Do these needle / seat need replacing?

[mbrick]

Working on a carb overhaul for stock motor with dual 38's with Mikuni rebuild kits.

Do these needles need to be replaced? There is a visible ring from the seat on the viton tips. Pop off measures 52psi.
If they seal, run them — or if they have a ring, replace them?

The seat o-ring was leaking on the MAG carb but the Mikuni kit comes with o-rings so that's fixed. Wondering if I should replace the needle/seats with new OEM parts while I am in there, 61X-14916-16-00 about $14/ea, seems lower cost than buying the Mikuni part direct.

First photo is PTO carb, second photo is MAG carb.

 

[///M5]

If they seal at 52 consistently and are soft to the touch they should be good

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[///M5]

If they seal at 52 consistently and are soft to the touch they should be good

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NVM that is a deep ring on them. I would replace now while your in there

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[mikidymac]

You have already come this far, if it was me I would replace them and not have to worry about them for years.

FYI, The OEM ones from Yamaha are cheaper than aftermarket or direct from Mikuni $12.79. THe only thing is they are silver which nobody can explain but they still have the genuine mikuni window stamp.

 

[Quinc]

There was a guy selling a bunch of mikuni 2.5 n/s on ebay for 8$. Save you a few bucks and toss the seat in your parts drawer.

 

[mbrick]

You have already come this far, if it was me I would replace them and not have to worry about them for years.

FYI, The OEM ones from Yamaha are cheaper than aftermarket or direct from Mikuni $12.79. THe only thing is they are silver which nobody can explain but they still have the genuine mikuni window stamp.

Agreed, I'll replace them.

Can you confirm what you mean about the yamaha part? Yamaha 61X-14916-16-00 I listed above is ~$14 and what I plan on ordering. The Mikuni part is $20.

Quinc, thanks for the heads up since the needle is the same. I did a quick search but did not find the seller. If you happen to have a link, lmk.

 

[mikidymac]

I buy my oem parts from Pro Caliber out of Washington. Prices are cheaper and free shipping on orders over $99. And for some stupid reason I always spend more that $99.

The Yamaha part is a genuine mikuni needle and seat 1.5 size for a stock engine. The only difference is for some reason the Yamaha ones are silver instead of the gold brass color and nobody has been able to explain why to me. I just buy them because they are OEM and cheaper.

 

[mikidymac]

 

[mbrick]

Thanks! I ordered two. I'll try scratching one to see if they nickel plated the brass for improved corrosion resistance.

 

[Jr.]

The only problem with the oem part compaired to Mikuni is the coating on the needle. This coating protects the Nitrile from the effects of ethanol.
If you get a load of bad gas, this is one of the parts hit first.

 

[mbrick]

The only problem with the oem part compaired to Mikuni is the coating on the needle. This coating protects the Nitrile from the effects of ethanol.
If you get a load of bad gas, this is one of the parts hit first.

Oh, they are not equivalent parts? Is the Mikuni a viton tip and the Yamaha nitrile?

What do you mean by 'bad gas' in this case?

 

[Jr.]

Excuse me, i ment Viton! My mistake.
By bad gas I mean heavy concentration of ethanol.
They are equivalant parts by Mikuni
Yamaha part is not speced with the coating, the Mikuni direct part is. No other differance.

 

[mbrick]

Okay, I understand, thanks. By that measure pretty much all gas in CA should be considered 'bad' ...

 

[mikidymac]

That is correct, however Mikuni didn't switch to the new coating until just a couple years ago.
I have never had an issue with the standard Nitrile ones here in California. I know Hot Products now defaults to the coated ones but you can still order the Nitrile ones too.

I am sure every new superjet leaves the factory with these Yamaha ones in them.

Also keep in mind these are only the stock 1.5 size so if you need another size then get the newer coated ones.

 

[mbrick]

Got the new OEM parts today and finished buttoning up the carbs. Thanks for the feedback.