Main jets

[5150abf]

Okay, it's winter here in Indiana, I am messing with my boat, I go to clean the main jets and a 1/16 drill bit will almost fit, I mean by a thousandth of an inch.
What would happen if I made the jets that little bit bigger?
I am working on a 1981 50 Evinrude and the jets are 550's.
I am pretty sure I already know the answer(DON"T DO IT !!!) but I thought I would seek more informed opinions.
On the other hand jets are pretty cheap and it can't hurt the engine to run rich and it may run better so what do we think?
Thanks

 

[tashasdaddy]

Re: Main jets

don't do it.

 

[HighTrim]

Re: Main jets

Since the 'jet' meters fuel depending on the air velocity moving through the venturi, boring it would lead to incorrect fuel/air mixtures. The motor is engineered to run at the jet od provided, and unless you are experienced in this, should not be attempted as Tash said.

 

[5150abf]

Re: Main jets

That is what I thought,I will clean them out and put it back together.
Thanks.

 

[R.Johnson]

Re: Main jets

If cleaning jets with a drill bit, It is a good idea to have both the drill, and jet chart for reference, along with a micrometer. You can't always trust a drill to be the size as stamped, you will find this often with the low priced drills. What I use for cleaning, or checking jets is a wire, or pin guage held in a pin vice, but this would be over-kill for the person just doing their own carbs.

 

[iwombat]

Re: Main jets

I'm still of the opinion of never putting anything harder than bronze through the jet orifice. I know you guys on the board do it all the time though. If I have to put something through the hole I use dental floss or thread.

 

[5150abf]

Re: Main jets

I wound up using a stripped stranded copper wire because it is easy to pull strands back until it is just the right size.
I am still curious what it would do but it is already put back together.
Thanks

 

[iwombat]

Re: Main jets

Copper is softer than bronze, so it really can't harm the jet.

 

[R.Johnson]

Re: Main jets

As a mechanic, you use your head as well as your hands. Cleaning a jet without damage should not take a second thought.