On the Meerkat I've cleaned the carb, replaced fuel line and put in a filter.

Following the sticky I have set up the carb and can get it idling nicely with excellent throttle response.

However soon as 1st gear is engaged and any throttle causes the engine to bog down and die. If it is able to get moving its very lumpy and jerky.

Is just more carb tuning required or do I have to start looking elsewhere now like the CDI

 

it's not the CDI, put it up on blocks and tie it down or hang the rearend from the ceiling. start it and rev it up with the rear axle off of the ground, does it do the same thing? does it do it in neutral? if in gear and it does it, may start looking at clutch, if it does it in neutral, it's a vacuum/fuel delivery issue like a partially clogged main jet.

 

Just a thought, how about compression?

 

How does the vacuum side of these carbs work, is it connected to the inlet manifold? I got the quad with the running issues so there may have been something missing or connected wrong to start with

Thanks for the help

 

as your slide or butterfly on your carb opens, the lower pressure sucks in more air as more gasoline is sent to piston via the carb. the carb is trying to maintain the ratio. when it bogs down when the throttle is pressed, you're demanding more fuel, right? well, with a partially clogged/plugged jet, the gasoline demand is not met BUT you still have more air coming in offsetting the ratio. NOW, fuel demand is not met to sustain the burn and the quad bogs. does that make sense? hope so, i got cramps from typing. but anyways, that is a fuel delivery issue that needs to be rectified. to test for vacuum leaks at the intake boot, let it idle, spray carb cleaner or ether-starting fluid around the outside of the intake boot-not the airbox side. if it revs up, you have a vacuum leak that sucked in the vapors and fed the piston downstream of the carb. could be as simple as making sure the flange/O-Ring is on correctly or replacing the intake boot.

 

The vac from the manifold goes to the petcock. Once the motor is turned over/started vac is made and it's supposed to open a diaphram in the petcock that allows fuel to flow.
You can suck on the vac hose and see if fuel runs out of the petcock.
Could the pipe be plugged?
Whatcha think on that compression??

 

i didn't know that about the vacuum on the petcock valve. thanks! i learned something there. i just presumed it was gravity flow based on float output/demand. yeah, i agree on the compression!

 

Thanks for the replies chaps, much appreciated

Couple things that I've done/noticed that may help.....

1) Only line from the petcock (fuel tap over here!) is to the carb, no vac line at all

2) The carb has the fuel line going in, and a pipe from the float bowl that just goes down towards the ground, I assume for draining the bowl? There are no other pipes attached, take it this is how it should be?

3) I jacked up the rear and and can go through the gears no problem though once in 4th and apply throttle from low down it starts to bog a little

4) On idle it is smooth apart from a reasonable regular 'pop' or misfire. I took the plug out and its looks like a crappy non-branded thing.

5) Don't have a compression tester. I cranked the starter with my finger over the plug hole and couldn't hold it down, was getting pushed out by the compression. Not ideal but I assume that shows compression is reasonable?

6) After it bogged down and cut out the plug is wet with fuel.

I am thinking maybe it could be a simple as the plug? Maybe when more fuel is going in under load the demand for a stronger spark is not being supplied through the plug and it runs excessively rich? Could be way off but trying to think of all the options

 

some guys have had success with a new $3 NGK spark plug. SO, it's worth the investment! take that old plug and find a comparable NGK(or whatever name brand y'all got there). it can work. we helped a forum member recently that had some spark issues etc.....$3 and 2 days later, he was happy and running! we can get you to try that and then go from there.

 

I've ordered a couple of NGK plugs, nice to have a spare!

Once one is in we can see what happens