View Full Version : Spitfire My 76 Spit Stutters.... Speach impediment?

12-13-2009, 01:58 PM
I have replaced plugs & wires, checked timing, use ONLY premium fuel and checked all vacuum lines. During accelleration or just revving at a stand still, she stutters between 2000 to 2300 RPMS. Fuel mileage sucks as it goes through a little more than 1/8 tank to go 24 miles to work. She is running rich as you can smell it and LOTS of soot at the tailpipe. And the EGR valve is disconnected with the vac line pinch closed. (the way it was when I bought it)
She starts pretty easily whether cold or warm, idles kind of smooth....slight shudder while idling. And I know it isn't a V8 but the performance seems lousy. Obviously during the stutter but even when not stuttering...jsut doesn't seem to have the "oomph" that is should.

Now I have done alot of shade tree mechanics on my usual toys which were american cars but this is my first Brit so any tips would be helpful.

Thanks all!

12-13-2009, 03:37 PM
:nopity:Sounds to me like DIRTY FILTER problems somewhere.
If its blowing black its fixable
If its blowing blue it needs a ring job.
Also maybe the CARB(s)are out of adjustment.
Ken&Whitelightning just my 2 cents.

12-13-2009, 03:55 PM
sounds pretty typical of a Weber set up..

12-13-2009, 06:39 PM
Filters have been replaced... And I live on dirt roads that are nice and curvy...so ummmm Plenty of "blow out" done around here....hehe (Who says 44yr olds don't like to drift. :wink: )

This does have the single carb so I will check the damper. No smoke blowing at all...idling or getting on the throttle.... cold or warm.

What about carb adjustments? I have heard that these single OEM carbs are pretty finicky and no two set the same. Is there a "guide" on adjusting them? I have been thinking about adjust the mix to ease out of the rich condition but not too much so I don't end up causing too much heat for the engine. Any special carb tools?

12-13-2009, 06:59 PM

start there


12-13-2009, 10:25 PM
When I did my engine I overlooked the rockers, thus giving a lousy idle and the black soot.
As RG states" Stock TR rockers have a chronic problem of wear and galling on the shaft"
sure enough after pulling the complete assembly (motor has 40K, original)found that my first set of I and E was super sloppy and the next pair was wearing as well

There for I have replaced and all is perfectly well

just some thing to think about

12-13-2009, 11:09 PM
Bill - Black smoke, smelling fuel, poor mileage all strong point to her running rich.

These carbs are actually pretty simple to work on, so don't be afraid to dig in. We can provide any coaching necessary. Do you know how to check the mixture on the carb and adjust it?

12-13-2009, 11:48 PM
This is a ZS carb ?
If so, could be a float chamber needle valve not closing off when the float chamber is full of gas. The excess fuel entering the float chamber will flood the engine.
Be sure to smell the oil on your dipstick. It could well be diluted with gasoline. You'll smell it if it is.

12-14-2009, 09:59 AM
Thanks for the tips guys. I am going to leave work early today while the weather is still cooperating and check the carb out from SILENTUNICORN's link. She only has 54K original miles on it and the previous owner mentioned that he tinkered with it a bit but didn't get too far since he had other projects. Of the things he said he did was adjusting the carb how he thought it should be then admitted he never worked on a Spit before....so I am betting on the air/fuel mixture with the dual adjustments. Will probably have to reset the timing and clean the plugs again. Running this rich probably caked them pretty good.

I'll check the smell of the oil too.

And yes it is the ZS carb.

12-14-2009, 01:15 PM
Sounds definitely like you are getting way too much fuel. Check out Nelson Riedel's excellent articles on ZS carb overhaul at:


The overview section will give you a pretty good idea of how they work and Part 3 will help you with the basic adjustments. ZS carbs are not hard to work on, but they are a different beast from a Weber or Holley.

To add to Poolboy's comments, you could also have a problem with floats in the carb bowl allowing you to overflow. If this is happening (either due to floats or needle) you may also see and smell fuel seeping out on the outside of the carb, in places like the choke valve (I assume you have a manual choke), and inside the air filter where gas will run down out the throat of the carb into the filter.

As noted in a previous post, make sure you're getting good airflow into the carb and the filter or air intake isn't plugged somehow. You could also have problem with the choke not shutting off. You may also want to take the top off the carb and make sure the piston moves freely up and down in the carb body, and also that the piston is not installed backwards.

Also, make sure you have all the 'restrictor' plugs installed in the charcoal cannister hoses, or disconnect and plug them all while you're trying to diagnose the problem.

If there is not an obvious problem in the above, I would go back and do a basic re-adjustment of the mixture. You will need a carb adjusting tool to make sure you don't tear the diaphragm. Use Nelson Riedel's tutorial as a guide. If all the doesn't seem to make any difference, time to pull the carb off and check it out on the bench.

12-14-2009, 07:44 PM
I would do something soon too or stop driving it. Too much fuel can wash down the cylinder walls and cause bigger problems.

12-15-2009, 10:16 AM
Oh no....The Spit only gets driven on the real nice days. Still need to replace the top so even a warm rainy day would be miserable.

She stays parked and gets out on weekends only...at least when it isn't in the teens outside. So driving it...nope....not gonna happen for a bit. Just trying to tune her in before the good weather returns.

12-15-2009, 11:15 AM
I would do something soon too or stop driving it. Too much fuel can wash down the cylinder walls and cause bigger problems.

This is a really good point - is she is as rich as she sounds you risk damaging the engine if you drive her a fair amount without fixing the condition.

It's not about the weather, it's about your excessively-rich running condition.

Can you send along a couple of pictures of the ZS carb so we know what we're looking at here?

We want to help!

12-15-2009, 11:43 AM
She only runs as I try to fix this "rich" condition. I drove it only twice to work and the weather turned so I figured this was a good time to really tune her in. The weather does have alot to do with me running it...No top. :laugh:

But she will stay parked til I get it fixed right.

I'll get a pic tonight or tomorrow....company christmas parties and getting hay for the horses.... Sometimes I think I am lucky I remembered to wear pants each day.

12-15-2009, 12:01 PM
I imagine it's the 150 CDSE or CDSEV. The Buckeye articles, although illustrating the 175 version, could prove helpful to BB

12-15-2009, 12:40 PM
I would do something soon too or stop driving it. Too much fuel can wash down the cylinder walls and cause bigger problems.

We want to help!

Geez... with all this info and help....I should of just posted my address and said..."Bring yer tools! I got the beer and brauts!"

So ummm anyone local want a free lunch? hehe

12-15-2009, 02:31 PM
Billy Bob,

Another possibility, especially for getting folks out to your house in Elizabeth, would be joining the Rocky Mountain Triumph Club. https://www.rockymountaintr.org/
It is a Denver based club but there are a lot of members that live on the south end of Denver, Castlerock, Colorado Springs etc... Its a good group of people too. Only a handful of us on this forum live in Colorado.