Hey guys, just wondering if anyone does any jetting/tuning or tinkering around with their carbs. I have a 23sd. It's a small engine and lacks the balls, but I get pretty decent speeds and rpms when I drive with a light load.

My question is when I bought the mikuni, it came jetted (of course) I thought the main jet was too small. (Felt that I was running too lean, according to plugs looking white) so I upsized. And yes I saw results. Should I keep going or do you guys think that they do enough research and development inorder to know what main jet size produces the overall best results? Anyone still run stock jets?

Also, how do y'all set your throttle cables up. Wide open? (Meaning slide goes fully up to the top) or do you leave a little space? And the slide remains showing.
Currently mines remains showing maybe a 1/4 inch from the top. A buddy told me to leave it like that inorder to keep the vaccum... I don't know if this is correct. Any input would be appreciated thanks in advance.

For the slide travel I set mine to open all the way.

I picked one up for around 200 that came with every attachment known to man. It's got a code reader in it too and since I work with cars for a living, it serves multiple purposes. Takes all the guess work out of tuning a carb for sure..

I'm be looking at these. That would take all the guess work out if tuning

I didn't see any good deals right now, but they pop up from time to time. Watch ebay. The innovate LM-1 and LM-2 seem to both be pretty good. I got the LM-2 and it came with the exhaust clamp, inductive tach, ODB plug, hard plastic carrying case..pretty much every accessory they make for it, for right around 200. If you buy new, it's a little over 200 for the meter with the 02 sensor, and around 75 for the clamp. They also come with a bung you can have welded to your exhaust, and not have to use the clamp.

Thanks going to keep my eye out

You need to have a bung in the exhaust for that I think. I don't have one.
So I'm guess y'all do tune your toys!
Good then ill keep at it.
Atleast I know I can pull the slide up all the way. Thanks

You don't want the slide set above the barrel of the carb if that's what you're asking. When all the way open, the opening should be completely round. The slide should not slide up out of the barrel. It should sit flush. It will create turbulence if not set correctly.

Hmmm thats good stuff

Maybe I misunderstood the question. I thought he was asking about adjusting the slide itself. After re-reading, it looks like he was asking if he should set his throttle to open all the way...which should be a no brainer.

Ok. I'll check it out.

Yeah the slide will be fully open. And not too far up so that the needle won't seat properly.

What do u mean by turbulence?
Loss of hp, because the slide is open too high?

If open to far it'll create like a vortex( like your bathtub drain) in the carb and you'll get inadequate fuel/air flow

Yes, you should set your throttle cable to open the carb all the way, if that was your original question.

There is also an adjustment for the slide on the carb. It should be set flush. If it's set too high, you'll create a pocket for turbulence.

Yeah ill set it flush. It's a pretty easy thing to do. And I'm going hunting in a few hours. Woohoo! I'll see how it performs!

My questions were:
1. Does the bps carb kit come jetted correctly? In your professional opinions! Lol
2. Does anyone here jet there own carbs?
3. The slide question which y'all answered.
4. Do I continue messing with this thing?

I jet my own carb and no they do not always come jetted properly, i can't really remember what jet they come with i think like a 170 or something. They don't know whats done to your motor or if its stock when they sell you the kit.

Clay correct me if im wrong

They can't all come jetted correctly. They shoot for close. If you ordered directly from MB, it probably came with whatever they ship them with. If you ordered from BoatDr, he may have changed some things depending on what other mods you have and your elevation.

Short answer, no.
Everyone who installs a carb should check to make sure it's jetted properly.
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You should read the tuning manual for your carb. You should mess with it until it's right.

Since its a 23 we're talking about, are you running a VM carb or HSR?

Gotcha! Mines came with a 180. Main jet. I upgraded it to 190 and saw more top end. My spark plug reading is marshmallow tan now. Some white spots still remain though.. Might be getting close. Might have to upgrade pilot aswell.

I just realized he has a 23hp my comments are directed towards the 42 hsr

If you aren't cutting the plug, you aren't really reading it.

Info should be pretty interchangeable, turbo.

I thought they used a tm34?

Reading it off the base ring is plenty good enough to get it where you want it without cutting the plug IMO anyway...I never look at the porcelain unless there are little metal specks on it

I mean, it is a lawnmower motor, which we lose sight of all the time

Well, I don't have a nascar to play with!!

Quit ruining the fun!!

I thought bending the float tab was a "hell no!" I don't think my engine is starving for fuel. I mean idk how much is in the bowl while I'm running it "wot" but Ill check It out. My carb main jet is a hex. Not the small one. I shop on jetsrus.com idk if it's a com or hsr. Sorry

Don't hate on the 23 lol. Its a pos! Lmao easy to move when it gets stuck though. Light and easy!

I don't cut the plugs.

Yeah I get it. It's a law mower engine. But I still wanna have a badass tiny 23 lawnmower/generator engine! That passes everyone else's boat! Gosh I'm so competitive! Soon it will be a 35 or better. But we gotta start somewhere

Ideally i'd say in the header pipes, one on each side, but its too hot. Put mine in the center of the can, on top.

You want it in the top half of the pipe (muffler body) ideally. If you put it at 6 o'clock there could be an issue with condensation fouling the sensor.

You don't know

Im a good guesser!!