Predator 670 carb help again!

[slonomo]

I do know the Vanguards also use different sized jets. I don't remember which side was which. You could probably scour the forum here and figure that out. I think it has to do with the length of the intake runner.

So if your jets are on the engine side, that's the fuel side. Your pilot jets will adjust the amount of fuel that pass through them. The amount of air will be the same, just the amount of fuel is adjustable. Most start with 2 turns out as a starting point. Remember not to fully seat those screws as you could damage the tip of the adjuster, just touching is fully closed, don't turn it hard.

[chazdo2]

thanks again I got the manual and crossed referenced the part numbers to find out which jet goes where. Thanks a ton will fire it up today!!!

[slonomo]

Good luck

[chazdo2]

No luck the screws are on the engine side and I closed them right off! I looked them up and they are on the proper side 105 on the left 108 on the right. Still running way too rich gas in the intake plenum as it runs. Im at my wits end here any more suggestions? Float is not sticking. Maybe adjust it a lot lower?

[slonomo]

Did you try and adjust them the other way?

[chazdo2]

Can I make up some lie how I miraculously fixed the problem like I figured an abstract problem out? Or do I tell ya the truth you were right backing those screws out ( " L and R" capped screws) is making the difference! Thanks a ton again and not giving up on me!!!!!!!

Addendum: Got the " L " and " R " screws backed out 5 turns!!! Still too rich but no longer flooding out the intake plenum. Is running better but the screws must be close to all the way out! Should I change out the main jets?

[slonomo]

Those must be air circuits. Don't run them 5 turns out, they might vibrate loose and fall out. I think you need smaller pilot jets. Most pilot jets are good from say 1 turn out to about 3 turns out. Any more than that and they are beyond what they are designed for.

I would recommend that you read up on carbs/jetting so that you can better understand what you are adjusting. Google "carb tuning" and look for some videos. You can really learn a lot from watching a couple good ones.

The idea is this: (disclaimer: rpm is not accurate, for illustration only)

Pilot Jets = idle up to say 2000 rpm

Midrange Jets = 1500 - 3000 rpm

Main Jets = 2500 rpm to 4500 rpm / or full throttle

Each jet adds to the next, so at 1500 rpm, the midrange jets kick in with the pilot jets, and at 2500 the main jets kick in with the Mid and Pilot. So at full throttle, all 3 circuits are adding fuel.

Hopefully this makes sense.

[slonomo]

One thing you might need to do is clean out the pilot jets. These are the smallest jets in the carb. Sometimes they are plugged up from years of buildup, sometimes it's just a spec of sand/dirt. If you haven't done this, it might be part of your issue. Also, the same applies to the main jets.

Here's a video of a Vanguard carb. It's different from what you have, but for informational purposes it will let you see how these things work.
https://www.youtube.com/watch?v=xOliwvhFsY0

Removal of the pilot jets is tricky. You have to make sure you use the correct screwdriver or you'll strip out the head. You want the largest slotted screwdriver that will fit into the slot.

[chazdo2]

thanks again!!!