• Hi Guest!
    If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

zenith stromberg 175 cd

Share this page

M

mtlman8

Jedi Trainee
Country flag
Offline
I am going to replace leaking throttle shaft bushings this week. any tips?
 
Lube the new ones. Sometimes they fit pretty tight around the shaft, so much so that they may bind the shaft and keep the throttle disc from returning to idle position
 
So... I DON'T NEED BUSHINGS (8.99) and I don't need a hundred dollar reamer?????
 
nevermind my last post. I did'nt read all the way through.
 
mtlman8 said:
So... I DON'T NEED BUSHINGS (8.99) and I don't need a hundred dollar reamer?????
Click to expand...

Probably not. Usually the bronze shaft takes the wear.
 
But these are ZS carbs, the throttle shaft seals should take care of any leaks. .
 
just picked up the bushings. thanks for the tips,let you know how it turns out.
 
NO MORE THROTTLE SHAFT LEAK! But it still won't run.fuel pump is new and electric (2.5 -4.5psi) carbs have been rebuilt. It wants to run, it fires but won't run, but if i lift the piston in the first carb (how high does'nt seem to matter)it will run for about 10 to 15 seconds. i'm pretty darn sure the floats are set correct, but i'm stuck... please help!
 
The fuel pressure is a little higher than recommended for those carbs. 1.5 to 2.5 is recommended. are there symptoms of flooding ?
Remove the air filters and look into the carbs while the fuel pump is running. If you see gas coming out of the jet when the pump but not the engine is running, it's flooding.
Eliminate that possibility before proceding with other troubleshooting.
 
BTW, it would help if you could provide the version of the carb you have. There should be a brass or copper tag on the top cover with numbers and a letter for identification.
 
no tag on the carbs, but i'll check to see if they are flooding.if they are is it a fuel pressure issue?
 
Good possibility since the fuel pressure is so high. If you are flooding and bringing the pressure down to 2# doesn't cure it, there are other things you can check, but it's best to eliminate one suspect at a time.
 
OK! went and bought the correct fuel pump today. 1.5-2.5 psi. tested it and it is putting out 2.5psi, but it still wants to run but won't, again if I lift the piston in the first carb I can get her to run for about 10-15 seconds... WHAT GIVES????could it be timing? it fires and you can hear it wants to start but won't.
 
Lifting the piston leans the mixture without changing the timing; so it sure sounds like it is way too rich for some reason.

Are you sure the pistons are installed the right way around? There are tabs on the rubber diaphragm that should match notches in the piston & body, but sometimes they get overlooked. A diaphragm with a hole or crack would cause problems, too.

If I recall correctly, the ZS carbs on a 4A would have a "cold start bar", that would cause the mixture to be way rich if it were turned to the "choke" position.

Maybe the float is "sunk" (meaning it has absorbed fuel and become too heavy to hold the float valve closed when the bowl is full).

I don't recall offhand how the float bowl vents are routed on a 4A, but you need to be certain they are open to the atmosphere.
 
the diaphrams are new and they have a tab that seats into the carb.the pistons are in correct if the two holes at the bottom are supposed to be to the rear of the carb. whats the best way to tell if the floats are sunk?BTW THANX FOR THE INFO.
 
and that Dow Corning is the PERFECT lube for non rubber suspension bushings....
 
Back
Top