I have a troy bilt string trimmer, The carb has a metal plate covering the diaphram. The plate has a vent hole in it. I just replaced the primer bulb on this trimmer. When I pump the primer bulb it fills with gas and gas pours out of the vent hole on the plate. I'm thinking this is not right. The trimmer did start. Ran about 4 seconds and stalled. I noticed that the primer bulb was mostly empty. I put the trimmer back in the garage where it proceeded to leak all over the floor. What kind of defect is occurring here?
The metering diaphragm whiich is on the other side of the hole is punctured or not fitted properly
They should always be replace when ever the carb is opened up regardless of what the monkeys on You tube say.
I figured something along those lines. Another thing, I was reading that sitting with old gas will sticky-up the jet. Don't these things have a little needle thingy under the diaphram?
I opened it up. The diaphram does not seem damages and I see no obvious holes. However, the diaphram is stiff. So I'll replace it and the gasket.
#5
sgkent
Is it a Zuma carb? If it is, it may be less costly to just replace it. I can get a new ZUMA carb for maybe $2 more than the full quality rebuild kit, and if the rebuilt kit has a defect, then two kits costs more than a carb. With Zuma carbs, just have to watch the sellers to be sure it is the correct model, new, and not a clone. The price can vary from $20 to $70 for the same model depending on who is selling it. Then when I can find a good rebuild kit at the right price I rebuild the old one and set it aside. Spot prices on their genuine prices are too high but once in awhile someone has a kit they want to sell at a reasonable price.
The diaphragm is what separates the petrol from the air in that chamber .
There is nothing else
So if fuel comes out that hole it is bypassing the diaphragm some how
