float arm sticks open

[jetskiron]

Any idea why a carb needle float arm would be intermittently sticking wide open? I noticed it after engine loading up and I pulled the carb diaphragms off to inspect. This just started on a 2.3 NS I recently purchased new. I used it with a 65 gram spring. It springs back up as soon as I touch it. Needle seat is completely seated.

 

[stagesrt4]

worn out N/S i would pressume

 

[john zigler]

Were they genuine Mikuni needle and seats? Look on the bottom for the Mikuni logo stamp. If it is an off brand, that may be your issue.

I have also seen the needle arm shaft not installed / seated correctly, causing it to bind.

A 2.3 with 65 gram spring is only 15psi for pop off, that is awful low.....

 

[special fx]

Loosen your gas cap while parked......i have to do this with my low pop setup.

 

[Vumad]

Junk hardware or improper install. Only use genuine mikuni carb parts. Mark sure they install and move smoothly. Easy to bind the shaft the arm rests on.

 

[jetskiron]

Thanks everyone. The needle seats are mikuni (little square inside a square logo) and they are brand new. The 65 gram with 2.3 was suggested by Riva. That is what they told me comes on their SBN44 8052 dual carbs. They also told me start with pilot jet of 105 and main of 120. I have been given very different NS, spring, jetting recommendations by other professionals. I have a 98 superjet, 701cc, ported, TNT pipe, 190 compression, lightened flywheel. I am open to suggestions please.

 

[jetskiron]

Anyone know where I can get an EGT and tach gage for carb tuning?

 

[Vumad]

EGT?

I use hardline tachs. $30 and I'm content.

You listed a seat and spring size and not a popoff number. Never assume that your popoff is correct because of what the chart says you should have. Its $30 or $40 for a mikuni tester, or make one cheaper, but test your popoff and make sure your numbers are legit.

 

[Scraggly]

Hard line tach for the win. Love mine great price and great product. Can't tune properly without one.

 

[jetskiron]

EGT gage - Exhaust Gas Temperature gage to see if the fuel mixture is lean or rich. I heard there was a combination gage somewhere that both EGT and tach are measured.

The float arm had a few sharp edges so I filed them down. I will find out later today if it is still sticking open.

Any suggestions on the carb settings for my setup (described in #6 thread reply)?