01-11-2024, 06:24 PM
Agree with Barry (and Les), sounds like a vacuum leak but could be a number of other issues piggybacking to give you grief...
If you have a type 4 engine, check that a rubber elbow isn't cracked or hasn't dislodged from air filter box to the idle circuit .
Other common vaccum leaks include a dodgy one way valve between intake manifold and brake booster., in the engine bay...easy enough to check....undo a clamp and check the one-way valve by sucking opposite to the arrow that indicates flow....it should only permit pressure one way (hence the name
)
Brake booster diaphragm may have failed also....causes a vacuum leak as pressure is not maintained within the booster. How are your brakes ?
As with any engine diagnosis, start simple and work up.
Check all vacuum hoses for integrity and connections, then basic engine setup.....valves set stone cold, points gap (if your running them), carb. mixtures and synch. if you have dual carbs.
A lot of advice will depend on the type of engine you have , so let us know so we can narrow down the potential options.....
If you have a type 4 engine, check that a rubber elbow isn't cracked or hasn't dislodged from air filter box to the idle circuit .
Other common vaccum leaks include a dodgy one way valve between intake manifold and brake booster., in the engine bay...easy enough to check....undo a clamp and check the one-way valve by sucking opposite to the arrow that indicates flow....it should only permit pressure one way (hence the name
)Brake booster diaphragm may have failed also....causes a vacuum leak as pressure is not maintained within the booster. How are your brakes ?
As with any engine diagnosis, start simple and work up.
Check all vacuum hoses for integrity and connections, then basic engine setup.....valves set stone cold, points gap (if your running them), carb. mixtures and synch. if you have dual carbs.
A lot of advice will depend on the type of engine you have , so let us know so we can narrow down the potential options.....
Cheers,
Mark
It’s not oil, it’s sweat from all the horsepower !
Pit crew for : The Tardis - a ‘76 Sopru Campmobile
& Herman - the ‘71 White Low Light
Mark
It’s not oil, it’s sweat from all the horsepower !
Pit crew for : The Tardis - a ‘76 Sopru Campmobile
& Herman - the ‘71 White Low Light