Float adjustment and fuel pump checkout

After spending a year finishing up a CMC that was partially built I was excited to have it pretty much done and ready to drive. It has a 2110 that was purchased new around 94 and was started once by the previous owner and a couple of times for a few seconds after I completed the wiring. Well now that I tried to let it run for a while it runs like crap. Electrically it checks out and firing order is good. Carbs had some scum in them but cleaned up. Jets are all clear. There was very little gas in the bowls.

Does anyone have the specs for adjusting the floats for Dellorto 40's? Also how can I be sure the fuel pump is good? Turn it over for some period and see how much fuel is pumped in a bowl?

i just finished installing a new fuel pump an hour ago. The old pump worked when I tested it in mason jar, but it would not pump or build pressure. I replaced it and that did the trick.

To test you old pump, disconnect it from the flow end, before the filter and have the gas pumped into a jar/gas can. It should fill a quart mason jar in under a min... if it doesn't then it is bad. Place your finger over the flow end to see if it builds up pressure too.

Or so this is just what I figured out on mine.

This relates to Weber carbs, but may well be of use:

http://waitresses.servebeer.com:81/vwpage/

Browse to the Weber IDF section

That's an interesting link, Jon. Thanks for sharing it.

Ron; get the Dellorto Superformance book by CB Performance (only $9.95 from them). It's worth a lot more and it's great reading; it'll definitely help you dial them up.

Thanks everyone. This helps a lot!

I cleaned out the carbs and set the floats. I also checked the flow of the fuel pump. 24 oz. in 1 minute. Slightly under the 32 oz. suggested but don't know how bad that is. Started it up and it ran great for about 15 seconds and then went right back to running on 2 cylinders. The exhaust for the 2 front cylinders was cool.

I have an electric fuel pump I think I'll wire in temporarily and see if it helps.

Might want to check your plug wires with a test light. (Could be your plugs, too. Simple stuff is usually the last thing I check, after much gnashing of teeth and flailing of fists.)

May be ralated or may not be; I let my Triumph Bonneville sit for three years in the back of may garage in San Diego and fired it up for the first time with similar results. It turned out that the squeeze-suck-bang-blow cycle was in the valve-closed position on one cylinder, and I had a fine layer of rust on the walls and piston head of the other.

Ron,

May also want to check your distributor cap and rotor for cracks. Also see if the distributor shaft is sloppy. A clamp on timing light to check each wire while running should give an indication as Cory mentioned.

I've heard of cams broken in the middle keeping cylinders 1 and 3 from running, but it's rare.

Bob

Maybe pull the valve covers and check valve clearances to make sure all are opening and closing. You can get an idea by just wiggling rockers while someone turns the engine over by hand (just make sure the key is off).

Jjr had a similar problem but with cylinder #1; it turned out to be a defective spark plug; he swapped them all and the car works great now.

Cory D. told me that you might want to check if your car was hand-laid or chop gun blown!

Huhhh????....

I could be mistaken, but I think he's mocking me, Ricardo. I think they do that out there in Southern California every year, right as the leaves change in places where palm trees don't grow.
I'm pretty fer sher it's like a festival there in San Die-bern-afrisco-Angeles, intended to be televised and broadcast to places like Buffalo, where there's already 10 feet of snow on the ground and not a Speedster in sight.
You see, it's a pretty common occurance there in La Cucamunga that a chopper-gun laid body will polarize the whirlajig framazan in such a way as to negatively influence the 1-3-2-4 firing order of almost any Type IV engine. And boy, oh boy.
You just don't want that to happen. When it does, you've gotta take a four-inch body grinder and start having at those pistons, increasing the blow-by to the point that hot exhaust is allowed to escape, melting the chopper-gun body parts into something smoother, resembling the hand-laid glass of Jimbo's spectacular ride.
That's why he gets hassled by the cops so much. His sh** is smooth ...
Again, I might be off the mark.

Uh, sorry, Ron. Humor, you know. I still say it's either no spark or rust.

I apologize for this hi-jack!

Hey Cory -

Nothing gets by YOU (Hand-laid vs. Chop-gun fiberglass thread)! I knew if anybody got my weak attempt at humor, it would be you!

BTW - Hope you're keeping warm in DC, news reports look COLD!

Hey Ron -

I'm sure once you go through the usual process of elimination, it will be something as simple as any one of the previous suggestions - including maybe faulty coil or condensor! Good Luck with your troubleshooting!

Peace - Out!

Thanks everyone. The going at the pistons with a grinder was a joke?! No wonder it spins really easy now!

Before I went after the fuel I did a compression check, 100 psi. Would have thought this would be better on a "new" motor. Not great but should run. Put an ohm meter on the plug wires. Also changed the condensor (got bit by that on a Pinto). Swapped the plugs to the other cylinders and the no fire stayed with the cylinder and not the plugs. The rotor looked fine. I'll double check the cap but remember this is a pretty much 0 time motor with all new 13 year old stuff.

Going to try the electric fuel pump today. I guess I should pull the valve covers and double check also.

If it was the coil would the dead cylinders always be the same or would it sometimes fire them?

From everything you've said, it's not electrical, it's your carb's.

Start by removing the idle jets and using a stripped down twist tie, clean the jets from the small end. Blow out the carb. passages using Brake CLean and compressed air then re-install the jets and give it a go.

Check your fuel filter and make sure it's clean, if it has Goo from sitting, it will cause problems.

The best bet is to install 3 filters, one before the electric fuel pump and one between the "T" and each carb.

Thanks Larry. I just got done starting it again still on the mechanical pump. It started and still miss fired. Big surprise! Felt the pipes and the rears were hotter but don't know if some of that could be the heat exchangers absorbing some of the heat.

As I went back to the engine to feel the pipes I heard a gurgling. Gas was pouring down the throats of the carbs. I'm guessing now that the float level is too high. I really only adjusted one side when I tore them down to clean and it was very close. I set them to what I think is the correct height (10-11mm) with the floats hanging. The problem is that all the info I have found talks about a ball in the float seat area. Mine has a small spring plunger in the needle. I set the floats making sure to not compress the plunger. When I blow in the fuel inlet and raise the float it seems that it's very high before I can't blow through the seat.

I'm thinking if I have gas pouring down the throats that I'm getting enough fuel.

What am I doing wrong?!

If you think it's the needle and seat, remove them and make sure they aren't gunked up. Also, make sure that the needle and seat move with the float. Make sure fuel pressure is between 3 and 5 psi.

Find your fuel mixture screws, (Usually at the base of each barrel and surrounded by a small spring. Seat them gently, then turn them out 2 full turns) Later, you'll have to adjust them by turning them in until the car falters then turn them out ""slowly"" until the RPM's reach them maximum)

Larry,

I think you've hit on the cause! Sure sounds like it!

Larry, When I cleaned the carbs I ran a Q-tip soaked with carb cleaner in the needle seat to make sure it was clean. Also soaked the needles. They seem to be moving free but I'll double check.

Good luck and if you need more information, e-mail me at ljowdy at aol.com

100 lbs per hole is barely minimal....but not the entire problem you are dealing with I'll go along with carbs issues
~Alan

Regarding the compression test.

Start the engine and let it run for about 5 minutes. Remove all 4 plugs. Prop open the throttle and leave it open. Take a reading on all 4 cylinders allowing the starter to turn the engine for 6 to 7 seconds per cylinder. (try for an equal time per cylinder) then record each cylinders psi.

I you're battery is good. Squirt some 30 weight oil in the cylinders and repeat the test. If the psi jumps substantially, it usually means that your rings are worn.

My compression test was done with a cold engine. It runs bad enough that I don't want to let it run that long. I reset the floats, only the wide open setting. It was obviously too far, they hit the bottom of the bowls. I have sent for the correct book for the carbs that I have. The gas gurgling problem stopped.

Engine runs good for about 10 seconds and then starts missing. Seems to now be only #3. Pipes are hot for the other 3. I'm pulling the valve cover tonight to see if I can find something wrong.

Removed the valve covers and there was no clearance in the rockers. Adjusted and it runs much better but still not perfect. It now idles but still stumbles alittle. #3 pipe is still cooler than the rest. Swapped the plug wire and plug with #4 and the cooler pipe stayed with #3.

I guess the next move is to do a better job of cleaning the carb.

Ron..maybe the one bowl goes empty due to improper float adjustment.
~Alan
"Engine runs good for about 10 seconds and then starts missing"

Alan, When I pulled the top off the carb on that side after doing what I think is the correct adjustment of the floats it had plenty of fuel in it. I did notice when I cleaned the carbs that the 3-4 side had the idle jets turned out 3 turns while the 1-2 side was turned out 2. I set them both at 2. I guess since it will idle know I should go through the adjustment procedure.

I didn't notice the change in running after I adjusted the valves like I did before.

Thanks

Rather than Idle Jet screw, did you mean to say the idle adjustment screw or the fuel/air adjustment screw?

Both carb's need to be adjusted as does the linkage before you're going to get any significant readings. If you have an air balance tool, use it to make sure that both carb's are drawing the same amount of air. Adjust the fuel/air screw so each carb is delivering its maximum RPM's. Make sure that the linkage is opening the carb's at the same rate. This requires that you repeat the air balance adjustment each time you make a linkage adjustment.

Thanks Larry, I meant the fuel/air screws.

Problem solved! I played with the idle mixture screws more and noticed that I could completely close the front mixture screws on both sides and the idle didn't change. I also received the CB Performance Dellortto tech book and the float settings in the book were higher (closer to the top of the carb) than anything else I had found (5-6mm and 10-12mm vs. the 10-12mm and 30-32mm that I had found). They were set at 10mm and 20mm from the factory. I had raised the 30mm back to 20mm because the float hit the bottom of the bowl.

I pulled the carbs apart again and concentrated on cleaning the front idle circuits and really blew them out. Reset the floats and it runs great! Now I think I have to readjust the valves. It's pretty noisey.