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520 hesitates / fuel issue?


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#1 Droski

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Posted 08 September 2016 - 04:48 PM

hello

 

i have a 1966 520 , it recently started hesitating/ jerking

like its not getting enough gas. it will jerk at low and high speeds

 

i already replaced the fuel filters

has anyone had similar issues?

 



#2 racerx

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Posted 08 September 2016 - 05:13 PM

Does the 520 have a carb with a sight glass? If so what is the level? You can also be running lean? What is the color of your spark plugs? Is your rpm steady at idle?

#3 racerx

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Posted 08 September 2016 - 05:14 PM

Also your choke can be stuck

#4 kelowg

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Posted 08 September 2016 - 05:43 PM

Water in the fuel? Clogged tank pickup tube/line?



#5 datzenmike

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Posted 08 September 2016 - 05:57 PM

Spark or fuel.

 

Fuel

Next time it's acting up get the clutch in and the key off ASAP and carefully pull over. Check the window on the front of the carb. If full of gas it at least getting it delivered. For now, assume that it's not the gas

 

Spark

Check the points. Are they worn or burnt, pitted? File them or replace and set the gap 0.018-0.022". Look for loose connections on the wires to them and on the coil and ballast resistor. Now inspect the distributor cap inside for dampness. Look for wear or corrosion on the terminals inside. Inspect the rotor while the cap is off. Now look at the plug wires and last the spark plugs. If in doubt replace them with new ones. Electricity will ALWAYS look for the easiest path to ground. So you want a well insulated ignition system where the easiest path to ground is through the spark plug! If replacing the plugs use only NGK brand.

 

This will solve most running problems, if not, we'll look deeper into the carburetor.


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#6 banzai510(hainz)

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Posted 09 September 2016 - 05:38 AM

put a timming light on there also.

Most is a simple adjustment

 

if stock carb that 45yrs old maybe a issue also.

 

convert to a Pertronix ignition


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#7 Stoffregen Motorsports

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Posted 09 September 2016 - 08:55 AM

Has the truck just come out of a long slumber? Or do you use it regularly?

 

Could be a fouled distributor cap or bad wires. Does it backfire?



#8 Droski

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Posted 19 October 2016 - 12:56 PM

im starting to lean towards the carb on this issue

fuel is getting delivered and the ignition system looks to be okay



#9 datzenmike

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Posted 19 October 2016 - 03:29 PM

Ignition is easy... got spark or not. Assume you saw sparks?

 

OK then, this is all good information and points toward the cause. Fuel to the carburetor and spark to the plugs. It would appear that the carb is not properly mixing the fuel with the air.

 

Could be  the primary jet is part plugged, sediment or water.


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#10 banzai510(hainz)

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Posted 20 October 2016 - 06:11 AM

ck for distributor bushing wear and condenser if still have points.

I would cut out above idle to find my condenser was bad, but now have a Pertronix ignition


Throw on some Weber sidedrafts, Rising Sun hood.... call it good

#11 racerx

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Posted 20 October 2016 - 09:00 AM

Could be running too lean. Have you tried adjusting your idle jet?


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#12 zed1

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Posted 20 October 2016 - 10:18 AM

The Nikki is a good carb for the anemic J13 engine. If you buy a used carb from someone you do not know for certain it is in good condition.

Send your Nikki to royze.com for a rebuild.

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#13 datzenmike

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Posted 20 October 2016 - 11:37 AM

Idle mixture adjusts.... idle. Anything above idle is the slow speed circuit and the primary.


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#14 Droski

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Posted 14 December 2016 - 12:41 PM

Okay I think I figured out why it's hesitating when I'm giving it some throttle. Gas is leaking IMAG0541_zpsxxuquiwd.jpg

#15 Droski

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Posted 14 December 2016 - 12:42 PM

Time for a rebuild?

#16 Droski

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Posted 14 December 2016 - 12:56 PM

Time for a rebuild?

#17 Draker

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Posted 14 December 2016 - 02:16 PM

Most likely.. yeah.


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#18 wayno

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Posted 14 December 2016 - 02:18 PM

Time for a Weber.


 

 


#19 Droski

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Posted 14 December 2016 - 03:20 PM

The Weber haha I know. This Nikki was working great so I'll just stick with it. I'm still running the 4 speed. It's cruiser.

#20 wayno

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Posted 14 December 2016 - 04:33 PM

Does the Nikki have 3 or 4 screws holding the front float glass on?

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