7 port Nr and stock carb. Question.

[tmunn]

Are any of you guys using the stock carb and remote needle adjusting arm/ assembly that comes on the NR 7 port.

I have been using the carb that glenn modded for for my 5 port on my 7 port and want to try the stock carb for the 7 port, on the 7port.I like the fact that it will idle and start well using the stock carb without pinching lines and blipping the throttle to keep it running.However Glenn suggested to avoid midrange lean settings I may have to cut off the LSN on the stock carb.

What have you guys that run the stock carb experienced.

It will be in a 21 jae rigger and will be WOT most of the time if that matters...lol..

Thanks guys.

terry

 

[Baxter Walton]

Well as for me I never use a stock carb, but they can be used as Glenn did modify you one. My personal experience with stock carbs for racing I will not use them, I much rather pay the extra and find a after market one. Some times a stock carb from another motor will work just fine on a different motor, like the O.S. carbs for example. To keep it simple I would just ask Glenn to mod that carb for the 7port motor. check and see if the two carbs are the same. They just very well might be, and in that case you are not missing any thing. just my thoughts.

Baxter

 

[Duck899]

I have been using the stock carb from an AA/21 on my nova-rossi 5 port and it works well. Very compact carb.

 

[Blackout]

I run a bone stock carb on a NR 5-port in my JAE .21 and it works well for me. Probably not the fastest, but the engine starts like a dream. No priming, just put the starter on the belt and the engine is running in seconds. Starts easier than a gas boat.... With a 7 3/4" pipe length I can bring the boat to a literal crawl and then still get back up on pipe. Works great for my novice driving skills.

 

[Chris Wood]

i have used the stock nova carb for over 10yrs same carb with all the low speed junk gutted and never ever had a problem. works great good size i never seen any reason to change. but that is me

chris

 

[Baxter Walton]

Oh yeah if you gut them(mod) they can work just fine. As is the way that they come from the factory, they seem a little touchy. Hey Chris I am liking those Blackbirds! I was going to get one just before I got out of boating but never did, I will PM you sorry for getting off topic.

 

[tmunn]

Chris,

Why is it necessary to remove the low speed junk and do you leave the HSN side alone(leave the spray bar in tack).I figure if the modded carb flowed the same as the stock carb at WOT then i "should" get the same top speed but still learning.

Anyone,

What would be the noticable differences between the carb glenn mods and the stock one.

I guess i just better get out and test some.I had a 21 cmb that had the hsn and lsn in tack and i thought it worked perfect but it was my first higher end race motor....

 

[Chris Wood]

i removed all the low speed as i don't use it.. it blocks air.. or at least i think so.. the spray bar has to be modded and a few other things. but it works.. simple as that.. my dad does the mods to them and there are others out there that have them they seam to work fine as well.

it is a personal preference on what you like.. marty davis i know used to and maybe still does use lowspeed needles

take that for what it is

 

[tmunn]

Thanks i will get back on here once i try it and see how it works bone stock first.

 

[shoboat]

Terry,

Zoom-21 Carb all the way.

There is nothing like them on the market.

Good Luck,

Mark Sholund

 

[Tim Kish]

Hey Terry

Was a lot of fun hangin with you last weekend.

In the past people went to after market carbs mainly because of poor design and or to small of a bore size.

Most carbs today are very good with only a minor mod to them they work great , some need nothing at all.

On my 7 port I have tried four different carbs , an Orlic , stock Nova, D&J and a Nova modified by Mr Wood.

I would have to say that the Nova mod is as good as any of them and the best part is it comes with the engine.

You watched my boat last weekend and know that its not the fastest out there but it's not slow either.

I don't have any problems starting the engine or keeping it running , Now buoy's are another story LOL.

I think once you get the needle a little closer alot of your start up problems will go away , but I also think that teasting to see the results yourself is more important than anything , thats how we learn.

Tim K

 

[Mike Larson]

Steve Woods' work on the box carb works great.... I've used speedmaster and DJ, modified CMB, whatever.... depending on your needle location, per Os/Ferrete, Cmdi whatever.... it's a preference thing.... He does nice work, and it costs like 40 bucks but you dont have a 6 foot wide carburator in the boat either..... See him maybe at Hobart. Mike

 

[tmunn]

I will try the stock carb out this weekend if the weather permits and let you guys know how it goes.I will take the modded carb from my 5 port with me if it does not go too well with the stocker.I also feel if the stock carb will work and i can make use of the mixture control on the HSN then it should be more responsive than my other one that was located much farther than from the carb.I think if it works as well as the other remote needle it would have to be more responsive since it is right on the carb.

You guys removing the low speed or cutting it off are you using the mixture control that is right on the carb with your 3rd channel or another brand or another brand of needle ??

Tim , Very nice hanging with you also and i agree that my troubles will be less once i get the needle close.I also want to see how the stock carb works and try to use the mixing that is located on the hsn and also get rid of some of my fuel line by doing so...Just playing around for now ....

 

[Chris Wood]

on mine i have all the stuff removed and use a remote needle seperate.. in 20 boats there is no room and having that mounted on the carb it will end up hanging right at our outside the boat.

 

[Brian Sorgente]

Back when the first series of long stroke engines came out (I think this was back in like 2000-2001?) I ran a bone stock NR long stroke in a microburst mono (with the stock carb). The only thing I did to the engine was lower the deck height.

The boat was fast but definitely had carb issues. It would surge heavily when you hit around 1/2-3/4 throttle, after you got through the hiccups in the midrange at got to WOT, if you closed the throttle slightly after being wide open, It would stage right up and pick up substantial speed.

We tried everything to fix this (without modifying anything), thought the boat might be too lean but it would just do the same thing when we made it too rich, tried different pipes, moved the LSN all over the place, checked all seals & fuel lines, etc... After many sessions of testing we eventually narrowed it down to the carb.

After I saw everyone else modifying their NR carbs I figured this was not a coincidence. The stock carb looks like a nice unit, but from what we found, there seemed to be something funky with the spray bar setup that hurt performance. After that same carb was modified all of these issues went away. Granted the entire engine was modified along with the carb but since then, I've run that same carb on several other engines over the years and never had the issue again.

I'd be interested to hear whether you have similar issues when you try the bone stock setup on your engine.

Are you going to be at the next race?

Brian

 

[tmunn]

Thanks Brian, That kinda sounds like what Glenn was explaining to me.When you modded the carb. what did you do and were you able to use the stock mixture control valve with your mods or just how did you make your mods and what 3rd channel did you use.Looks like I may have jumped the gun by switching carbs.

Yes I plan to make the next race In CT.

 

[moparbarn]

i ended up with one of these carbs on a cmb TT in a mono i bought. talked to glenn q. about it, the mods he described basically turned it into a carb with just a spraybar extending about 1/2 way into the bore, no low speed needle, & needing a remote/third channel needle. i just put a stock cmb .21 carb on it, because that was what glen's mods would make it virtually identical to.

 

[Brian Sorgente]

Thanks Brian, That kinda sounds like what Glenn was explaining to me.When you modded the carb. what did you do and were you able to use the stock mixture control valve with your mods or just how did you make your mods and what 3rd channel did you use.Looks like I may have jumped the gun by switching carbs.

Yes I plan to make the next race In CT.

Well I didnt do the carb, Andy Brown did, but the high and low speed needles were removed completely. The hole for the high speed needle was plugged with solder and a remote needle was installed in the boat. I believe the spray bar was cut to extend only to the center of the carb throat as well.

Im intersted in trying another NR carb and keeping the high speed needle it comes with on it. I'd remove the low speed for sure though. Either that or remove everything and install an OS valve setup on the side of the carb like I did with my .12 carb but thats a bit more work.

See you next week,

Brian

 

[tmunn]

Thanks guys lots to think about for sure.I have been starting the motor with the stock carb installed and it starts and idles VERY nice but if it is going to go lean and not run well I will have to make some mods to this carb OR but the other carb back on and go back to the DF base and OS needle.I just wanted to try the stock carb and it looked like a nice unit and i already cut the tub on the right side to clear the HSN ...no biggy.

 

[gil sonsino]

Hi Terry What Brian said about Andy's mods is exactly what I use to do to all my NR and Picco carbs...I haven' t had too much sucess with the stock ones but they work for a time ..you will figure out what's better for you. In these pics you wil see a mod I use to do to my 12 NR carbs using an OS needle in the place of the original fuel nipple...it can be done the same way for the .21 NR. carbs too.

Gill