912 carb rubber flanges

[peterholmes]

hi all

 

I have a dta 912 microlight, on my 300 hourly service I decided the original carb rubber mounts/ flanges needed replacing, its a std 912 with the two bing carbys, ordered them via bert floods, good delivery service, installed them no problem, until I went to run the engine, as soon as it warmed up, with no choke the carbs started to flood, with fuel comiing from the overflow tubes, I discussed the issue with "major millard" and he came down to the airfield and we checked out both carbs, needle and seats were ok, and we noted that the rubbers were alot stiffer than the other 912 engines in the hanger, I have since adjusted the float levels but I am still wondering why just by changing the flanges that this problem occurred,

 

so to you mechanics out there, give me your theories????????:confused:

 

 

[facthunter]

carb. rubbers.

 

Flooding in the circumstances you describe, is most likely related to vibration of the carburettors. If the "new" rubbers are fairly old stock, then they may have become harder and altered the vibration dampening characteristics of the rubbers.. Nev

 

 

[bones]

I agree with Nev, i changed mine at 850 hrs and no probs.

 

Hey Pete was it you this morning in the towers, i just missed you all, you were leaving as i got there, oh well i will get down to Mont soon.

 

 

[peterholmes]

gidday bones

 

yes it was the gaggle of DTA microlights in "the Towers" , we had a awesome flight and my engine ran well, but i wonder if the rubbers logically soften with use, my problem seems to be getting better..........

 

will send you a message when we are heading your way, or if you are coming to town my email is [email protected]

 

cheers

 

 

[barandbrew]

HI peter

 

I have just changed the rubber flanges on my Gazelle and guess what

 

The motor wouldnt idle without advancing the throtle even though the only thing changed was the flanges and after a short run the motor flooded with fuel pouring out the overflow we spent hours trying to work out what we had done wrong finally putting the old flanges back on and presto all was fine again.

 

I will be calling Floods on Monday and sure hope they have a solution. The new rubber is way stiffer than the old.

 

John

 

 

[peterholmes]

gidday john

 

hope you get an answer from bert flood, and post your reply here, it would be useful info.

 

maj millard did say that rotax may be stiffening the rubber as maybe the soft rubber doesn't last very long,

 

my problem seems to be improving as the weather gets colder, the extra rich mixture?? may help??? but the carbs are not flooding now, and the rubbers seem to be easing up.

 

:thumb_up:

 

 

[alf jessup]

While attempting to remove left carby bowl on a friends 912 to check and fill the bowl as it hadn't been started in 3 months I put the very slightest upward pressure on the carby and the rubber flange pulled out from the mounting plate to the manifold.

 

Very surprised by the amount of pressure i applied to the carby while trying to get the bowl clip off for it to do this.

 

The machine has only done 160hrs TT, luckily for me I had 2 spares as i changed mine out recently just for the sake of changing them.

 

Could have been a fault with this flange as I have appleid far more pressure to mine and never had a problem, the rubber that failed still looked looked brand new.

 

Puzzling !!!!!

 

Cheers

 

Alf

 

 

[bra83d]

Any answer on the flooding issue from floods????

 

 

[facthunter]

expectation.

 

Are you expecting floods of information from floods on flooding? nev

 

 

[pudestcon]

Are you expecting floods of information from floods on flooding? nev

I thought with climate change we could expect less rain so therefore less floods! Wot you on about Nev?

 

Pud