runs hard after trollhole carb and dizzy install

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WarToy2u

WarToy2u

10 Year
Joined
May 10, 2012
Threads
9
Messages
60
I just installed my new trollhole carb and elec dizzy on my 40 and it isn't running right. I had a 38/38 weber and a aftermarket Delco GM dizzy on it before and it was running well. I switched because of some issues I was having with the dizzy and decided to get both from Marshall. After hooking everything up it will start but has a rough idle. When I give it gas it struggles and sometimes sputters. I have the wire from the carb hooked up to the positive side of the coil. The timing is right on the BB while it idles.

Like I said before, it starts and runs but sounds rough and not drivable. Any insight would be greatly appreciated!
 
Lots of questions: First, when you first start it up, you need choke. Did you apply that and let it warm up? When it warms up and the choke is off, what is the idle speed? Do you have the vac advance line disconnected and plugged when you do the timing? Did you adjust the idle mixture and speed or just leave them as shipped? What is the vac advance line connected to?
 
Casey- I have checked and am getting spark to each plug. In the window it is just below half full.

edwjmcgrath- I did not have vac lines disconnected and blocked, I had it hooked up to the carb while I was doing the timing. Should I re-do it with them blocked. Vac line from dizzy is connected to carb.


Scott- I thought about the dizzy being one tooth off, I wonder which direction I should go, left or right.

Marshall- I'm on the west coast, what's our time difference to you? I'll give you a call.

Thanks guys! :bounce:
 
Vacuum advance to distributor should be disconnected and capped at dizzy when setting the timing. I have a trollhole carb. Marshall had me set timing a bit advanced at 10 degrees BTDC. Talk to him. He will get you going.
 
WarToy2u said:
Scott- I thought about the dizzy being one tooth off, I wonder which direction I should go, left or right.

Thanks guys! :bounce:
Click to expand...

Take it all the way out and start over, making sure that the rotor is pointing at #4 cylinder when the distributor is seated all the way down. It's going to want to rotate when the oil pump gear engages. Compensate for that as you line it up.
 
If plug #1 fires on the BB, and you have enough room to rotate the dizzy, there's no need to pull the dizzy to move it one tooth...




WarToy2u said:
The timing is right on the BB while it idles.
Click to expand...

WarToy2u said:
Scott- I thought about the dizzy being one tooth off, I wonder which direction I should go, left or right.
Click to expand...
 
I agree. If you think that the problem is simply timing, loosen up the dissy clamp and give it a try each direction and see if it runs better by ear. If you can't turn it any further, move the wires. Once you get it running smoothly, then adjust the idle speed to spec. THEN you can time it with the timing light. If the idle speed increases after timing, readjust the idle speed and redo the timing until you get it right.

The timing light is not very useful unless you're running at 650ish idle and you've got the vac line(s) disconnected and plugged. If you've got the idle cranked up because it's misfiring all over the place, the centrifugal advance and vac advance will make your timing light readings meaningless.
 
Thanks guys, Marshall and I missed each others calls so I just pulled the dizzy before getting the updated responses. It didn't work and I can see why switching plug wires may have been a better idea. It still runs the same after getting it put back together. I feel like it has to be the timing but have to wait till Monday or Tuesday to play with it again. All the advise is much appreciated.
 
WarToy2u said:
Marshall and I missed each others calls
Click to expand...


Good, gives you another day to triple-check all the basics before he points it out to you and makes you feel foolish...check the firing order of the plug wires on the dizzy cap, do you have the vacuum line to the correct port on the carb? Do you have points in that dizzy? re-check the gap. Etc...
 
When I was going threw this I had two separate PM,s telling me to open my carb up and look in the float bowl. I would make sure it was clean and you don't have a plugged jet .
 
Sounds like a vacuum leak to me, or the accelerator pump.
 
While you cannot compare the two 'apples to apples', what was the timing on the GM dizzy set at?
 
I've been swamped at work and haven't been in the garage. I tried to call Marshall but got voicemail. Will try again soon, this is killing me!
 
Also I noticed a small hole in the intake manifold between the carb and the valve cover. Is that for anything in particular?
 
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