float bowl adjustment

[70mford151a2]

well I seemed to have the wrong info on float adjustment I'll get back to you

[rickf]

I don't know if that means you need it or not but it is 9/32 to the gasket on the body and 3/8 drop. I am usually a little generous with the drop.



Rick

[70mford151a2]

Talk to me Rick, I quess I still don't have all the facts so it's 9/32 from the top of the float to the gasket with a 3/8 drop ? man I had it all f-ed up

would that ( it being way off ) be the reason for it running so rich even without any choke at all. I think I may be gettin close to gettin it right I know I had twice that drop that's why I try to
hire real mechanics but didn't this time I quess I should have and just watched

[rickf]

OK, With the carb off take the bowl off , don't lose the idle tube that might fall out of the bowl if you invert the bowl. Turn the carb upside down with the float pointing up. You want to measure from the free end of the float down to the gasket. Make sure the spot on the gasket you use is against the body. The measurement is from the part of the float that is closest to the body down to the body. If it is off you will have to bend the arm that attaches the float to the pivot. Do not try to do this without removing the float! You will screw up the needle if you push on it too hard. For the float drop you want to hold the carb upright and measure the same spot on the float to body. If it is not going down far enough there is a little tab on the pivot that contacts the needle holder. You can bend that with the float mounted just be careful not to put pressure on the needle. While you have the carb off blow out all of the passages with carb cleaner and air and then reassemble. This is going to sound dumb but I have seen it done, When you are hooking up the choke cable make sure the cable is pushed all the way in and the choke blade is open.


Rick

[70mford151a2]

Rick, I did what you said and it does run better also had a loose plug it runs stronger but still smells like it's running kinda rich maybe that's normal

I am going to try and time it tomorrow ( it's been 25 yrs since I even used a timming light ) I have a friend who is gonna help with that do you think timming would have anything to do with it running kinda rich
I think that would explain the little backfires thru the carb doesn't do it everytime once n awhile and it's not flame it seems like atomized fuel blowing out. I think this jeep hasn't run well in a long time
and it's a bunch of small things like valve adjustment and timming . I can't wait till I get it right anyway thanks for all your help don't know what I'd do without G838.com Dave

[rickf]

I can tell you that everything has to be right on for it to run right. The valves should have been the first adjustment since if one is tight then it will screw up everything else. Adjust the valves first then set the timing and then adjust the carb. When you adjust the idle mixture do you get any change in rpm at idle? If not then something could be clogged in the carb but you have to have the other adjustments right first.


Rick

Remember, this is a forty year old motor and a 80 year old motor design. It will never run as clean as a new car.

[70mford151a2]

thanks Rick I bouight a feeler gauge to day, I have adjusted valves before mainly on overhead cams I would assume this to be easier I will read up on it though- I'll bet this motor hasn"t been "tuned up in 20 yrs but it did sit most of those yrs I have been at least running it every month or so I don't really know how smooth it will get but we will see- since there wasn't anything wrong with the original float jet I put it back in when I did the float adj. last night and it does run better it's just not there yet. my wife from in the house said it sounded better, and there are some small holes in the section of exhaust pipe that is under the back of the body could explain the "put put" sound at the tail pipe

all in all I think I will get it eventually and I won't let it come to this on my watch
promise Thanks again....everyone

[rickf]

In the book it will tell you to adjust the valves while it is running. I have done this for many years on many cars but I now have arthritis pretty bad in my hands (and everywhere else!) And I can't hold on to the feeler gauge while it is running. I just get it up to temperature and then do each cylinder at top dead center of that cylinder. Much easier on the hands and works just as well.

Rick

[70mford151a2]

Rick, ok the valves are done and I might say it's quite a messy job I just pack towels around the sides of the head
but still had some cleaning to do there ain't nothing wrong with the oil delivery- anyway put it all together gunked it down and am taking a break
I did it running cause it was easier then trying to manualy get it to tdc each time ( I tried ) I got it to book specs
two were spot on the rest not so much it started to smooth out as I was doing it, I think timming is off though
that's next and to answer your ques about idle mixture screw yes it does slow it down if you screw in to far with it running
I'm still a little confused on that setting- the book says it should be a little screw with no spring but this one is a longer brass screw w/ a tighting spring
and knuraled edges could it be the wrong needle, the carb is the no. 13841 with a 70 and a 73 stamped on it assume 73 is a rebuild date ?

anyway any advice you have is certainly appreciated

[rickf]

That is the idle mixture screw, You have a carb that there are not a lot of around. That was the second Zenith to be used and it was replaced fairly quickly with the 16660 emissions carb which had a sealed idle mixture screw. You have me wondering when you say it was a messy job because it usually isn't. Were the oil lines in place? one from the rear of the head to the rocker shaft bolt and another closer to the front from the head to the next bolt. The rear line is a pressure line and it is supposed to have an O-ring on it down inthe head. If that O-ring is missing or damaged it will squirt oil all over.


Rick

[70mford151a2]

well the oil seemed to be comming up in tiny drops from the pushrod holes
it wasn't that much maybe 1/3 a cup sprayed up and out, just a thin layer all around
I will check the level and I'm sure I won't even notice it
it was just kinda all over and trying to keep the wrench on that moving nut was fun I used a line wrench thinking it would be easier-
and it was I could feel it smoothen out while I was doing each one so that carbs an old one huh
I wouldn't think the adjustment would be as critical as say a car I assume these are pretty easy
well timing will be the next one

** I have another one #13660A with a mfg date 4 82

[raymond]

Those older Zenith carbs are better than the newer emission type carbs. Setting the timing is easy. You can do it with a 12 volt light if you hook it up to the grounded battery. You can use an old spark plug cable with the metal insulation removed so the pick up will work or you can get an old length of metal core spark plug wire and put one end in the distributor hole and the other end down the hole at the end of the shielded spark plug. It will work well enough for timing the engine. If you use a timing light with advance, set it to zero as the indexing mark on the fly wheel is already calibrated

[70mford151a2]

ok this may my last post , why ? cause I think I'll just go insane I've got it runnin as best as it's been in 6 mos ( which isn't saying that much ) so I've done the valves set the float level new plugs gapped\ to specs it will start right up almost sounds right till you give it some gas if you do it slow no problem but faster and it pops thru the carb so I get it running warm it up good
get to operating temp sounds nice so I turn it off attach the military adapter on the plug wire attach that pick up wire to adapter plug light into grnded battery ( 12v) everythings ready to go just start it up and check the timing but not so fast now it won't start runs very rich gas blowing out of the catb even got a flame this time so I just quit for now what the hell iis going on here it ran ok for 20 min. I turn it off and now ???

I think it's still a stuck float I don't think it's as bad as it is cause of timing I mean it did start right up and ran alright for 20 min. it sounds like the problem a few of you have had with the float adj. or carb related I know I keep begging for help I just can't seem to trouble shoot this on my own I'm just trying to stay out of that straight jacket

[rickf]

Are you running this without the hose to the air cleaner on? If so put it on and try that. Have you checked for vacuum leaks? Bring it up off of idle a little with the hand throttle and then spray carb cleaner around all of the intake manifold ports. Make sure to get some under each port. If the engine speed changes when you spray a spot then you have a vacuum leak. Make sure all of your vacuum lines that come off of the intake manifold and around the back of the engine are hooked up and tight. You didn't lose that little idle mixture tube out of the bowl did you? Could also be a broken power valve spring in the carburetor. I can't describe how to check that in print, I would have to call you and I lost your number. That idle mixture screw should be about one and a half turns out from lightly seated.

Rick

[70mford151a2]

"broken power valve spring in the carburetor." what's that ? and the only reason I had the air cleaner hose off was to try and flush more air to get rid of the flooding

it's nuts I tell ya when it's cold it starts right up, but once it's warm it's really hard and it's more then just that gas thet remains in manifold when you turn it off I remember whenthis engine was running really good and this ain't it so I'm gonna let it sit and tomorrow when it's cool I'll start it and check that timing ( after I warm it up )

now this power valve spring, where is it ? and what does it do, never heard of it