Carb lever issues

[noresull]

Hello all,

First, let me start by saying hey and introducing myself. I currently have a 3year old HPI Nitro MT with a new 12R SS. I have been into R/C for about 5 years, first with an electric car and now my MT.

Enough about me! My question/concern/problem is this. I am having a problem with my carb lever keeps coming loose. I currently have the OFNA throttle linkage kit as shown here I was using this linkage for the past 2 years on the original engine with no issues, but now, after every time I run the truck, near the end of the run, I notice applying the brakes will cause a change in my idle, and upon further inspection, the throttle lever has moved. I tried tightening it up, but it continues to loosen.

Anybody else have this problem or know an idea to fix it?

Thanks

 

[Rolex]

Is it a Slide carb, or a Rotory? I'm not quite sure which part is loosening.
When you apply brake, does the idle get lower? I don't have that engine, but I have access to one that I can look at tomorrow.
If it's a slide carb, with the throttle off, can you push the slide a little further into the carb body? If so, then the slide is sticking, and when the engine is hot, it will move in due to heat expansion of the carb body, which would lower the idle.
If that's not the problem, whatever part keeps getting loose should get some Loctite.

 

[Çh®i§tiªñ]

Can you post a closeup picture of what is moving?

 

[noresull]

It is a rotary carb. Here is a picture of the throttle lever not the best, but You can see the nut that holds it on and that is also the same portion that is loosening.

I have attached the pic. Let me know if You need a better one.

 

[Maxx Trooper]

try some red lock tite on that nut. take the nut off and clean the threads off. put some red loctite on the threads then tighten the nut back down. i hada problem with my fuel inlet coming lose on my trx .15 carb. so i used some loctite and it picked it.

later

 

[noresull]

Yeah, I was thinking about that also. I will try that and get back to ya!

Thanks!

 

[Rolex]

When you reinstall that piece, make sure you press down hard on the carb to seal it tight against the O-ring as you tighten it.
If it isn't pressed down far enough, you'll have an air leak there.

 

[noresull]

Well, I tried the loctite and the adjustment still moved. I guess I'm going to continue and verify the servo isn't losing it's center. They are older and my steering servo is getting weak, so maybe the throttle servo is going away also.

Either way though, I was out playing with it today and I was only able to get 1 1/2 tanks through it before breaking one of my front CVD's, the throttle acting up and I think I have been running my new engine too lean this whole time and screwed it up as it is not running full speed very well after awhile then it starts cutting out on me and not stating again. I ordered a temp gun and CVD repair kit. I w ill not touch the damn thing until I get it fixed and then hopefully I can verify I wasn't running my engine too lean and it's not destroyed. I need a beer!!!:beer:

Thanks for the help!

 

[olds97_lss]

Try putting a lock washer behind the nut so it binds on the throttle arm and doesn't allow it to move on you.

 

[newnitrofan]

Noresull welcome to RCNT I am just making the change to the ofna slide carb linkage with my Nitro mt. I too am running a rotary carb. I should have the carb done this wekeend.

 

[Maxx Trooper]

just thought of something. u know how the OFNA linkage kit has all the different servo attachments for different servos. maby u put the wrong one on for ur servo. i was having a problem at the Florida bash after i bought a new servo after the old one died right on the spot. The Futaba and Hi-tech uses different servo attachments, and i didnt have my other one. so i stuck a piece of electrical tape over the servo then stuck the servo horn on tightened the screw down and i was set to go.http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXBM06&P=7

later

 

[olds97_lss]

It's not on his servo, it's on his carb. On the carb, it's just a pressure fitting between a collar on the carb throttle barrel and the nut that holds it on. I had mine walk around on me on my os 15 cv-r with a rotary carb. I used a small lock washer and it took care of it.

 

[Rolex]

That's an 'aircraft nut' holding it in place. It has a plastic ring on the end of the nut. The acorn looking end. It should grab the threads and keep the nut from moving. I've never had a problem there with any engine, and I don't locktite it. I think you should replace the nut before you end up stripping the threads on the locking rod.

 

[noresull]

Actually, it is not a 'aircraft nut' or a locking nut or nyloc nut. It is just a plain old flat nut. I will get a lock washer to fit and try that once I get it running again.

 

[StaticSag]

Had this prob a couple weeks back on a different engine....maybe your prob can be fixed the same way...by chance does it have a plastic lever? Mine was too thick to let the nut screw down far enuff for the plastic locking device that Rolex mentioned earlier to do its job. I replaced it with a thinner metal one I found on an old Megatech M16 engine which was metal and much thinner. It let the nut screw down enuff to lock and fixed the problem.

Another theory is to make sure your brake End Point Adjustment isn't letting the servo push too hard on the lever when breaks are applied. It will eventualy work it hard enuff to move it.

Hope that helps


Saggy