HELP for Queenie's mower

[Dink]

we went through the bike and did all normal maintenence and contact cleaning etc. feeling confident that all was in readiness we put it into the local dealer for a carb balance and service before she rode it.
All went well until they tried to get a stable idle, discovered a slight crack in a carb diaphram and a leaking fuel tap diaphram so these were replaced with new genuine components, everything was reset and try again.
Now we can get a stable idle so long as the vacuum hose is diconnected from the fuel tap as soon as it is reconnected the idle goes erratic and rough,
Any ideas or suggestions? even our mechanic admits he is stumped
Dink

[focus frenzy]

sounds like the petcock was not put back together correctly, or posibly a vacume leak in the line.

[Dink]

the replacement tap was a complete new genuine assembly, not sure about whether the line was replaced though
Dink
thanks for the quick response Leon

[focus frenzy]

after having the "mower" running, pull the vacume line at the carburator and check for gas in the line. It should not have gas in it!

[earlfor]

Re: HELP for Queenie's mower

The first thing that comes to my mind Dink is maybe they replaced the fuel tap diaphram with the incorrect one. A part that physically will fit but is not the same part number may not work.

Earl

[quote="Dink"]
All went well until they tried to get a stable idle, discovered a slight crack in a carb diaphram and a leaking fuel tap diaphram so these were replaced with new genuine components, everything was reset and try again.

[WifeofDink]

Re: HELP for Queenie's mower

The first thing that comes to my mind Dink is maybe they replaced the fuel tap diaphram with the incorrect one. A part that physically will fit but is not the same part number may not work.

Earl

The fuel tap was replaced with a complete new one as there was fuel in the vacumm line.

[Anonymous]

Re: HELP for Queenie's mower

Now we can get a stable idle so long as the vacuum hose is diconnected from the fuel tap as soon as it is reconnected the idle goes erratic and rough,
Any ideas or suggestions? even our mechanic admits he is stumped
Dink

What happens when you take the line off and block it up?

So far it sounds like you are getting stable idle with an open vacuum line. Have I misunderstood that? Perhaps you have a blocked air jet (or something ) and the open vacuum line is compensating.

Kim

[Anonymous]

Kim
When the vacume line is removed from the petcok and is plugged. the thing idles correctly--this was my understanding from a conversation with Duncan last night.

[redliner1973]

Kim
When the vacume line is removed from the petcok and is plugged. the thing idles correctly--this was my understanding from a conversation with Duncan last night.

In that case it sounds like a bad petcock slipped through the quality control dept......this is provided it ran OK before.

[earlfor]

Re: HELP for Queenie's mower

Have you tried running the engine with the petcock vacum hooked up and the gas cap off the gas tank? A plugged gas tank vent is a possibility. (still scratching my head :-) )

Earl

The fuel tap was replaced with a complete new one as there was fuel in the vacumm line.