What is necessary for jet change of .002 of an inch?

[efwhitacre]

Having troubles finding the jet size I need for a 2001 70hp 2 stroke Johnson. It calls for a 52d main jet. I have two but the other is damaged. Could a guy use a slightly smaller or larger jet size for that particular carb without major harm being done? Thanks for any response, I haven’t really messed with too many carbs. -E-

 

[healey8390]

Having troubles finding the jet size I need for a 2001 70hp 2 stroke Johnson. It calls for a 52d main jet. I have two but the other is damaged. Could a guy use a slightly smaller or larger jet size for that particular carb without major harm being done? Thanks for any response, I haven’t really messed with too many carbs. -E-

It's pulls up as .052", could you could drill a smaller one out?

Edit: Here's a clip of someone hand drilling one:

 

[jimmbo]

Drilling an Orifice is not a Recommended Procedure, as the Original Orifice was likely not drilled, and after drilling, even though the Orifice is now larger, it might actually flow less fuel than prior to drilling

Why are you replacing the Jets in the first place?
You really don't want to be Messing with Carbs on a 2 Stroke, unless you really understand Carburation Theory, as they also determine how much Oil the Engine is getting

 

[efwhitacre]

I have never been able to get this motor to run right. It’ll perform how should (speed wise) for 7 minutes then the motor won’t run over 1500 rpm’s. For whatever reason the mixture in cylinder two is not igniting after a period time. I’m kind of lost so I pulled the carbs. Inside of carb 2 the jet was driven in so gosh darn far I’m suspecting extra fuel is passing between threads. If I wasn’t poor I’d take it to someone but I really can’t afford it. I trouble shooterd the SLOW system and it’s not limiting rpm’s for over heating. I’ve checked spark plugs and they are definitely sparking on all three cylinders. I understand your concern of getting into the carbs but I’m kind of glad I did, I would have never known the jet was so farther in the emulsion tube housing then the others

 

[efwhitacre]

It's pulls up as .052", could you could drill a smaller one out?

Edit: Here's a clip of someone hand drilling one:

I definitely have considered this. I’m just kind of watching eBay for one. That’s really all I need. I got a new bowl, so hopefully one becomes available. The motor it’s self is really nice. Prolly doesn’t have 100 hours on it.

 

[tphoyt]

Maybe look into the strength of your spark after the 7 mins and see what it’s doing. Maybe something is over heating and your dropping that cylinder.

 

[jimmbo]

Can the Spark jump a 3/8" Gap. You will need a tester similar to this


Heat can cause Havoc with Ignition Components. Have you tested for spark, at the time of problem, or once you and the boat were back home, and everything has cooled down?

 

[airshot]

Drilling is not a good idea, the grooves left after drilling can cause flow issues !! Reaming is better as it leaves a smooth finish. Brass is difficult to drill/ ream and can easiky breakoff the tool, just the nature of brass. This comes from a toolmaker with 50 years experience.

 

[Faztbullet]

Jet are reamed to size ..not drilled