1300 with 1800 carb

[LeeMK1]

Hi, I drive a VW Mk1 1300 and recently I had to replace my carb I then found out that it was a 1800 carb. The car drives well with it and has a slight bit more power, I did notice that the revs take Abit longer to come down when I rev the car so what could the problem be and how can I fix it?

[missioner]

Hi, I drive a VW Mk1 1300 and recently I had to replace my carb I then found out that it was a 1800 carb. The car drives well with it and has a slight bit more power, I did notice that the revs take Abit longer to come down when I rev the car so what could the problem be and how can I fix it?

Find the air leak and make sure the throttle cable has enough slack.

[LeeMK1]

Hi, I drive a VW Mk1 1300 and recently I had to replace my carb I then found out that it was a 1800 carb. The car drives well with it and has a slight bit more power, I did notice that the revs take Abit longer to come down when I rev the car so what could the problem be and how can I fix it?

Find the air leak and make sure the throttle cable has enough slack.

Okay so how does a air leak contribute to the revs taking long to come down?? Sorry that's a dumb question but I'm new to all of this so I'm just trying to get as much information as possible.

[missioner]

If there is air leaking into the motor that is not being controlled by the carb it will behave in a way that's not normal. The quickest way to see if this is the case is to start the car and spray the intake with the garden hose, the water being sucked in will cause the engine to stall depending on whether you score a direct hit on the leak or not. This may even help you pinpoint the location of the leak.

This can also be done using starter fluid. Spray the aerosol at the carb and the vacuum pipes, if the revs go up by itself that's where its leaking.

Grab hold of the carb and push and pull it from side to side, it should move, but not much (rubber base gasket). Do this with the engine running, if the idle changes or lifts up there's your leak.

[missioner]

The revs take too long to drop because the extra air is behaving as if the throttle is partially open.

That's also why I suggested you check the slack on the throttle cable. If it's too tight it will prevent the throttle from fully closing.