How can i drill out the main jet in my weed eater's carburetor?

Question

How can i drill out the main jet in my weed eater's carburetor?

Answer 1

Not to be a wet blanket here on everybody's enthusiasm to enlarge via drill. Before you go drilling out your extra jets there maybe a problem doing it this way. A drill will leave a spiraling grove that will cause the matter passing through that to swirl. My understanding on the carbs is that this could disrupt the normal flow. Look at the smoothness of the present jet hole and compare it to any drilled hole. How much this would effect overall operation would be anyone guess and would greatly depend on the accuracy of the hole and sharpness of the drill bit among other things. Also, are the jet holes bored or are they drilled? My bet would be towards a mill vise or a drill press.



I am not saying that drilling is wrong but I have heard this from quite a few mechanics that have much more experience in this, than I, reccommend against it for those reasons.



Remember that the size is #50 is .50mm .120 is 1.20mm. etc.

After some measureing I've calculated that you can use the following drill bits to come close to the sizes needed, or actually be bang on with many of them. So here goes. Remember that a jet marked 120 is 1.20mm in size, 135 is 1.35mm etc. Perhaps those who know more accurately can correct me if I'm way out on this, but I think I'm close.











50 #76

55 #74 approx.

60 #73

65 #71 approx.

70 #70

75 #69 approx.

80 #68

85 #66 approx.

90 #65

95 #63

100 #61

105 #59

110 #57

120 3/64th's

130 #55

140 #54 150 #53

160 1/16th's

165 #52 approx.

170 #51

180 #50

185 #49

195 #48

200 #47

205 #46

210 #45

220 #44

225 #43

230 #43 approx (close to 225)

245 #41

250 #40

I reccomend 1size larger at a time.Go by the colour of the plugs after use.possibly two sizes at a time may not be too much. Remember if you go too large you can solder it back in and redrill.





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Answer 2

find a small engine shop in your area. they will be able to order any size jet you need, or even a different carb. these small ones arent to expensive and a jet should be real cheap and you would have a precision jet that would perform better than a home modified one.



just curious, why alcohol? i now racers use it, but not for horse power. it makes the engine run cooler. i would stick with gas. its cheaper than rubbing alcohol.

Answer 3

ther'e more to it than just the main jet,to run methanol,u need to also enlarge,the idle circuit,and the midrange circuit,and them hole are super small compared to ur main circuit,u just have to experiment,if u drill the holes to big,it's not a problem,cause it's easy to solder the holes shut and start over,,,,and there is such thing as jet drill's,my brotherinlaw uses a set in his small engine shop...

Answer 4

exelent advice from davecat but i would probobly go 1 bit size at a time... better not enough than too much

Answer 5

What davecat said. He got here first, but was pretty much my answer, too.

Answer 6

just drilling the jet bigger not going to help you, you will be just flooding the engine, you want to wreck your engine go ahead. thats why the make engines in different HP according to the work load. dont waste your time and money

Answer 7

Take the carb off the engine and take it completely apart find the main fuel jet in which the fuel flows then get a set of small percision drill bits (at any hardware store) find the bit that fits in the main jet then go up about 4 drill bit sizes and try that if it is still being starved for fuel then go up another bit size until you get it right......