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I think this is a photo of a CTO switch. Can you tell me how it works?

There was no stuck needle this morning as I tried a cold start. Ample fuel available as I looked into the carb as I pumped the linkage. The first attempt produced a sputter, this has never happened before. I decided to pump the gas pedal then apply the manual choke as I turned it over and it started! This hasn't happened so quickly since installing the new carb. While the engine warmed up, I backed the Jeeps rear wheels off of the shop floor placed a set of vehicle ramps in front of the front wheels and drove up on the ramps. This would simulate the incline that would cause the vehicle to flood and stall. In just a matter of seconds the motor chugged and smoked and stalled. I called the good folks at Weber and spoke to a knowledgeable fellow about the flooding issue I spoke of in my last post. He gave me some measurements to check and when I compared the distance from the float to carb housing I indeed needed to make adjustments. After the adjustments I parked back on the ramps and tested the new float level and there was no stalling this time. A trip to the back country for a test drive and once again I'm happy with the motor performance.

I should add that I have a fuel pressure gauge installed inline just before the carb and the pressure is set to the recommended 3.5 psi.

Moses I'm having some issues with my new carburetor. This past week I had the opportunity to guide hunters on a safari style hunt and ran the Jeep through our back country, and to be honest I was a little embarrassed at times, I plan on giving the guys at Weber a call but of course I'm interested in your opinion first. To begin with the engine will just not start up when cold. I purchased a manual choke and it is functioning properly as far as I can tell. It seems that not matter what technique I use or how long I crank the engine will not start, typically I just walk away for a period of 20 minutes to an hour then when I try to start again it will start with or without enrichment. The rest of the day the engine starts within a few seconds regardless of how long the engine ran previously. The Jeep idles and accelerates fine,with no chugging or missing at any time until I climb a hill, it doesn't matter how long the climb is the engine will flood and die then of course I have starting issues. This is a new Weber carb that came completely built. I adjusted the idle and have adjusted the fuel:air mixture 1/4 turn lean. Any ideas?

I re routed the fuel pressure regulator and discovered that it had a broken spring causing it to not regulate. So I was sending over pressurized fuel to a carb that requires 3.5 lbs. Later with repairs made and a few adjustments the little engine ran better than I can remember. The Weber carb is easily adjusted, cleans up the engine compartment, and most important to me stopped my engine surge issue. Moses you mentioned that I would be able to use my EGR and CTO in an earlier post? My fuel regulator issue is probably not resolved as I will need to make sure the pressure is 3.5 lbs. I don't have a fuel pressure gauge but I do have questions... It seems most gauges measure high pressure systems these days and are sold in ranges of 1 to 100 psi. I was wondering if you could recommend a set up that I might only use this one time? I ask because I use your spark plug leak down tester set up.

The Weber carburetor kit came in and I had a fun time installing it on my 4.2 engine. I just knew that once the install was complete the engine would start and run better and I could make minor adjustments and enjoy the nice ride. Remember the main issue I had with the old carb was horrible fuel mileage and my inability to make the right adjustments. I started and drove the jeep on a cold morning from the garage to the shop allowing it to warm up, total time approximately 15 minutes. The cold start took 10 seconds. This installation requires that a fuel pressure regulator be used to regulate the pressure to around 3.5 psi. I originally installed the regulator between the fuel filter and the carb... This fuel filter has two outlets the other goes to the fuel tank return. I didn't think about this until the engine wouldn't start. I pinched off the line that goes to the fuel tank return hoping that this would force the fuel through the regulator and into the carb. It didn't. So in an effort to force the fuel into the carb I bypassed the regulator. I could smell and see fuel entering the intake manifold... I could feel vacuum as I cranked the engine over... I pulled a plug to verify that I had spark and yes I had it, but she will not start. I'm lost please advise.

I'm going to set this project aside for now, the Weber carb should be here and I can install that carb on my CJ. I do plan on following your BBD carburetor instructions when I come back to this project. After reading your chapter on rebuilding the carb in your book Jeep CJ rebuilders manual, I feel confident that I can follow your steps to a successful rebuild. I will need some instruction on how to test the emission components. I'm ok with the WOT switch and the choke pull off, a little shaky on the electric choke and the stepper motor, as well as the components associated with the air cleaner. There is also an old MJ 2.5 near my home that has peaked my interest lately, I may have to pick your brain about what to look out for when buying a non running vehicle... But that is probably another book in itself.

Compression test results. 40,000 miles on original motor Cylinder #1. 132 2. 135 3. 140 4. 145 5. 135 6. 132 Vacuum at manifold. I took this to be the place under the carb with the highest amount of vacuum. 20 inches and a steady needle.

I was able to do the timing chain slack test this morning and there was virtually no play. Thanks for telling me about that Moses you saved me some trouble. I had removed the radiator to clean it and replace the hoses which also made it easier to get my puller on the vibration damper. Upon inspection of the radiator I found some hard water deposits that i'll probably find in my engine cooling jacket as well. I will buy a new radiator is there anything else I can do to prevent further scale build up? I will get things buttoned up tomorrow and complete the compression and vacuum tests you spoke about .

Just thinking back, the dent the pulley sustained was potentially enough to contribute to the damper creep. The kids that drive our Jeeps drive like they are in a Jeep commercial. They are indestructible you know! I will do the tests tomorrow.

Moses a few days ago you asked about the engine in our 1990 Wrangler I always thought it was a 4.2 liter I6 but took the time to find the engine code stamped on the distributor side of the engine. I guess the L is for long? and it is definitely a 4.2 with a mountain of emission equipment! Most of which came on the Jeep when new. This Jeep has been used sparingly over the past few years by our college interns sometime it is all we can do around here to just keep oil in it and air in the tires. I drove it for the first time in years and it felt "tight" like you had to force it to run, for the most part it ran fine on dirt, only occasionally sputtering and lurching. When the ignition switch was shut off it can't wait to shut down like a force against the motor could finally overtake it once the key was off. I'm waiting on parts for the CJ and decided to investigate what ever was causing the Wrangler's problems. I grabbed the timing light and soon discovered that the timing at idle was very advanced... almost 90 degrees by my estimate. When I moved the distributor it would run very rough before I got close to the gauge on the timing cover. I shut the engine down and wrenched the crankshaft to where the timing mark was aligned with 0 TDC. I removed the distributor cap and noticed that the rotor was pointing at the post that leads to the #5 cylinder ( if I remember correctly), I took out the #1 spark plug and turned the motor over until I thought it was at TDC on the compression stroke, then I made a mark on the vibration damper which is about 70 degrees from the manufacture mark. See photo... and the pulley is turned opposite its normal direction. I put everything back together and started the engine back up and began the timing check using the mark I made as a reference instead if the original groove. The distributor movements were more inline with the way a normal timing adjustment would go. I didn't move the distributor very much at all before locking it down. Really I didn't change the timing much at all compared to when I started. I noticed that the damper pulley was damaged and I wondered if the key that holds the damper in place on the crank was damaged so I took it off but everything was intact. Three things come to mind. Did someone change the vibration damper with one that is not compatible with my Jeep? Would the mechanical advance, if hung advance the timing this far? Did it jump timing when the damage was done to the damper pulley. I think that pulling the timing cover is my next step. What do you think?

Thank you so much for the diagrams and advice about the fuel pressure question. I'll be ordering parts today.

Thanks for thinking of me Bubba and yes I would love to go with fuel injection but given how I use the Jeep and the amount of missing emission parts... I'm going with the Weber replacement carburetor. As for the bypass mystery it looks like a Nutter bypass was performed before I got the Jeep. The three cut wires in the photo below correspond in color and lead to the ECU. I believe the stepper motor should be where the block off plate is on this rebuilt carb. Moses a couple of questions before I order the Weber carburetor. The install guide I downloaded mentioned that the recommended fuel pressure be 3.5 psi, Do you think I will be able to attain that pressure? What is the best way to check the fuel tank liquid check valve?

A couple of photos to show what I mean by a bypassed module, sorry for the out of focus cell phone photos. In the above photo a yellow wire was spliced into the purple wire of the module. From there the yellow wire was connected to a purple wire that disappeared under the distributor cap. This part should not cost very much to replace if I knew the part number I could look it up.

The Howell system is looking better all the time. You may not recall that I live in the middle of nowhere and some of the parts options are not available here. All of my projects are hindered by this fact and it is the most difficult part of the project. The budget is undetermined at this time. Presently the engine runs and sounds fine except for the lurching/surging issue I spoke of. After a couple of hours driving your throat will become sore from breathing the fuel rich exhaust is something I would like to remedy. Photos and questions are coming...

Dang Moses! Shame on you for telling me about the Howell system, it is very attractive. I have to assess my problems first I'm sure that to repair and replace the original parts would help my Jeep very much. I found out from the previous owner that the ignition module or the engine control module I'm not really sure of the name was bypassed because a new one would cost $800. This is what made me think to ask if removing all original equipment and starting over with simple parts would be the way to go. I'm sure I'll be asking soon how to test a carburetor solenoid vac and a CTO.

Hello everyone! Well it is that time of year again when it is too cold to drive around and it is time to work on the few problems that will make the jeep run better. I think first I should say a little about the jeep. It has 63,000 miles and the engine is in very good condition. I rarely drive it over 25 mph. I don't drive it on pavement, most of its miles are along rough ranch roads, and the stock axles, transmission and transfer case serve my needs very well. I work in wildlife conservation and the jeep's primary purpose is to travel from point A to point B at a slow rate of speed so I can observe all things flora and fauna. Most of the time it is a quiet, comfortable ride. This CJ to my knowledge has always been inefficient in fuel economy. Recently I discovered that the ignition module had been bypassed and all of my attempts to balance fuel, air and a smooth running engine have not yielded good results. Fuel economy as low as 3 mpg, too fast an idle or a very annoying idle surge event that is just aggravating to say the least. My evap canister is leaking at times and not in very good shape I would like to remove it. The catalytic converter has been removed. My carburetor is an aftermarket replacement. I would like learn more about my specific problems so I could make a decision to either remove stock components and replace with a simple set up that would allow the jeep to operate in a way that suits my needs, or replace all stock parts. I honestly don't know the best course to take... So I'll need your help. Thanks!

My son is serving in the Navy, currently in Charleston SC recently he had some bad luck and I found a '91 c 1500 Chevy for him to drive. The only problem was that the truck was 1150 miles away in Texas. My wife and I had limited time to travel and bought the truck and started on a very long test drive... Honestly I took almost every tool I owned in anticipation for a break down of some type but was pleasantly surprised to travel the entire distance trouble free. The transmission was one of the most important potential problems as it had some shifting issues that I mentioned previously. I forgot to get a picture of us after spending an afternoon working on the truck and the next day it was raining, but I did get a photo of the oil pan and sediment. I really think this transmission had been serviced at least once in its life. I'm back home now and my son is enjoying the truck I'm sure you will hear from us again. Jeff

We replaced the filter and fluid yesterday and the test ride was the kind you like to take after improvements to you vehicle ...very noticeable changes resulting in a NICE ride. The debris in the pan was very small and soft and difficult for me to identify, pictures will come later as I'm away from home. Moses thank you for your detailed answers I always learn in a post from you.

We will get the fluid and filter changed tomorrow. I think the transmission will respond well. I found myself thinking about how a 1991 automatic transmission is supposed to feel like and how can I relate what I'm feeling and hearing? The tranny has some age on it and I am used to newer hi tech components that shift smoothly. Maybe you could tell me at what speed I should shift from first to second and so on. Also could you describe what a hard shift or a slipping shift is in your words so we can be on the same page when I describe what happens tomorrow. thanks

Hello Moses! I bought a truck from a relative for my son. I also purchased your book Chevrolet & GMC Light [Duty] Truck Owner's Bible that I am having sent to him, so I won't get to read it until I visit again. I should start by saying that I delivered the truck to him and will be visiting for a few more days before returning home. The truck has 171,000 miles and has been maintained fairly well aside from a slight leak in the radiator and a bad signal from the coolant temperature sensor, an oil pressure gauge that seems to read high, and a sticky brake light switch are going to be fun to repair with my son. The transmission, however, has been neglected and seems ok now but I need your advice on the best way to approach "preserving" it for a time when we can either rebuild it our selves or save up and have the work done by a professional. As I mentioned it seems ok now but occasionally seems to have a hard shift while shifting down. The trans fluid is more brown than red and I am getting ready to change it and the filter and if possible the fluid in the torque converter if you think that needs to be done. I think I was able to read the letters MD8 on the bell housing. Could this transmission be a 4L60? Also could you give us someway to test the function of the transmission so we would know how to assess any problems? Looking forward to hearing from you! Jeff

My vendor problems persisted through out the spring and early summer. In my frustration I put the project aside for a couple of months and stopped thinking about it for awhile. I chose to proceed with the Pro X piston in lieu of the fact that I could not communicate with the company and have them answer my questions about the ring expected life. I watched Moses' repair to his engine and used all of his tips along the way. Really building the top end of one of these type of bikes can be done without a lot of experience my skills can attest to that. The piston kit instructions outlined the procedure and gave specifics as to ring gap and alignment around the piston. The cylinder slipped over the piston and rings, and was bolted and torqued to the engine case then the head was secured and torqued also. Then I added oil and checked the valve clearance and buttoned up the valve cover, coolant hoses were replaced and installed and coolant added. Air box and filter inspected, the carburetor and fuel system cleaned inspected and installed. A new spark plug and ignition wires installed. Next the starter and exhaust system were replaced. The balance of parts like the counter sprocket and chain foot pegs and seat were installed. A fan placed in front of the radiator to help move air through the coils. A deep breath and a touch of the starter button brought the new engine to life. I've seen how bad things inside an engine can be worn and the engine still run so I don't know why I get so excited when after I've painstakingly rebuilt an engine and started it up for the first time why I'm amazed that it starts so easily... It is doing what I want it to do right? I followed Moses break in procedure. Really it took some restraint on my part to not be tempted to do it my way or take a short cut, but I'm certain that his experience is on my side and will ensure long engine life. I changed my break in oil at seventy five miles and replaced with conventional oil and am happy to report that after 500 miles the engine has not used oil, runs strong with a quick throttle response and gets over 50 miles to the gallon. I smile every time I get on it!

Excellent post! You detailed the procedure with examples, discussions and answered all of my questions. My Kawasaki owners manual said to vary speeds and stay under 4000 rpm for the first 1000 miles. I don't think that many people would do that. Thanks again Moses!

I have an OEM replacement piston and rings on order for my KLR engine build. Enjoyed your "test ride" with the Honda XR650R, anxious to get my KLR running now! I'm curious about your engine break in procedure. Could you comment?

I purchased an over sized piston from Pro x and had my cylinder bored to accept the new piston. I went online to see what the ring gap specs would be when I saw that the maximum amount of hours was noted as 20 hours? Really only 20 hours what did I buy? I've included a link to the instruction page, I'm referring to page one last sentence in the box. http://www.pro-x.com/media/downloads/Piston%20Kit%20Instructions.pdf