mcculloch weed eater carb probelems

[jr dragster Tyler]

Hi, I have a mcculoch 2816 weed eater engine and I am having some carb probelems It was working fine a few days ago and it just started to act up. It has a walbro carburater with 2 fuel inlets one on the back and one on the front of the carb beside to hi/lo ajustments. My problem is is that there are air bubbles coming out from the carb from the fuel inlet on the front. Any know whats going on? I cant put a pic of the carb but if you google search mcculloch 2816 walbro then you will find it. Any help is greatly appretiated.

I hope I didnt stump even the best of you guys I was thinking it needed a carb rebuild kit.

[kibble]

One of them isn't really a fuel inlet as far as I'm concerned. When you push the primer button, fuel gets pulled into one of them and the excess goes out the other. I guess just wait for Russ to reply and see what he says. :biggrin5:

[Russ2251]

Does engine actually run poorly or is it that you noticed air bubbles and assumed it is a problem?
Rebuilding is probably not going to fix air bubbles. I would only remove/disassemble carb as a last resort.
Check all tubing for splits/cracks especially around any kinks in lines. See if you can spot where bubbles originate from.
There is a 'clunk' (resembles aquarium air stone and is common in r/c model airplanes) on end of fuel line in tank that sometimes can separate. This 'clunk' serves 2 purposes. It is a fuel filter and a weight that keeps end of tubing at bottom of tank regardless of position of trimmer. If this 'clunk' breaks off it could end up sucking air because it is no longer submerged in fuel.

[jr dragster Tyler]

No the engine just started to run poorly russ. and kible the second inlet actually sucks up fuel. And the bubble's are actually coming out from the carb on the inlet beside the mixture screews. And If I prime it the engine runs for about a minute then starts to run poorly. The carb is not sucking in the fuel from the 1 inlet then bubbles start to from from the carb. And I have tried by passing the primer and it still doesnt suck the fuel in

[Russ2251]

Could be internal leakage (diaphragms). Rebuild kits may be hard to come by. Carb for this (I think) may be specific to this machine/engine. Macs are funny that way. Kits are sometimes more expensive than original carb.
Before attempting rebuild, see if you can replace all tubing and clunk. Eliminate all other possibilities of leakage.
Also, I have seen replacement carbs on Ebay (see link) which are manufactured by Zama and pretty much a knock off of your Walbro WT and may be cheaper than rebuild kit.
Without this in my hands it is difficult to diagnose. I tried.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&Item=360029584399&Category=79674&_trksid=p3907.m29

[jr dragster Tyler]

Thx I will try that.