2150a troubles

[robert.humm]

recently rebuilt my carburetor, was having problems with backfiring through the carb when accelerating.. still doing it after rebuild. but not nearly as bad.. kind of sparatic really. what could this be? any suggestions?

 

[Hotrodlincoln]

Sounds like a timing problem but anything can happen with these old carbs.
A typical problem with these is the power valve diaphragm will rupture and spew fuel into the intake through the vacuum hose. This is generally caused by... backfires, which it then causes more of once it ruptures.

The best place to start is with a rebuild (which you've done) and be sure to remove and clean the jets in the bottom of the fuel bowl, and blow out the air bleeds with compressed air. Clogged air bleeds will create a rich mixture which will lead to... you guessed it, backfires.

 

[robert.humm]

mmk. i haven't gotten it all adjusted right yet, im going to do some tomorrow. but i guess a good place to start is to make sure im not running too rich, & check the power valve? The timing was set right on before i rebuilt the carb.. should i adjust it? it's set at the "factory recommended" 10..

 

[kimcrwbr1]

if you have raw fuel in the vacuum line on the power valve either the valve or gasket is bad. that is the small vacuum line under the front of the carb to the vacuum port on the manifold just below it. turn both idle adjust needles out 1 1/2 turns from lightly seated position then warm the engine all the way up. Then unplug the throttle solenoid the motor that controls idle speed then turn the idle needles in then out one at a time to reach the highest lean rpm do that a couple of times to each then plug the idle motor back in. turn the engine off and check that both needles in no more than 1/2 turn different between the two count the turns in then back out. unplug the idle speed motor before you start it the plunger should be out this is the curb idle start it and adjust the position of the motor for the correct high idle then plug it back in it should drop to normal idle speed about 700 rpm. If you unplugged the spout wire and timed it with the pointer not the circle you should be good on the timing GL once you get that all good then you can adjust the choke if you did not mess with it it should be close

 

[alwaysFlOoReD]

I was under the impression that a lean mixture causes backfires.
Richard

 

[kimcrwbr1]

Just make sure all you wiring is plugged in you clould also disconnect the battery for 15 minutes then drive it for another 10 to get it good and hot

 

[robert.humm]

the carb also doesn't have a throttle kicker assembly/throttle position solenoid (or whatever goes there).. is this an issue?

 

[kimcrwbr1]

does it have the duraspark conversion. with mine even after buying all the emmission crap and it never would rum good for any amount of time till i had to pop the hood to tweak it. if your running with the computer to advance the timing you might get lucky with just adjusting the carb as I said above you wont have the curb idle tho as the computer controls the idle. do you have the screw on the carb base to set the idle speed

 

[kimcrwbr1]

do you have a pic of what you do have if you want it to run good you might have to duraspark it as the TFI dont work too well unless everything else is hooked up and working. It costs about $130 for the ignition system new and you just need a harness from the bone yard maybe $10

 

[robert.humm]

no it has not been coverted. i am in the process of collecting all the necessary parts for the conversion though. here are a few pics of what i have.. whoever had this before me changed & removed some things..

<a href="http://s99.photobucket.com/albums/l288/bigcreekcattle/?action=view&current=0313001207.jpg" target="_blank"><img src="http://i99.photobucket.com/albums/l288/bigcreekcattle/0313001207.jpg" border="0" alt="Photobucket"></a>
<a href="http://s99.photobucket.com/albums/l288/bigcreekcattle/?action=view&current=0313001207a.jpg" target="_blank"><img src="http://i99.photobucket.com/albums/l288/bigcreekcattle/0313001207a.jpg" border="0" alt="Photobucket"></a>
<a href="http://s99.photobucket.com/albums/l288/bigcreekcattle/?action=view&current=0313001208.jpg" target="_blank"><img src="http://i99.photobucket.com/albums/l288/bigcreekcattle/0313001208.jpg" border="0" alt="Photobucket"></a>
<a href="http://s99.photobucket.com/albums/l288/bigcreekcattle/?action=view&current=0313001208a.jpg" target="_blank"><img src="http://i99.photobucket.com/albums/l288/bigcreekcattle/0313001208a.jpg" border="0" alt="Photobucket"></a>

 

[robert.humm]

sorry.. guess html doesnt work here lol. here are the urls..
http://i99.photobucket.com/albums/l288/bigcreekcattle/0313001208a.jpg
http://i99.photobucket.com/albums/l288/bigcreekcattle/0313001208.jpg
http://i99.photobucket.com/albums/l288/bigcreekcattle/0313001207a.jpg
http://i99.photobucket.com/albums/l288/bigcreekcattle/0313001207.jpg

 

[kimcrwbr1]

I could not open the links but in the tech library under duraspark conversion there is a list of part numbers I got my harness from the bone yard out of a 84 fanger 4cyl you could possibly the harness and the module used but recommend a new/rebuilt distributor. the tech library tells how to wire it I am using the stock coil and works great

 

[kimcrwbr1]

You can use that carb all you will need to do is put a metering block on the back of it where the feedback solenoid is. the round thing out the back with the two wire connector

 

[kimcrwbr1]

does the vacuum line from the power valve to the spacer fit snug it looks a little large to me like a fuel line insted of a vacuum line

 

[kimcrwbr1]

Also does the choke open all the way when warm you could wire it to the alternator or the ignition i would try the alternator first use the connector that don`t have power to it when the key is on but has power when the engine is running