Tuesday, August 30, 2011

Rebuilding a Solex H 30/31 carb for the baja Part 1

Well, tonight I finally finished rebuilding the carb for the baja I started a week or so ago. I had to fix a faucet and paint some outdoor lights and then rebuild a carb on a lawn mower between tearing it apart and finally getting it put back together. It turned out really nice and hopefully it will run as well. I decided to do this in 2 parts because I took so many pictures so hopefully it will help someone else in rebuilding theirs. Here are the instructions in pictures.

When rebuilding a carburetor I HIGHLY recommend taking LOTS and LOTS of pictures. I always take lots of pictures anyways so I can add them to this blog but it has saved my butt more than once when I go to put it back together. I often go back and look at my pictures to see how it goes back together. My hats off to those mechanics back in the day before digital cameras and cameras on cell phones. They had to remember and put things back together without the aid of technology. These pictures show how crusty the carb was. It sat for about a year and a half so the fuel was pretty bad in it.

 I like to take shots from all sides. It helps!
 The electric choke is on the upper side of this picture.
 I like to have a place set out to put all the parts I take off. I keep all the parts I remove even if they have new ones in the rebuild kit until the carb is back together and running just in case I need to reuse something.
I took the top of the bowl off the carb here and you can see how grungy it is. The yellow stuff from the bottom is varnish from old gas. This carb looked better inside than the one I rebuilt on Ed. Then again Ed sat for 11 years before I picked it up.
 There shouldn't be any green goo on this part. Whenever you rebuild a carb you really need to let it soak for at least a day in some really good carb cleaner. It's the only way you will get all the crap out of the little passages and orifices. A lot of times people just buy the carb cleaner in a pressurized can and spray the carb down a little bit and think that's gonna do it. I promise you, it won't and you will be disappointed in the results. When rebuilding a carb, clean, clean, and more clean is the name of the game.
 On this particular carb there are 2 jets right next to each other. Remember to look at them and write down on a piece of paper where each on goes. I took a picture so I would remember. The jets are marked with a size number on them.
 This is the stuff you need to soak your carb in. It comes with a little basket for dipping. This stuff is very potent and you must wear gloves when using it. This stuff is very nasty stuff but works great. It is pretty expensive but I bought this can 12 years ago and I am still using it. I decided I am at a point now that I need to replace it but I have done literally 2 1/2 or 3 dozen carbs in this 1 gallon bucket. I definitely got my moneys worth out of it. Next time I am going to get a 5 gallon bucket of the stuff so I can do carbs that are bigger than a bugs.
 This is also a must when rebuilding a carb. You have to have compressed air and a nice rubber tip on a blow nozzle. That is the only thing you want to use to clean out all the passages. Never use wire or drill bits to clean them out. Just use compressed air and some carb cleaner in a can after you have soaked it for a day or 2. If it still looks crusty, then soak it again. Time is your friend on this part. Remember, Clean, Clean ,Clean.
I actually had to soak this carb 3 times to get it all the way clean. After soaking, I use a solvent tank and wash off the carb cleaner and then use compressed air and solvent clean or carb cleaner in a can to do a final rinse and cleaning. Here are all the parts cleaned and ready for assembly. I like to lay everything out so I can see it easily and then I notice quickly if I have forgotten to put something back in.
 Here is the rebuild kit. It's not much t look at and you will find that the carb kit you get will actually rebuild several different carb so you will have extra parts that don't pertain to your particular carb. This kit I got had a ton of extra parts because they didn't have the kit I needed so I was given all the spare parts the shop had and was guaranteed I would have all the parts I needed for my carb. It turned out to be right and I actually have enough parts left over to rebuild at least 1 more carb. I scored on this one.
 Again, I like to layout all the parts from the rebuild kit so I can see what I have. Be sure to keep the instructions from the kit. They will give you the particulars on how to initially set up your carb so your engine will start. You need your engine to start before you can fine tune it! I think I almost have 2 of everything here. 
 In this part I am only going to rebuild the upper part of the carb. Part 2 will have the rest. Here I am installing the choke plate. The screws were crimped on the back side and I find that putting loctite on the screws is better than trying to recrimp them. I haven't lost a screw down an intake yet. (Knock on wood!)
 I am installing the choke diaphragm here. It's kind of like a jigsaw puzzle with this to get it to work out and function correctly. If you don't have it right it won't work so when it works, you got it.
 As the choke moves it will push the diaphragm. Remember to install the spring before you install the diaphragm cover.
 There is a plastic piece that goes in next. In this picture it is upside down. Just flip it and install.
 Here it is installed. Make sure the rod sticks through the slot. It's impossible to screw up.
 If you own a bug in Utah at least, You will end up adjusting your choke a couple times a year. To set it up initially, I line up the marks on the housing and the top of the carb in the middle of the marks. You will end up tweaking it in the winter and then again in the summer.
 Time to flip the top over and install the needle and seat valve. Make sure you follow the instructions in the rebuild kit so you get the right washer in. There are different thicknesses for each carb. It just screws into the bottom of the top of the carb.
 That pretty much takes care of the top part of the carb. Not much to it. Here is whats coming next. We will tackle the bottom of the carb and put it all together in the next posting. Stay tuned!

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