It runs... sort of!!

[Bill Tubbs]

This morning was the moment of truth. I rechecked all the connections on the carb and manifold, reconnected the battery, and hit the ignition.

Within about 3 turns, the engine fired up and ran smoothly for about 30 seconds... then gradually died.

I couldn't get it restarted although it was firing intermittently. I checked under the hood and discovered a little gasoline dripping on the exhaust manifold, telling me that there's a loose connection on the carb somewhere, or the carb has a dried out gasket somewhere and I need to rebuild it (dang). Since this carburetor has been sitting idle in a box for several years, I'm assuming the latter. Does this sound right?

I'm going to remove it this weekend or during the week and see if it's obvious. Is it difficult to rebuild a CD-150? A couple of LBC specialists I've called in the recent past indicated they charge at least a couple hundred to do this. I'm willing to give it a try for that amount of money.

What's the consensus??

Bill

 

[aerog]

Just going out on a big long limb here, but it could also be something blocked up causing the fuel to run out. Just wondering if there could be dirt it in somewhere.

There's an article about leaking SUs at https://www.mgcars.org.uk/mgoc/emg/needles.htm - maybe the idea is the same with the Stromberg.

 

[Bill Tubbs]

Well, so far it looks like the ol' "Well, DUH..." hit me. I found one of the nuts holding the carb on was loose (the one in the back). I guess my impatience with not being able to get a wrench back there took its toll. When I find a tool that will let me actually tighten the dang thing I'll just put it back on and try again. Hopefully that's all it was... I can imagine that fuel leaking from there just MIGHT be a problem...

 

[aerog]

Yes - fuel leaking in the wrong place can be, uh, interesting

 

[William]

My '76 had a Stromberg on it, and it developed a fuel drip from the brass plug in the bottom of the carb. The rubber washer was replaced, and a little blue gasket sealant smeared around, did the trick. Oh, eventually I got a rebuild kit from Victoria British (Moss probably sells these too) and rebuilt it myself. Not too hard, either.
-William

 

[Bill Tubbs]

Yeah, I saw that brass/plastic plug with the O-ring on it and pulled it out just to see. I think it's okay, but aside from just not tightening the carb to the manifold the only other problem I seem to have with it is the stupid flame-trap connector to the distributor. The tubing comes up under the carb and fits into an "L"-connector which is broken. I tried to solder it back together and that didn't work. If I can't find that connector at a junkyard (excuse me, "vehicle recycler") then I'll have to play with some tubing and just fabricate the "L" somehow.

 

[Bill Tubbs]

The car was running okay with the Weber, so I know the engine is okay. The engine appears to be getting fuel...but....

I could not get it to start up again so just left it for a day or so. On a whim, I went back and started it up again. Same thing... runs and then after 20 seconds just quits and won't restart. I've tried this pause deal several times now and it fires up each time.

I'm looking for the obvious... either getting too much gas and flooding (but I don't really smell extra fuel), or the smog crap is starving it for air.

What are some obvious places to start to trouble shoot this? Just remove all the air impediments (cleaner, et al) and see what happens?

Is there a good 'engine starting FAQ' that's already set up somewhere? The thing sounds pretty neat while it's actually running... got a new exhaust system (stock) on it.

Bill Tubbs
https://tubbs.cc/mg

 

[Matt]

Bill;
I don't have much experience but I did manage to get my MG from not running for twenty years to running semi-reliably. Your right it may be a fuel insufficiency problem. Have you disconnected the fuel line that leads to the carb? In doing this and turning the ignition to where the fuel pump starts to work you can see whether or not you are getting an appropriate stream of fuel.
Another thing that you might want to try before you rebuild the carb completely is investigate the distributor(gap and timing). This can disguise itself as a carb problem.
Good luck,
Matt
God Bless Guiness

 

[doug noll]

Bill
Another possibility to explain your symptoms is
maybe a needle and seat not closing properly,and
making the fuel level too high. This would allow
a cold engine to start but then die out as it
starts to warm up. Or maybe a float level that's
just plain too high? Or how about a float that is
holed and is full of fuel, allowing fuel through
the needle valve at all times. Good luck.
Cheers
Doug Noll

 

[William]

What sort of shape is the rubber diaphragm thingie in the Stromberg? I seem to recall tearing mine when I was trying to tune the thing (with that weird allen key tool), which caused all kinds of problems.
-William

 

[Bill Tubbs]

After getting all these wonderful suggestions, my next steps are to check out each individual component of the smog system first and leave the carb as the last part of the chain. I'd hate to mess with the carb if the problem is exacerbated by another element. I will say that while the car is running (at higher than normal RPM) it's really sounding strong. Revving it up shows quick response with no stumbling. It's only when I shut it down that it decides it's finished for the time being. More as I work with it. Thank a million, guys!!

Bill