb are you running on the motor and how old is it?

it's an edelbrock thunder series 650 cfm.
it's bran new, the motor isn't, but the cylinders looked fine.

it's a manual choke, is that what makes all the difference? I know I've used carbureted vehicles and boats that had electric chokes and they would start up first try every time, no pedal pumping or anything like that.
Could a slightly longer cam make that much difference?

Could the fact that I'm using manifold vacuum and not ported vacuum be affecting this problem?

I feel like the plugs would have a better chance at lighting the mixture if it was a little later in the compression stroke so it would be more compressed at ignition.
I'm not really basing that on anything though.

I agree that the timing seems way off. Have you had a good carb shop look at it? Sometimes when you've been looking at it that long, you get blind to the problem. Sounds like getting a second opinion from someone who can look at it is going to be money well spent. I'd take it in before you lose confidence in it. Good luck.

yeah, the baseline timing with no vacuum is 15. It seemed to idle much better the more timing I gave it.
Would the vacuum advance be kicking in while it is just cranking, or wouldn't that build enough vacuum to do it?

Also, do coils decay over time?

yeah thats too advanced... that'll cause startup issues.... if it seems to idle a little rough, try adjusting your vaccum advance, a lil.... and yes coils can decay over time, but ussually they dont... ussually its from being bumped around and from getting overvolted... the inside of a coil is thousands of spools of wire that cause a magnetic field.....

as I read in my ignition system book I did some tests on coil and wire resistance. The book says coil primary side resistance should be less then 1 ohm, secondary side could be over 1000 ohms.
My primary side is about .8 or .9 ohms and the secondary side is over 4000 ohms. It is an msd blaster 2, I using an MSD 6AL box with it.

I measured the resistance of my coil to cap wire, which is about a foot long, and it measured 1300 ohms. I measured another arbitrary plug wire just to get a reference, (#2 cylinder wire), and it was about 400 ohms.

I haven't gotten very far in the book yet but I don't think my coil should have that much secondary resistance, and I also don't think the coil wire should have that much either.

welp, just went to msd's site and apparently that coil is supposed to have those resistances.
that plug wire still seems sketchy.

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