twin mac 84 problems

[Terry Keeley]

1/16" ID x 1/16" cross section or -003, available anywhere.

 

[Drew St. Amant]

Awesome thanks guys we'll probably pull apart the needles tomorrow I can't get any trash to come out of the tank so it could be the needles themselves

 

[Walt Barney]

1/16" ID x 1/16" cross section or -003, available anywhere.

Any hydraulic repair shop should have them 003 is the correct number the cost is about .25 each I normally buy about a box full at a time 100 in a pack.
Walt Barney

 

[Tom Foley]

Does anyone know where I can get O rings for my needles if I knew what size I they are I could probably get them from McMaster

FLscale boater has the part #

 

[Bradley Maglinger]

O Ring <---- This is what I use

 

[FloridaScaleBoater]

FLscale boater has the part #

Not for the Violet/Barr needles
I do have for the Russian K/AA needles

 

[Drew St. Amant]

Ok so I got some orings on the way. Here is some picture of the needles, there is definitely some trash in them nothing major from what I see but I bet filters would have made this not a problem so I'm thinking my solution is clean these and add filters

 

[Roxyflash]

Are the needles plumbed correctly?Side nipple to tank bottom nipple to carb?

 

[dwilfong]

When you check the flow with your meter wiggle the top of the needle and see what it dose.

 

[Drew St. Amant]

The needles are plumbed opposite of how roxyflash mentioned I thought I had done them like that in the past without issues but now that I'm thinking about it all my other bout are plumbed with the bottom to the carb could that be whole issue?

 

[Danny King]

The needles are plumbed opposite of how roxyflash mentioned I thought I had done them like that in the past without issues but now that I'm thinking about it all my other bout are plumbed with the bottom to the carb could that be whole issue?

The needles will work in either direction. Just have to flow them to the correct numbers. But they will meter just fine either way.

The BV needles are high flowing and will work in either direction. Some of the smaller needles need to flow a certain way to flow enough fuel for bigger engines. But on your app the BV will glow fine in either direction for Mac 84 engines.

 

[Drew St. Amant]

OK the way we have the needles setup it would be very hard to plumb them the other way so I'm glad to hear that

 

[Roxyflash]

I just used a Stu needle which is very similar to the bob violet there’s instructions with it that says to plumb it a certain way if you look at most carbs the fuel tapers down the needle toward the port of intake.Not trying to disrespect what others are saying just following instructions from the Stu needle vavle.

 

[Steve White]

Inline fuel filters!

+1 on fuel filters.

Also, be sure and clean the exhaust system or it could be blowing crap through the pressure lines.

 

[Drew St. Amant]

Never thought about the exhaust pushing stuff in the tank not a bad point but the pipes are actually brand new that day was the first run on them

 

[Ray Sametz]

Never thought about the exhaust pushing stuff in the tank not a bad point but the pipes are actually brand new that day was the first run on them

Even brand new, they can have filings from the factory.

 

[Timbo Whalen]

When you check the flow with your meter wiggle the top of the needle and see what it dose.

Air leak....good point. All it takes is an o-ring that's sat around dry for awhile.

 

[dwilfong]

Not looking for an air leak when the needles get old and a little worn the flow will change just from vibrations. That's why I said wiggle the needle when you're running a flow meter and see if the flow rates change. A loose fit will let the needle inner part wiggle and it will change the flow.

 

[Drew St. Amant]

So we found the issue and got it fixed and turns out it was a really dumb issue all of our hydros except this one have a plug and the second water outlet and a hole in the head like normal well this boat has a 90 fiting in the front as a outlet well it was loosing up a little from vibration and spraying water right into the carb I'll post a running video soon

 

[Drew St. Amant]

I found a old thread from 2018 that said you use cmb 80hr piston and liners in a 84 is this still the case or does anyone have experience with this?