So I have had my 87 Samurai for about a month now. Have run 3 tanks of gas through it. 1st tank 20mpg, 2nd 13mpg, 3rd 11mpg. I have put new fuel filter on, air filter, plugs, wires, distributor cap, I have also run Lucas Oil carb cleaner. So now I am stumped. As in another post I asked about replacing the gas tank as I found some rust in the old filter, most people said just to stay with it and keep and eye on the fuel filter.

The arrow points to some sort of leak. So I am now thinking I need to do a Carb rebuild kit. Any suggestions would be great. I know my MPG should not be this bad and I need to fix it. Thanks in advance!

You would have to be leaking A LOT of gas to get just 11 MPG ("normal" MPG is in the 25-low 30s range).
Check/adjust timing?
Check/adjust valves?
Cylinder compression check?
How many miles on the engine?
Pulled the plugs to see what color they are (light tan is ok, dark brown or black is not good).
Stock samurai (lifted, gears, tires, etc.)?
How do you drive, where do you drive?  If you "drive it like you stole it" and/or drive in a lot of hills, then you could get really crappy MPG.
A partially clogged fuel filter (from rust) should not cause it to get that bad of MPG....it will more likey just make it run poorly from fuel starvation.

I am running everything stock, I have 235/75 tires. But no lift. I think it may have an aftermarket fuel pump but not sure. And I drive just around town for the most part, no big hills, but I am at 4500 feet elevation. I have not checked my timing that is my next step.

as per above ( compression. timing. etc, all good)
then. (it is very sick and you MPg is off the charts)   way off.  (Chevy Blazer v8 gas hog off charts)
rebuild carb.

get a new carb that is rebuilt.

boil it , kit it.

could be stuck open , float valve ,leaking like a dog


cheers.

yoy loss mpg ! but did you loose hp ? 

Wow thats really bad. do you smell gas all the time?

I have a carbed 1.3 88 samurai with 5 inch lift and 31 mickeys and i get about 30 to 35 mpg all city and trail driving. she dont see the highway

I also drive like a grandpa.

yoy loss mpg ! but did you loose hp ? 

Very important question indeed.
So did you got power loss or just MPG suffered?

As far as HP loss, not that I can tell. But like I said I have only had it for a month. But it doesn't feel like it's dogin. I mean except for the fact that it is only 64 HP. I have not noticed any decrease in power between tanks. And I do not smell gas, and it doesn't leave any spots on the ground when it is parked. I am wondering if the tank has a small leak and is leaking into the gas tank stock skid plate and evaporating. But still seems like I would be able to smell it. But if the skid plate is catching it that would explain why I do not see anything on the ground after it is parked.

can you pressurize the tank? not sure if it is something that will work or not, but it would help show a fuel leak i think(?)

I guess first thing first, check the timing, and then check for leaks. A bit off topic but will a venturi tube help with MPG at all, or only the flat spots in power?

big loss! Here would be some checks:
assuming you have set timing( a couple of degrees advance will be good at elevation if it doesn't ping.
check float level in sight glass on front of carb, should be equal with dot in center of glass. Use a flash lightto View and rock the vehicle slightly to identify. A level that is more than 10 0/0 above needs attention.
check the choke pull off. With a fully cold vehicle remove the air cleaner, have an assistant press the gas pedal fully open and hold it there for 3 seconds. The choke plate should fully close and blocks air flow through the primary venturi. Have a assistant start the vehicle while you observe the choke. As the vehicle starts the choke pulloff should open the choke betwen 1/8 to 3/8 inch.
if those 2 look good then you will need a vacuum pump to check the diaphragms on the distributor. Choke pull off, and egr valves. All three should hold 5 inch of vacuum indefently.
do you have a dvom? (volt meter) monitor the voltage between the o2 sensor and ground ( negative batt post)
check the voltage with engine running |removethispart|@ 1500, 2500, and 3500 no load. The voltage should be between 0 and 1 volt dc. Over . 5 volts is rich, under .5 is lean. At 2500 you should see a switching between .3 and .7 volts with 10 switch's in 10 seconds
email me with your results or any questions|removethispart|@ robsandfreak|removethispart|@yahoo.com