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Discussion Starter #1
So in my reading I think I'm understanding that the surge is caused by being fat at idle. If that is the case then will the surge be worse the fatter it is? I don't really care if it's there it just seems to be real bad on mine. Bottom side is about 800 and the top is over 2000 with the boat out of gear. This is a blown alky motor. Wags or Fiat or someone can you please help me calm this thing down? It got a bug catcher and a 110 pump. Thank you
 

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There are just so many variables as to plumbing, main jets, jet cans, spool that is in it, blower %, compression, motor size, ignition and how everything relates.

#1. Is you ignition advance locked out? If not it should be. Is there play between the dist gear and the cam gear? Dist gear worn? If so you will never get the surge calmed down as the timing is moving around. Mags are worse yet. Get the timing locked....and tight....at 34 degrees.

#2. Main jet can. Make sure the spring is very light that is in there with no shims. You should be able to remove the jet can and shake it hard and hear it rattle. Only couple lbs pressure.

#3. Check that the butterfly's are open to about .005 to .010 with a feeler gauge...no more than .010.

Fire the thing and warm it up.
Try leaning the barrel valve a few flats at a time to get the surge to go away. DO NOT WACK THE THROTTLE.
Lean it.......then crack the throttle open and raise the rpm and let it clean out and then back to idle.
Continue to do that carefully till the surge is not very noticeable.
Now crack the throttle and if the motor hesitates the least then you are too lean on barrel and have to richen the barrel.

Remember you have to clean this thing out ever so often as you are playing with it.
Be sure there is some surge. Most time you are gonna end up with some. Richen the barrel to get surge....lean to get away from surge.

When you think you are close you can wack the throttle. All you are doing there is seeing if there is enough fuel to keep from a hesitation. Remember it may not hesitate on the trailer with no load but it damn sure might when it has a load. So when in doubt...richen the barrel.

Idle speed is controlled by how far the butterflys are open. Sometimes playing with the butterflys and the barrel you can get the medium you want.
Good luck.
 

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" #2. Main jet can. Make sure the spring is very light that is in there with no shims. You should be able to remove the jet can and shake it hard and hear it rattle. Only couple lbs pressure. "

I actually have better luck with about 8-9 #'s in the idle check ?

Seems to hold a little more constant pressure in the system that way,,, just a suggestion !

Isn't a 110 pump like 13 gpm ????

Thats alot of power you got there if it is !
 

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Discussion Starter #4
Ok here goes 470" 8-71 15% od timing locked at 34. Main pill 150 hat nozzles only with 58 in the front 6 and 62 in the rear. Idle set at .008" Mallory super mag 2 main can rattles like you said. -16 to the pump. -8 pump to BV. Anything I forgot? Thank you
 

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Enderle's famous fits all 58 nozzles. LOL

We got a little motor...low compression.....big pump, big nozzles, and the super mag kinda aggravates it too (because the lock out winds up).

I think it would be well worth it to change the nozzles to 48's. Low compression could prolly do smaller but 48's ought to be safe. That will get the line pressure up a bit too.

You can try it without changing the nozzles but they are really too big especially with that compression.
You really ought to to go to a smaller pump but you can get by what you have.

You oughta have a high speed in that deal too. Prolly 70 pill anyway.
 

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Enderle's famous fits all 58 nozzles. LOL

We got a little motor...low compression.....big pump, big nozzles, and the super mag kinda aggravates it too (because the lock out winds up).

I think it would be well worth it to change the nozzles to 48's. Low compression could prolly do smaller but 48's ought to be safe. That will get the line pressure up a bit too.

You can try it without changing the nozzles but they are really too big especially with that compression.
You really ought to to go to a smaller pump but you can get by what you have.

You oughta have a high speed in that deal too. Prolly 70 pill anyway.
You lost me at Hello. Damn sprinkler fitters. :wink2:

Seriously Fiat, what do you mean by the Mallory lock out winds up? At an idle?



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The lockout is a rubbery/plastic gizmo poorly designed.
On the bottom of the mag generator is either a 2 or 4 pin drive. These pins are about the size of 3/16 roll
pin. These 2 or 4 (depending on what you have....they came both ways) sit into this lock out piece.
There are 2 pins also on the base drive.
So it is not a solid piece...it flexes (winds up) and the timing moves around some. Throw a timing light on one and you will see it.
I have made solid ones out of aluminum but eventually that wants to break the pins off the drive base. The mags are hard to turn. Mag II not as bad as the Mag III's and up.
Course with some dist gear wear and a motor that tends to surge anyway....you can see it aggravates it.
Not such a bad deal in a boat but plays hell with trying to stage a drag car on the line.
I'll see if I can drum up a picture.

Here is a 4 pin lockout. Flexy flyer that it is. LOL
Products Used Mallory advance lock out diamond
 

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The lockout is a rubbery/plastic gizmo poorly designed.
On the bottom of the mag generator is either a 2 or 4 pin drive. These pins are about the size of 3/16 roll
pin. These 2 or 4 (depending on what you have....they came both ways) sit into this lock out piece.
There are 2 pins also on the base drive.
So it is not a solid piece...it flexes (winds up) and the timing moves around some. Throw a timing light on one and you will see it.
I have made solid ones out of aluminum but eventually that wants to break the pins off the drive base. The mags are hard to turn. Mag II not as bad as the Mag III's and up.
Course with some dist gear wear and a motor that tends to surge anyway....you can see it aggravates it.
Not such a bad deal in a boat but plays hell with trying to stage a drag car on the line.
I'll see if I can drum up a picture.
I get it. Not much different than slop on a advance mechanism in many dizzies. Slop anywhere in the ignition plays havoc. There is a reason crank triggers have become so popular with the electronic guys.
Thanks, I thought it might be something in the way the Mallory makes juice, more than a mechanical issue.



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here is my set up..
512 bbc
9.78 c/r
10-71 @ 14.3 od
big & ugly w/k valve,58's squared , 80 pump, 85 pill
3 amp mag locked..34*-36*
 

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Yeah.
Now a vertex uses a plastic plate for a lockout right below the generator. Those stay real solid. But then a vertex is easier to turn but puts out less spark too. And spark duration is shorter.
 

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Ok here goes 470" 8-71 15% od timing locked at 34. Main pill 150 hat nozzles only with 58 in the front 6 and 62 in the rear. Idle set at .008" Mallory super mag 2 main can rattles like you said. -16 to the pump. -8 pump to BV. Anything I forgot? Thank you
Does it have a pump sizer in it ?
Any other jet cans ?

Without flowed parts this is a guess ?
110 pump 13.4 gpm
6x58
2x62
.150 main

13 lbs of boost


Has lots of fuel pressure !!!!!!
 

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Discussion Starter #18
Boat came with a high speed 22# spring and a 145 pill fiat by all means if you have a tune in mind that will clean this thing up and not burn to the ground I'm all ears and have good vibrations on speed dial lol thanks for the help
 

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Discussion Starter #19
According to the dyno sheet max fuel psi was 68# at 7100 and the motor started to fall off at that point
 
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