engine troubles!



'74 fj40, 1F/2fhead, weber carb

So, I'm having a problem- the engine is difficult to start, and dies when giving it gas, especially when easing the throttle up. I can goose it and get it to rev about 1/3 times. Once its warmed up it idles better, but still dies if you give it a little gas. Also, it smells a little rich, but that could be due to revving it a bit. I replaced the fuel pump a couple days ago, and it does run a *little* stronger.

Any ideas?

Oct 11, 2002
Denver, CO
Two things come to my mind...

First off, check the fuel filter & inlet screen (not sure if the Weber's have these) where the fuel line goes to the carb.  The old stock fuel tank in my FJ40 was rusting out pretty bad.  I could get it to start up, but as soon as I gave it any gas, it would suck up too much rust, completely plug up the fuel filter, and kill the engine.

The second would be the exact opposite side...that you are getting too much fuel.  This could be a by product of a needle valve being stuck opened or the float being stuck in a down position.  If you believe this is the problem, you can try pouring a bottle of Heet directly into the carburetor, let it sit for a couple of minutes, and then fire it up.  The chemicals in Heet have a way of loosening up varnish & other things that may be gumming up the carburetor.  If it fires up, it will smoke (a white smoke...so don't do this in a closed garage...heh) pretty good for a minute or so, but it will clear up once it gets to running on straight gasoline again.

Hope that helps...


Dec 13, 2002
Knee deep in hookers and gin
Sounds like the carb, although it could be other things.

What do the plugs look like. Carbon black? too lean white?
Maybe a massive vac leak. How does it run when you choke off the carb throats? Does the accelerator pump work? with the engine off look down the carb and pump the throttle. You should get a strong stream of fuel. If not you have a bad accelerator pump or no fuel in the float bowl. I assume you have changed the fuel filter. You can try a fuel volume test to see if the pump is pumping. Put the hose to the carb in a bottle and turn the engine over with the coil wire off and grounded. There is a spec for volume, but it's pretty obvoius when there is a problem.
Too rich might be float stuck. You might see dripping down the carb throat at idle. Tap on the carb with a hammer and you might loosen it up.
Hope it gives you some things to try.
Jan 3, 2003
McCall, ID
Could the timing being off do this? How about the vacuum advance hose disconnected?
Oct 31, 2002
Kennett Square
I have seen numerous discussions on the web similar to this one. So I'll ask the same question here as I do there (and maybe here before). Are you running a fuel pressure regulator ? Webers, at least all the ones I have tuned over the years only like 2.5~3 lbs. of pressure. When new you can get away without one but as time goes by so do your float needles and seats causing too much fuel and all the ills and joys associated with flooding. From you post the only thing you've done is replaced a tired fuel pump. At any rate the first thing to do when tuning your weber is give it what it wants.

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