Idle problem. Carb problems?

[BJones]

Ok here we go. I bought my TR6 a little less than a month ago and I am trying to get things ironed out. I have ZS's and a petronix EI, my engine will stall unless I leave the manual choke on a little at idle. It doesn't matter whether the engine is warmed up or not. After driving at speed, I get a little light backfiring as I let of the gas pedal and decelerate. The PO said he had the carbs rebuilt and tuned by an old Jag mechanic less than 2000 miles ago. I stopped by Motorhead today and spoke with them about the issue and they told me to bring it in, of course. Obviously not a bad idea, until I asked what they thought it might run to get things sorted out. He told me their standard carb service is $750-$1000. I about dropped dead. Does this sound normal to you all? For that kind of money I can almost upgrade my carbs to Webbers or HS6's. That is not something I currently want to consider. So I either need to find a better price to have these adjusted or learn to adjust and balance them myself. That finally brings me to my questions.

Does that price seem high to you?

Can any solid mechanic with carb experience handle this kind of work?

Is it easy enough for me to learn to do it myself? If I do it myself, where do I begin?

As always, thanks in advance.

 

[Guest]

I'd buy the tools needed and the haynes carb manual. It's not rocket science, and you'll have change from $100.

 

[Norton47]

I found out from a local gal that ownes a TR6, a shop here charged her 1500.00 to rebuild and tune carbs and an oil change.
Also check the timing first, I tweaked on my carbs and then found the timing off, then had to reset them.

 

[Andrew Mace]

[ QUOTE ]
...I stopped by Motorhead today....He told me their standard carb service is $750-$1000....Does this sound normal to you all?

[/ QUOTE ]Uh...WOW! /ubbthreads/images/graemlins/shocked.gif I'd hate to ask what their "deluxe" carb service would run!

Seems to me you could pull your carbs in about 30 minutes, box 'em up and send them to someone like Joe Curto, get them back pretty much ready to go for maybe $300-400, slap 'em on, warm up the car and make any needed final adjustments...and you're still a few hundred bucks ahead.

 

[Banjo]

$750-1000!!!!!!!!! Great googley moogley!!!! what on earth are they gonna do? gold plate 'em?
See if you can get info on a local club or something. There's gotta be someone not to far away that would be willing to take a look.
It could be as simple as adjusting the idle screws, but it probably just needs to have a good complete setup. Mixture, idle, balance, choke and the like. also, check for vacuume leaks. a hose off somewhere, or a cracked hose. The PCV system greatly effects the carbs too. make sure that's all good.
Definatly invest in the service manual, and the tool kit. If you've got some mechanical ability you should be able to make a go of it.
Best of luck.

 

[Dave Russell]

[ QUOTE ]
I have ZS's and a petronix EI, my engine will stall unless I leave the manual choke on a little at idle.


[/ QUOTE ]
Chances are pretty good that you could cure most of the problem by just screwing in the idle speed screws (throttle stop) 1/8 to 1/4 turn. Not the fast idle adjustment. All the first part of the choke travel does is increase the idle speed setting with a separate adjustment. Certainly worth a try before going to more drastic measures.

Be sure that you turn the idle speed screws, not something else. Wouldn't hurt to get some kind of shop manual that covers the ZS carbs & such so that you know exactly where the adjustments are. Haynes has a pretty good book. "Haynes Techbook, Weber Carburetor Manual", "Including Zenith Stromberg & SU Carburetors".

Jump in, get your feet wet. It's fun & you can rarely hurt anything by trying. Too much ignition advance would be one of the few pitfalls. Everyone has to start somewhere. For routine work such as this, some shops can be a monumental rip off. Some are pretty good at blowing smoke & making you feel good.
D

 

[hondo402000]

I would say that's way too high unless they are completely rebuilding the carbs. Have you check to make sure the vacuum hose to the brake booster or the booster it self is not leaking, another source of a vacuum leak. is the timimg marks on the harmonic balancer correct? I have heard it may spin on the rubber and 0 will not be 0. it sounds more like a timing issue to me if its backfiring

 

[AltaKnight]

Re: Idle problem. Carb problems?

The price is way too high.
Learn to mess about with them yourself.
Sounds like you just need to increase the idle speed screw on each carb, just try adjusting them 1/4 turn at a time.
I've spent quite a bit of time getting mine "just perfect"
The light backfiring as you let off the throttle on the over-run could be ignition timing, however mine used to do that when I had one of the carbs leaned out too far.
The best guide to judging carb mixture settings is checking the plug color after a good long run (let the engine cool down first so you don't burn yourself. You can figure each carb out individualy by the cylinders it serves.
You need an adjusting tool (get it from one of the big 3 vendors) you turn anticlockwise to lean it and clockwise to enrichen it.
If you can't get it adjusted right then you may have other problems such as incorrect float height (ask me how I know this)
I would start by checking plug color, that will give you an indication of which carb to adjust and how much.

 

[BJones]

Re: Idle problem. Carb problems?

Well I will definitely have to start playing with it. The PO gave me the ZS adjustment tool and the balancer. Just not really sure how to use them. I guess I should also try to find a copy of the Haynes manual mentioned above. Is there a perferred way to check for vacuum leaks? Spray bottle and some water?

Thanks everyone!

 

[Guest]

Re: Idle problem. Carb problems?

use carb cleaner not water

 

[Tinster]

Re: Idle problem. Carb problems?

Ouch!!! Way too high a price.

I recently had my TR69ish Stromberg twin carbs
totally rebuilt and refurbished by carb guru
Jeff Paltech in Ohio. $475 total package. I highly
recommend the investment. And Yes, my carbs came back
to me looking exactly like the carbs on Jeff's web site.
https://paltech1.com/_wsn/page5.html

tinster

 

[BJones]

Re: Idle problem. Carb problems?

[ QUOTE ]
use carb cleaner not water

[/ QUOTE ]

Duh... I guess it would be really dumb for me to get water in there. Thanks!

 

[Dave Russell]

[ QUOTE ]
After driving at speed, I get a little light backfiring as I let of the gas pedal and decelerate.

[/ QUOTE ]
Backfiring (exhaust popping) on over run is frequently caused by small air leaks in the exhaust system. At this time there is usually some unburned fuel passed through the engine & out the exhaust. There is not normally enough oxygen present to allow this fuel to ignite. Leaks in the exhaust plumbing will allow enough air to be sucked into the piping to provide a combustible mixture & some popping. This is why cars equipped with air pumps have control valves to cut off the air injection on over run.
D

 

[tomkatb]

80--90% of all carb problems are actually Distributor issues. Yours would be the description of a vacuum advance problem. I drive a 77 Spit and 63 B.

I would take the cap off and connect a piece of hose to the vacuum advance module and apply a vacuum(suck on it, tastes like ugh, a mighty vac is a good idea.) and see if the plate moves. If it does not then the module is bad or disconnected.

Never touch the carbs until you are sure the dizzy is not the issue. Repeat this phrase several times.

The price you were quoted is absurd. Our local guy would charge $400-500 to check out the dizzy, remove and rebuild the carbs. $100 in parts and $50 in machine shop time with 4-7 hours shop labor. It is all DIY stuff you could do with help and books and lots of time.

Larry