D.U.I Installed, now no start (1 Viewer)

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Hey all,

I installed the DUI this afternoon, and now the engine won't start. I had an HEI distributor installed before, an older Remy Delco, and I wanted to update it.

Procedure: hand cranked the motor to TDC (the line right before the BB). I took a picture (posted) of the rotor location.

I installed the new DUI, with the rotor facing in the exact same position, put the wires back in the correct sequence. I got to start...nothing.
I got one backfire (through the carb) once.

I checked for spark, it has it, doesn't look overwhelmingly strong, but I don't know what the benchmark is.

I've watched videos on different installs, read the directions.

Should I follow the FSM and try to install the DUI following those procedures?

Thanks in advance.
IMG_20200919_145137021_HDR.jpg

IMG_20200919_145227936_HDR.jpg
 
Joined
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I thought I was, the rotor was facing at the old #1 spark plug before I took it off.

I thought about putting a screwdriver as a reference into the #1 cylinder from the spark plug hole, but got a bit weary about doing that.
 

1911

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Are you at tdc on the compression stroke? You are probably 180 out.

This. There are two TDC on a four-stroke engine; one on the compression stroke and one on the exhaust stroke. Put a piece of toilet paper in the #1 spark plug hole; when you get to the compression stroke the piston will blow it out. When that happens, turn the engine slowly until you get the BB on the flywheel.
 
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Okay.

If the rotor was facing the old #1 spark plug, could it have been on the exhaust stroke? Honest curiousity.
 

1911

chupacabra
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Okay.

If the rotor was facing the old #1 spark plug, could it have been on the exhaust stroke? Honest curiousity.

The distributor could be stabbed in to make that so, but is has nothing to do with when the compression stroke is. The distributor can be stabbed in any old way, as long as it engages the oil pump and the vacuum advancer doesn't interfere with the pushrod cover.

Pull the dizzy out, definitively find the compression stroke of the #1 cylinder, line up the mark on the flywheel, turn the oil pump close to where the dizzy will engage it when stabbed, then stab the dizzy in the cam gear (and oil pump) where it will just be firing the #1 cylinder. On a stock dizzy, this would be with the dizzy rotor pointing in between #4 and #5 spark plug, but I don't know about your DUI dizzy.
 
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okay. I'll give that a go. So disappointing when you think you've done your research, feel prepared, and then utterly let down.
 
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The distributor could be stabbed in to make that so, but is has nothing to do with when the compression stroke is. The distributor can be stabbed in any old way, as long as it engages the oil pump and the vacuum advancer doesn't interfere with the pushrod cover.

Pull the dizzy out, definitively find the compression stroke of the #1 cylinder, line up the mark on the flywheel, turn the oil pump close to where the dizzy will engage it when stabbed, then stab the dizzy in the cam gear (and oil pump) where it will just be firing the #1 cylinder. On a stock dizzy, this would be with the dizzy rotor pointing in between #4 and #5 spark plug, but I don't know about your DUI dizzy.
Okay, I got to TDC on the compression stroke.

Still won't fire, but I'm now getting back fires up through the carb.

Thoughts?
 

whitey45

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Double check your firing order and direction of rotation( easy to wire backwards. Also you can move the distributor while cranking to see if you are too advanced or retarded.
 
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Okay, so I took a piece of copper that I bent to get down into the #1 cylinder, it seems like I was 180 out. So I took what was the #6 plug on the dizzy and switched it to 1 and wired accordingly, 153624. It started for a minute then died. I'll take that as a small victory for the day.

Was that the right thought process to reverse the 1 and 6 on the dizzy?
 

lcwizard

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You can stick your finger over the spark plug hole while you turn the engine. On the compression stroke you'll feel the air push past your finger. Or you can buy a compression stroke whistle. They thread into the spark plug hole and whistle as the piston comes to the compression stroke
 
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where did you source that distributor?
I got the dizzy from Summit Racing.

I got it going, set the initial timing to 12 btdc.

Should I try to set total timing at 2500 rmps?

I adjusted the carb using the lean drop method with a vacuum gauge. I'm reading 18 at 650, but the needle wanders +/- .5 each way.

Also, the RMPs vary a bit from 640ish-660ish, is that normal for the rpms to move a bit?

It still smells a bit "rich" (i know that it's not possible to tell it's rich by nose).

I'm at the point with the idle mixture screw where if I turn it in or out my vacuum drops.

If I pull the idle solenoid wire out, it stalls out, so that's working proper (I think, have I mentioned I know nothing).

I couldn't find any vacuum leaks by spraying carb cleaner around the manifold or base of the carb. I'm thinking about doing this technique.

thanks in advance.

judge
 

lcwizard

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So it's a new Davis Unified?. The pics are showing an old Delco cap. I was hoping you didn't just slap in a GM straight six distributor from
a junkyard. That you tube technique is locating an exhaust leak. That's not looking for a vacuum ( Intake) leak.
Start from scratch. Locate #1 top dead center on the compression stroke to locate the #1 wire. Double check the sequence of the other five.
Don't assume you hooked it up right the first time. Also, don't assume you have an operable distributor. You won't be the first to get a Davis
unit that doesn't work. I've had two. Look for contact marks on the underside of the cap. I had a new davis that was making contact between
the rotor and cap. I had another that threw a weight off
 
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No that was the old unit on it. I got it dialed in and the advance set.

I'm still having a lot of flat spots in my acceleration.

It's a trollhole carb, that i feel like hasn't run well since I put it in, always flat at spots.

I took the top off the carb and noticed there was a bunch of gunk in the bowl. Cleaned it out, took some parts off, cleaned it with carb cleaner, blew it out with compressed air. Put it back together. It's running a bit better, but now well. Won't start, even when hot, without a 1/2 choke.

Vacuum is better, with almost no flutter.

The thing that bothers me is that when I set the idle, it's fine, I step on the peddle, and it won't return to idle. I've found that I have to manually press down on the accelerator pump arm to get it to actual rest on the idle screw.


My thought is that the carb is out, gunked up, or something.

I've been leaning towards a efi. I kinda just want to enjoy the 40, I don't want to spend all my time tweaking this, tweaking that, and not feeling confident about going out for a drive with the family.

thoughts?
 

whitey45

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Troll hole carbs have had issues in the past. FWIW, I thought for $79 on eBay, why not try a knock off Chinese carb. Well, I’m running 2 on a couple of cruisers and they have been flawless!!
 

Steamer

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The thing that bothers me is that when I set the idle, it's fine, I step on the peddle, and it won't return to idle. I've found that I have to manually press down on the accelerator pump arm to get it to actual rest on the idle screw.
So it's gotta be either the carb or the pedal linkage causing that hang up. I'd disconnect the the linkage temporarily, and operate the carb manually to see if it acts the same.

And just to mention even though you’re beyond it now, when pulling and replacing a distributor on an engine that is running ok, if you replace it with the rotor pointing in the exact same position as the previous rotor (as you did) and the wires are configured the same, there’s no way it can be 180° out so long as the engine didn’t move in the middle of the swap. You don’t even need to bother putting the engine on TDC. No matter where the engine is at on rotation, just have the rotor end up in the same place as the previous one and it’s good to go except for maybe just a few degrees error from eyeballing it. However, if the engine gets moved with the dizzy out, then you will need to do the process as described in the FSM.
 

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