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Which is where I am! You watched the rain get pushed up here. Been raining for just about 36 hours straight and there is a flood warning for this area until noon.
 
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Yeah, the prices are kickin' all our butts. And yep, I'd say you should run the highest "octane" you can get in an LBC.

Do you have the 74 carbs Will'm, or the earlier ones? Reason I ask is the pop-off valves in the throttle plates can do this too. But I think we went thru this before.

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My car has earlier carbs. Can't remember the model number, I just remember that they're *not* the HIF4 carbs that came factory on a 74.
 
Blame Mr. Laird /ubbthreads/images/graemlins/wink.gif I deny culpability...

William, carb "number" is no matter. Good you have the earlier ones. Try tankin' up with 93. I'll bet it quits doin' the dieseling.
 
Or wait until you are really really low, then try a quarter tank. Your run-on 'could' be something else.With 93 mover $3.00/gal you might look at some other possibilities. Too high idle, carboned up combustion chamber are possibliities.

Guinn
 
This might be a stupid answer, but often those are most illusive...do you have an anti-runon valve hooked up? They came with the 74 wiring harness and was perhaps removed with the engine swap?

Bruce /ubbthreads/images/graemlins/cheers.gif
 
[ QUOTE ]
This might be a stupid answer, but often those are most illusive...do you have an anti-runon valve hooked up? They came with the 74 wiring harness and was perhaps removed with the engine swap?

Bruce /ubbthreads/images/graemlins/cheers.gif

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I don't think the '67 has the anti-run on valve. In my case it might be the gas and I will be adding 93 as soon as I can.
How does one go about clean the carbon from the combustion chamber?
 
Two-hour run down the Interstate and back. With premium fuel. /ubbthreads/images/graemlins/devilgrin.gif
 
Hopefully in the next few weeks.
Clutch slave & MC, and Brake MC still out. Pedals out. After those are cleaned & rebuilt, the list goes onto rear Brake cyls and then Calipers. That is if remaining clutch components are in good working order.
New shoes and plates & I should be good to go on the two hour run on the interstate.
(oh and of course I need to change my shifter around) /ubbthreads/images/graemlins/devilgrin.gif
 
heh. It'll pro'lly shift BACKWARDS! /ubbthreads/images/graemlins/jester.gif
 
High speed run for an hour or so will often shake loose the carbon. Especially with high octane.

Years ago we used to spray H2O into the carb while keeping the engine running at high idle. Blew a lot of gunk out. I don't know that I would try it with MY car these days, but it did work. Anyone else have an opinion (based on experience) about this?

Guinn
 
One thing I have done is to open the throttle wide just after you switch off. This will break the manifold vacuum and stop the fuel from being drawn in where it can burn due to the hot spots in the CC. It only works with carbs that don't have accelerator pumps (like SU). You might also check your mixture as you might be running a bit lean and causing more hot spots. As mentioned, a good high speed run and higher octane fuel might also help. Check the mixture before any high load work!
 
Would you check it with current fuel or with 93?

How do you determine if it is running lean or rich?
The exhaust does not smell that bad as if it were running rich.
 
Do you have a Bentley manual for the car? That is the "bible" for the MGB's and has a very good carb section explaining the process and how to determine proper jet settings. Other things like a ColorTune or two would help as well, but $$.
 
I do have a bentley book and the only other item I own for the carbs is is is... round thingy with a pipe and little red cap that elevates, you put it over the carb and you used it yesterday dummy !!!.AHHH! (thumping to skull) "think brain think" /ubbthreads/images/graemlins/hammer.gif
 
That won't get the mixture straight, just the "balance" between carbs.
 
Yeah I know. I just wanted to state the only carb tool I have an brain dead right now.
I guess color tunes are pricy?
 
That depends on what you consider to be pricy, and what the price is relative to. If you're comparing to one of those Gas Tune (green boxes), it's inexpensive. If you compare to one of those 4 gas exhaust analyzer things, it's hella cheap.... /ubbthreads/images/graemlins/smirk.gif
 
Guinn, A few years back, Well, maybe a little farther back than a few, I was heavy into restoring antique cars of the 20s and 30s era and in doing so, I used to talk to a lot of old timers for information about certian vehicles. I heard it more than once that the best way to clear an engine of carbon was to inject a fine spray of water in the carb while running the engine about 1/4 throttle. I tried it on a model A Ford and it worked! What else can I say.
Also, water has a pecular way of reacting in an engine, especally at full throttle. Injected at the proper proportion, at full throttle, it will actually increase horsepower for short bursts. The theory was used in WW2 on radial engine fighters that they might get a quick burst of speed in dog fights. If left on to long though, it would raise the internal cylinder temperature so high it would actually burn the exhaust collector manifold off of the engine. /ubbthreads/images/graemlins/cheers.gif PJ
 
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