Jerking, hesistating, bogging, at highway speeds

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Jun 25, 2003
Rixeyville, VA
To allreaders,

i have a 1982 fj40 that recently i put a weber carb into. my mechanic says that float in the carb is not working and keeps sticking. the carb is brand new and this seems weird. At highway speeds my cruiser begins to jerk very hard and bog down to the point where i have to stop and start again only to gain about a mile and do it all over again. i have so over 1000 dollars into the whoel carb with installation and custom modification to my intake system. what is the problem. my buddy has pretty much convinced me to screw the weber and buy a rebuilt toyota carb from SOR. Is this a good i dea or should i keep the weber. ???
Re: Jerking, hesistating, bogging, at highway spee

Get a fuel pressure reg, install it, crank it down to I think 2-3 psi, fiddle with it and see what happens. :D
But yes your buddy is right you should have saved $500 bucks and bought a BRAND SPANKIN NEW Aisin. :-/
Re: Jerking, hesistating, bogging, at highway spee

is it the same mechanic who installed it?
just wondering as I installed my own weber and have had no problems with it as of yet
one thing the weber manual says is that you dont adjust it the same as a normal carb, wondering if maybe your mechanic messed it up. did you install new fuel filters as well at the time?
I would have went with Aisin, but I needed a carb right then and couldnt locate one at the time.
check your filters and replace it if it hasnt been done. have a different mechanic look at it that knows something about webers. It doesnt sound like something that should be happening. &nbsp:Did you get a fuel pressure regulator installed?
If so, make sure your getting enough, if not, might want to install one.
Re: Jerking, hesistating, bogging, at highway spee

Check all the rubber lines to make sure that they arrent squishy.....the pressure might be drawin them shut. (don't ask, but it happend on an old belair) Or out of the blue, your choke might be closing up on you for some reason.
sorry for the misfortune.... ???
Re: Jerking, hesistating, bogging, at highway spee

hey I installed a new weber and had the same prob. I think I had it before but Im not sure, anyway it was the fuel
pump that wasn't working right. I got a new one and it was fine.
Re: Jerking, hesistating, bogging, at highway spee

Oh yeah, it may be a gas cap thats not venting properly, but that normally affects all driving, not just highway driving.
Re: Jerking, hesistating, bogging, at highway spee


Your right, i had the stock cabr on it and it started doing this, i first replaced the fuel filter then the fuel pump and then the carb, is it possible that my pump was faulty?
Re: Jerking, hesistating, bogging, at highway spee

how is your filter looking? getting lots of crud in it? might be one thing to check, if your tanks getting old could be getting rusty. check what swamprat said too about the rubber lines.
what kind of fuel pump do you have? stock or electric?
Re: Jerking, hesistating, bogging, at highway spee

Ok, lines are good, just recently replaced the pump with one from ccot, it was the same as stock is. also my mechanic took off my filter and pooored out all the gas and it was clean. maybe tyhe pump is faulty???? i've been using gunk out and gas treatment, maybe my gas line is a little gunked up and when i go to highway speeds it can tpull gas fast enough..
Re: Jerking, hesistating, bogging, at highway spee

I found a faily bad exhuast leak between the exhaust manifold and exhaust pipe. could this be contributing to my problem. could it be timing?
Re: Jerking, hesistating, bogging, at highway spee

If your advance wasn't working right then could be causing that. I had a leak at the manifold so bad it sounded like a rice burner, engine still ran fine.
Re: Jerking, hesistating, bogging, at highway spee


What is causing the exhaust leak at the manifold? A bad gasket? My 40 had an aftermarket exhaust that had a bad exaust leak due to warped headers.. I also had hesitation and miss at WOT and assumed it was carbuerator related.. I rebuilt the carb, and still had the same problem.. it turned out that I not only had an exhaust manifold leak, but an intake manifold leak due to the desinigration of the old Man-a-fre gasket I had on there.. check for vacuum leaks on all your lines.. it may not be fuel related.

Re: Jerking, hesistating, bogging, at highway spee

Alright i know this is going to sound bad since i have 2 fj40's now and worked on them alot but every one keeps telling me to check my vacuum lines and i dont know what a vacuum line is compared to all other things. please help me find whats a vaccum line and what isnt.
Re: Jerking, hesistating, bogging, at highway spee

My fj40 is a '76, and I am unfamilliar w/ all the vacuum lines on an '82, but if your mechanic removed the stock carb and emissions control devices, really the only vacuum lines left existing should be from the distributor to the intake manifold, the egr (left side of the block to the intake manifold), and one to the brake booster.. if I have missed any please chime in! My particular manifold leak was right at the head.. the gasket failed b/w the head and the intake mainiflod.. cruisers are tough b/c the intake and exuast manifold are tied together and use the same gasket.. the only way I found my problem was to remove the carb and manifold and look at the gasket.. follow all the lines coming off the carb and the intake manifold (the piece connected below the carb that attaches to the head). One line coming out of the carb should go to the fuel pump. All other lines need to be checked for leaks.. also check to make sure that there are no little nipples w/out stoppers on them on the intake mainifold where something from the emissions control stuff may have been connected and since removed.. last resort, check the intake manifold gasket.. you might want to check the torques on the manifolds too.. they may have backed off over time.. Hope this helps.


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