Outer Limits 4x4 Board

just wondering if anyone could help me with a problem ive got with my rrc. the engine is a 3.5l and the other nite it started to play up. i lost all power, started running really rough and i had to put it into low range to make it to the nearest servo. ive since got it home and when you start it from cold it runs normal but as soon as it heats up it coughs and splutters and has no power at all. sounds like it has a huge miss/ running lean but its got spark to all plugs and theres fuel in the carby bowls. i dont know what else to look for.....

just uploaded a short video of what is happening, its pretty crap quality but u can kind of hear it towards the end what is happening.

visit http://www.youtube.com/watch?v=0mkJKi8fpf4

The video quality is poor I can even tell what kind of carbs you have.

If they are Solex type, take the inlets off and check that the pistons lift when you increase the revs. The rubber diaphragms on top of the pistons often split, with similar results to what you have.

The other thing that happens with old rangies is the rubbing block for the points wear rapidly and the gap closes up. But usually they get harder to start (and thirstier) before you notice a significant loss of power.

cheers for the reply, if what you say is correct then i reckon its the first problem. the second (points) i dont think affects me due to having electronic igntion. if that rubber diaphragm is split does the carbie lube piston fail to build pressure? i was toping up the carbs with machine oil and noticed then when i was checking the fill ( manual states to push down and resistance (pressure) should be felt a couple of threads above the socket) the passangers side seems to not build pressure and sounded like it was escaping from somewhere.....

Silver_pig_gq wrote:cheers for the reply, if what you say is correct then i reckon its the first problem. the second (points) i dont think affects me due to having electronic igntion. if that rubber diaphragm is split does the carbie lube piston fail to build pressure? i was toping up the carbs with machine oil and noticed then when i was checking the fill ( manual states to push down and resistance (pressure) should be felt a couple of threads above the socket) the passangers side seems to not build pressure and sounded like it was escaping from somewhere.....

What you are calling a lube piston is the dampener. It should have a light oil. The dampener runs inside a tube that is part of the piston I was referring to.

On the bottom of the piston is the tapered needle for the main fuel jet. As air flow increases it creates vacuum which lifts the piston, hence the needle. As the needle rises it allows more fuel through the main jet to suit the increased air flow.

There are 4 screws holding the top housing (with the cap that you unscrew to remove the dampener) onto the carby. Remove the top housing and you will see the diaphragm attached to the top of the piston.

Just checked the diaphragms for both carbs, they seem to be in good nick with no cuts or tears and no pershing. the screws looked a bit threaded that i took off so id say someone has changed them previous to me. any other ideas?

If it is electronic ignition it might be the ignition module?
It should be in a case off the side of the dizzy retained by 2 screws.
I have over time found that rangies with electronic ignition seem to foul up the rotor button. A quick clean with some sand paper and comes good.

have tried that, the ignition is not attached to the dissy itself, but off to the side mounted on the guard. lumeneux (spelling?) is the brand. needless to say ive cleaned the rotor button, plugs, checked the leads, all plugs are getting spark and the carbs are getting fuel.

Silver_pig_gq wrote:have tried that, the ignition is not attached to the dissy itself, but off to the side mounted on the guard. lumeneux (spelling?) is the brand. needless to say ive cleaned the rotor button, plugs, checked the leads, all plugs are getting spark and the carbs are getting fuel.

What does look like of spark plug :- brown, oil, rust or too rich black?

drivers side plugs where nice and clean, maybe a tiny bit white but not much at all, and the passenger side plugs where all black and soot covered, i just rubbed them back with sandpaper and put em back in. is it possible the problem is the carbs? what other setups can i run to fuel the 3.5L?