nova 91 carby

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M

mark gordon

Member
Joined
Oct 27, 2008
Messages
8
Hi all this is a question to anyone who is running a new nova rossi 91 DD

is anyone having a problem with the carby working loose and slipping out?

I have tried installing it with lock tight, the screw clamp is tight but still works loose.

Any advise or help will be greatly appreciated.
 
Yes. Quite a few times and have gone through 3 carb bolts so far trying to tighten but end up stripping the hex portion. I actually had this problem again recently at a race and stripped another bolt, now have to order more for myself plus replace the one I had to borrow again from a friend at the race. I've informed Ron about this and didn't seem to concerned about it to inform nova, Italy, about the issue. My opinion is that the carb doesn't sit deep enough past the internal o-ring causing it to push it up and out after the engine is running. Ron's cure is to remove the o-ring around the neck of the carb allowing it to settle deeper into the engine. However, if we have to do that to fix the issue, to me that is a design/manufacturer defect of this engine. If something isn't done to correct it, I may end up dropping this engine and go back to running the CMB Evo-101.

Maybe Ron can comment if he's had any conversations with the manufacturer since he's been made aware of this problem and what they plan to do about fixing it.
 
Last edited by a moderator:
I have had one come out on two different motors. This was because I did not get then all the way in. Put a little oil on the o-rings so that it will slip past the bottom o-ring. Now if you still running the carb with the stock barrel you may be bottoming out the stop with the servo. This will spin a carb out of a motor in a hurry. Set your endpoints to where you have bounce in the servo rod when it is wide open. Don't let the servo jam the barrel and put the rod in stress.
 
thanks gentlemen for your replies I hope nova rossi will bring out a bolt

on carby set up .

I also think that this engine vibrates more than any other engine I have use

I had over 8 ops eng and about 16 cmb's and have run them all at high rpm.
 
Mark P Adams said:
Yes. Quite a few times and have gone through 3 carb bolts so far trying to tighten but end up stripping the hex portion. I actually had this problem again recently at a race and stripped another bolt, now have to order more for myself plus replace the one I had to borrow again from a friend at the race. I've informed Ron about this and didn't seem to concerned about it to inform nova, Italy, about the issue. My opinion is that the carb doesn't sit deep enough past the internal o-ring causing it to push it up and out after the engine is running. Ron's cure is to remove the o-ring around the neck of the carb allowing it to settle deeper into the engine. However, if we have to do that to fix the issue, to me that is a design/manufacturer defect of this engine. If something isn't done to correct it, I may end up dropping this engine and go back to running the CMB Evo-101.

Maybe Ron can comment if he's had any conversations with the manufacturer since he's been made aware of this problem and what they plan to do about fixing it.
Click to expand...
Mark,

There is no design defect to this engine. mark has it 100% correct. If you do not seat the carb properly in the embedded oring deep in the carb well, the carb will vibrate loose. If you bottom out the throttle against the end stop while running the engine, that can also make the carb come loose. Posting comments like you are in a public forum does nothing for this hobby and only send negative feedback to the very individuals and companies trying to supply us with engines and equipment for our hobby. If you work hard enough, you can find negative to post about every engine and hull manufacturer present today. The choice all of us have to make is, do we want to be part of the solution and help make all of the products we use in this hobby better, or do we want to stand on the sidelines and throw stones? I can tell you, throwing stones will have a negative effect every time.
 
Mark Bullard said:
I have had one come out on two different motors. This was because I did not get then all the way in. Put a little oil on the o-rings so that it will slip past the bottom o-ring. Now if you still running the carb with the stock barrel you may be bottoming out the stop with the servo. This will spin a carb out of a motor in a hurry. Set your endpoints to where you have bounce in the servo rod when it is wide open. Don't let the servo jam the barrel and put the rod in stress.
Click to expand...
Thank you Mark for positive feedback on how to help correct this issue. I appreciate it.
 
mark gordon said:
thanks gentlemen for your replies I hope nova rossi will bring out a bolt

on carby set up .

I also think that this engine vibrates more than any other engine I have use

I had over 8 ops eng and about 16 cmb's and have run them all at high rpm.
Click to expand...
Mark,

Bolt on carbs present a totally new set of issues. Do you have one of these engines installed and operational? Can you send a pic of your setup? I want to help you figure out why you think this engine vibrates more than any other engine you have used. Frankly, this is the ONLY production 91 engine available today with a balanced, slugged, and tuned crank, unless there is one I am missing.
 
David Ashcroft said:
some feedback is rising to the surface about the 91dd both good and not so good.
Click to expand...

David,

Just like with anything, you need to do your homework. Please let me know what "not so good" other than the posts above you are hearing, so I can work to help correct. Remember, this engine was just a thought under 12 months ago, yet Mr Bullard swept the Huntsville races a few weeks ago in F and Twin Hydro. Also the new 67 that was just a thought less than 6 months ago, also was a winner at that same race.
 
Ron,

Mr. Gordon asked a question and I gave the answer of my experiences since I've been running it. I know for sure that the carb is in past the internal o-ring because I can feel the bump when I push it in to place. After tightening the carb bolt, my thumb has a perfect circle which is the same size as the outside diameter of the carb intake from holding it in place. And, I'm well rehearsed on how to set the end points of push rods. No stones being thrown here, just letting Mr Gordon understand what I have had to deal with. I'm not a engine designer so I don't know the solution to correct the defect.
 
Ron novarossi make probably the best nitro engines available.I have owned a few..

I just think at times it is only fair to highlight any small problems if any..rather than just the very good points..I guess that could only make future engines even better than the great engines they already are.
 
David Ashcroft said:
Ron novarossi make probably the best nitro engines available.I have owned a few..

I just think at times it is only fair to highlight any small problems if any..rather than just the very good points..I guess that could only make future engines even better than the great engines they already are.
Click to expand...
David,

I absolutely agree. There is always room for improvement, and Novarossi is great to work with and are quick to make changes when something is uncovered as an issue. What I don't have time for, and will not participate in, is flat out public forum comments like.... "However, if we have to do that to fix the issue, to me that is a design/manufacturer defect of this engine. If something isn't done to correct it, I may end up dropping this engine and go back to running the CMB Evo-101". Nova is working hard to create "out-of-the-box", race ready engines. Making a comment like that to switch back to an engine, (that needs multiple changes to be competitive), simply because I made a suggestion to remove one oring to see if that helps, does nothing for this hobby. The reason Nova is where they are today, is because they DO listen to feedback. They have gone from concept to production on the 91 DD within one year. They are about to go from concept to production on the new 67 DD within 6 months. How? By listening to the feedback from boaters such as Mark Bullard, Jerry Crowther, Kentley Porter, Martin Truex, Doc Turner, Mike Schindler, Joey Caines, and others, that's how.

All I ask is anytime a possible issue pops up, let me know on here as Mark Gordon did above, (or through email and PM's), and then work with me and others to help rectify the possible issue asap, instead of slamming a product on a public forum and calling the issue a "factory defect" while we are still in the early stages of working together to correct it and determine if the issue is a simple fix or one that needs factory intervention. There may be a simple fix, there may need to be a small factory change which Nova will make swiftly, but we need to show what we did or didn't do or try to do to address it first. We have some of the best boaters in the world running Novarossi engines, and with good feedback we can help make these engines even better.
 
Last edited by a moderator:
mark gordon said:
Hi all this is a question to anyone who is running a new nova rossi 91 DD

is anyone having a problem with the carby working loose and slipping out?

I have tried installing it with lock tight, the screw clamp is tight but still works loose.

Any advise or help will be greatly appreciated.
Click to expand...
Mark Gordon,

Can you email me a pic of the bottom of your engine showing the serial number? I want to see what "manufacturing run" you have. Thanks.
 
Last edited by a moderator:
We have had this problem of the carb clamp coming loose on other engines as well, no matter how tight we made the nut. The clamp eventually deforms the carb or cracks it. Our solution was to drill and tap two holes 180 degrees apart in the housing below the o-ring. We would then put a small flat spot on both sides of the the carb. Be sure to have the carb fully seated when you mark for the flats spots. The flats do not have to be real deep as the diameter of the carb is normally thin. Put the carb into the housing making sure it is seated and the flats are lined up, tighten the clamp nut to hold it in place. Locktite the set screws and tighten them enough to hold the carb but not deform the carb. I would recommend using cup point set screws. Works for us, hope it works for you. Good Luck!!!!!!!!!!!
 
The K&B clamp nut works killer.........................had to use one on the MAC/CMB .21 eng as the CMB nut was junk................

Had to drill the threw hole out a little but it never cam lose again.

Some nut are better than others........................
default_wacko.png
 
Last edited by a moderator:
That has been a problem for all engines that I have seen back in the late 90's we used to red locktite blue locktite sleve retainer our carbs and also two part epoxy and glue the carb I have even used jb weld. It sounds like all you need is a case hardened bolt were the hex wont strip out. Sometimes it is the simpliest thing that can fix a problem. Rc 90 boat.
 
RonShaw said:
David Ashcroft said:
some feedback is rising to the surface about the 91dd both good and not so good.
Click to expand...
David,

Just like with anything, you need to do your homework. Please let me know what "not so good" other than the posts above you are hearing, so I can work to help correct. Remember, this engine was just a thought under 12 months ago, yet Mr Bullard swept the Huntsville races a few weeks ago in F and Twin Hydro. Also the new 67 that was just a thought less than 6 months ago, also was a winner at that same race.
Click to expand...
. Ron, Mark Bullard did indeed finish his heats and won f hydro with his novi 91, but he did not run twin and twin was won with cmb 80's . I won 2nd place f hydro with 75 points. Marks 67 did look very good for an out of the box engine.
 
RonShaw said:
David Ashcroft said:
Ron novarossi make probably the best nitro engines available.I have owned a few..

I just think at times it is only fair to highlight any small problems if any..rather than just the very good points..I guess that could only make future engines even better than the great engines they already are.
Click to expand...
David,

I absolutely agree. There is always room for improvement, and Novarossi is great to work with and are quick to make changes when something is uncovered as an issue. What I don't have time for, and will not participate in, is flat out public forum comments like.... "However, if we have to do that to fix the issue, to me that is a design/manufacturer defect of this engine. If something isn't done to correct it, I may end up dropping this engine and go back to running the CMB Evo-101". Nova is working hard to create "out-of-the-box", race ready engines. Making a comment like that to switch back to an engine, (that needs multiple changes to be competitive), simply because I made a suggestion to remove one oring to see if that helps, does nothing for this hobby. The reason Nova is where they are today, is because they DO listen to feedback. They have gone from concept to production on the 91 DD within one year. They are about to go from concept to production on the new 67 DD within 6 months. How? By listening to the feedback from boaters such as Mark Bullard, Jerry Crowther, Kentley Porter, Martin Truex, Doc Turner, Mike Schindler, Joey Caines, and others, that's how.

All I ask is anytime a possible issue pops up, let me know on here as Mark Gordon did above, (or through email and PM's), and then work with me and others to help rectify the possible issue asap, instead of slamming a product on a public forum and calling the issue a "factory defect" while we are still in the early stages of working together to correct it and determine if the issue is a simple fix or one that needs factory intervention. There may be a simple fix, there may need to be a small factory change which Nova will make swiftly, but we need to show what we did or didn't do or try to do to address it first. We have some of the best boaters in the world running Novarossi engines, and with good feedback we can help make these engines even better.
Click to expand...
. I'm very happy novi is building marine engines. I just started running a novi 46 and I'm excited about it. I do feel future engines with bolt on carbs with no low speed needle would please the buyers in the us the best. The engine could be cheaper without those parts also. Mac engines sold like hot cakes with no low speed needle.
 
been running model boats of all types and sizes since 1992. i KNOW 3 things as facts.

bolt on (above .21)

no low speed

360 rotating carb (allows option of being operated from other side for “special” installs)
 

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