Another weber jetting question/problem

I had a question on jetting my weber 32/36 (manual choke)

It ran well on the stock jets, IF the (manual) choke was choked a bit. Ran like crap with the choke open.

I just changed the main jet to 150, left the secondary alone(figured do one thing at a time). I saw on elsewhere on the forum recommendation for 155 for the secondary jet. I will change that soon.

Is there anything else to change while the carb is apart? air correctors ,etc?

The float was adjusted a hair high.

When running on the highway, on one barrel, sometimes it seems to run out of gas, then catch up eventually. I can run, say, 5 minutes at a constant throttle (say 55 mph) and suddently it slows down, pumping the pedal and/or choking the carb does nothing. Should the float needs to be adjusted more?

I should check the output of the pump (SU), although new (couple years ago anyway) as well. The pump keeps pumping VERY fast, machine gun fast, not click, click click..So not sure if my problem is with the pump or carb. But will play with the pump and check the flow.

I just wanted, at minimum, to get the carb jetted and at a good starting point.

The engines head is P+P, so not sure if the jet at 150/155 would be enough, but it has got to run better than the stock jets!

Thanks

Paul

I have my manual choke 32/36 jetted as 150 primary and 155 secondary. Runs fine, but then again, I have a stock motor. Your float is super important.. mine was off just a bit and it ran like garbage... I set the float to exactly the recommendations (even used a metric digital calipers), and then it ran great.

Did you get a rebuild kit? if not GO HERE.. best price and fast shipping. Worth it for all the gaskets, diaphragm and needle valve.

If you need the float diagram GO HERE ... Mine was the DGV plastic floats.

My original pump does not act like your explaining with my Weber set-up.. so might be that is your problem.

Not sure if that helps at all, but hope it does.

John

what is the setting for the float?

Now it is set a hair higher than the manual recommends. Not sure if it should be set higher

I want to get to a known good state for the carb so I can troubleshoot if it is the pump, or possibly a leak in the tube in the tank (72), as is not uncommon.

Check pump output volume,,,fast clicking (SU ) ,,,youre sucking air or pump intake partial blockage..

pulled the hose off the carb - getting very little flow. So I know there is an issue at the pump or the tank pickup pipe.

Will have to investigate that this week... talk about coincedence.. playing with the carb's jets and having a pump/tank problem at the same time! Oh well..

But still up in the air if there is anything else recommended to change other than the main and secondary jets..suggestions..opinions?

There's no need to change anything other than the jets, unless you already made the jet changes and put the float hight to exactly what's recommended, and you STILL have a problem as read by an A/F meter. Float height effectively changes the emulsion tubes, so set it perfect or you change the off-idle transition (usually for the worse).

Changing the main jet may solve the problem, however it sounds like fuel delivery to me. I ran into the same problem after installing my Weber 45 MCHH. The car seemed to run out of gas under load at higher revs particularly going up a grade. I checked into fuel pumps and found that the original SU on my car, 1975, was a pump that only pumped out 2.7 psi (AZX 1307) there are some SUs that will give you 3.8 psi (AZX 1308) check yours out. Weber told me my carb needed a constant 3.5 psi, plus a higher volume than the SU produces, so I changed to a Carter electronic pump. No more problem.

There is a piece in the library about SUs and pressure etc. see "SU Fuel Pumps 101"

The jet height should be detailed in the links above. Pay close attention to the points of measurement, and wether or nto they specify to have the gasket in place for the measurement. on't do a little more or a little less. Use the exact spec. Measure the float drop height as well. At full drop, it shouldn't be touching the bottom of the float bowl.

Fuel delivery can be a problem, so can 4 jet sizes too lean on the secondary! Remember that the fuel pump won't exactly be a "gusher".