Cold start exhaust system.

[splitpin]

My bongo has cold start device in exhaust, can this be checked to make sure is working correctly and is not jammed in either position.
Thanks.

[Simon Jones]

When you turn on the switch there should be a change in the sound of the engine. If you rev it up you may get a sound a bit like a belt slipping.

[haydn callow]

I get a whistling noise from our bongo exaust when revved...What other symptoms do you get if this valve is not working properly ?? apart from the noise it seems to run the same as ever.

[haydn callow]

where is everyone???
Help ??

[haydn callow]

been out playing with mine....when I press the switch...not a lot happens...I can hear a click but the engine note hardly changes if at all....when I switch off I hear a click from the valve and some mechinical noise....Bongo goes well....would it go well if the valve was not fully open ?? when revving I get a whistle....not belts or No1 stud. This appeared stright after having a exaust section replaced and I put the whistle down to a slight leak which I cannot detect.

[Doone]

When ours was jammed, the symptoms were lack of power (flat) and the fuel consumption increased (only 17miles to the gallon!!). There was no whistle from the exhaust when the valve was playing up. The engine note never changed much when it was/wasn't working, but we did have a big bore centre and rear exhaust, so may sound different. Al has heard from people who have asked him for advice after they have replaced their own exhaust section and have a whistle (with and without the exhaust valve) and no leaks. It's usually the centre section; he thinks the baffles may be slightly out of line, but they do carbon up and the whistle goes.

[haydn callow]

Thanks for that.....Somthing to do with the baffels had crossed my mind....Also I was hoping it would go away but we do very little mileage.

[haydn callow]

I've looked at exausts on e bay to see if you can just take the "valve" out and put in a bit of normal exaust...can anyone point me at the required bit ??
Thanks

[splitpin]

When you turn on the switch there should be a change in the sound of the engine. If you rev it up you may get a sound a bit like a belt slipping.

Thanks for reply Simon, do you mean if is not working properly will get belt slipping noise when revved. Says in book when device is switched on is only active while idling, when revs build up is deactivated. Haven't noticed any change in engine sound when switch pressed or any clicks from exhaust.
Regards

[mikeonb4c]

When ours was jammed, the symptoms were lack of power (flat) and the fuel consumption increased (only 17miles to the gallon!!).

Interesting this and it would be good to get the view of a pilot (e.g. Bob). Its just come back to me, but I recall the light aircraft I flew in with my pilot mate had an option to feed hot air into the carburettor to prevent carb. icing when conditions were likely to cause it. The downside was loss of power, presumably due to lower air density reducing the quantity of oxygen available for the combustion process. Does the Bongo device have a similar effect, albeit that it is being done to warm the engine, not prevent carb. icing!?

[splitpin]

Interesting this and it would be good to get the view of a pilot (e.g. Bob). Its just come back to me, but I recall the light aircraft I flew in with my pilot mate had an option to feed hot air into the carburettor to prevent carb. icing when conditions were likely to cause it. The downside was loss of power, presumably due to lower air density reducing the quantity of oxygen available for the combustion process. Does the Bongo device have a similar effect, albeit that it is being done to warm the engine, not prevent carb. icing!?

Think it just partially blocks exhaust, causing engine to work harder for quick warm up, doesn't affect air being taken into engine.

[mikeonb4c]

Interesting this and it would be good to get the view of a pilot (e.g. Bob). Its just come back to me, but I recall the light aircraft I flew in with my pilot mate had an option to feed hot air into the carburettor to prevent carb. icing when conditions were likely to cause it. The downside was loss of power, presumably due to lower air density reducing the quantity of oxygen available for the combustion process. Does the Bongo device have a similar effect, albeit that it is being done to warm the engine, not prevent carb. icing!?

Think it just partially blocks exhaust, causing engine to work harder for quick warm up, doesn't affect air being taken into engine.

Blimey! Nothing fancy then. Maybe I should carry a potato to stick over me tailpipe in case of emergency (no rude replies please )