Important and popular mod for the Nova 46 carb

[Glenn Quarles]

Friends, with the talk about the barrel retaining screw in the old style .46 carbs breaking, I just wanted to make sure you got the word to remove the spring from behind the barrel. This is very important to ease the pressure on the screw and even more important to prevent the spring from getting sucked down into the motor in case the barrel backs out while it is running! All you need to do is remove the retaining screw we are talking about, pull the barrel out, remove the spring from the inside of the carb, and then put it back together. This will make your carb HAPPY, HAPPY, HAPPY!

I even do this on the new carbs with the larger bolt.

Please let me know if you are having trouble with the retaining screw wearing and I will send new ones when I get them in September.

GQ

 

[James E Beasley]

What do we do in the mean time to prevent the retaining screw from backing out, locktite? Do we all have old style carbs or ? Can you tell the carb based on SN or ? James

 

[Jose F Cid]

James,

What I do is use locktite (red) and then I take finger nail polish and put it over the screw this way is the screw backs out I can tell right away and correct it.

The main problem that I had was the tip of the screw breaking off so Glen will be sending me a few screws mines happen to be 3mm screws I believe that the first were 2mm but I'm not sure of that. I

just removed that spring that is a great idea as I got lucky this past weekend that the spring did not go into my motor.

good luck,

Jose

 

[Glenn Quarles]

What do we do in the mean time to prevent the retaining screw from backing out, locktite? Do we all have old style carbs or ? Can you tell the carb based on SN or ? James

James, I dont use anything on the screw and have never had one back out. If you want to put a little locktite on it that will be OK. No all the latest motors have the new size screws, but I can't tell the exact date they made the change. No the motor SN wont tell. All you need to do is measure the screw, if it is 3mm then it is the old one, 4mm then it's the new one.

GQ

 

[Glenn Quarles]

James,

What I do is use locktite (red) and then I take finger nail polish and put it over the screw this way is the screw backs out I can tell right away and correct it.

The main problem that I had was the tip of the screw breaking off so Glen will be sending me a few screws mines happen to be 3mm screws I believe that the first were 2mm but I'm not sure of that. I

just removed that spring that is a great idea as I got lucky this past weekend that the spring did not go into my motor.

good luck,

Jose

Jose, yours is one of the original ones, the new ones are 4mm.

GQ

 

[Jose F Cid]

Great,

Thanks for all your help.

Jose

 

[Blackout]

I'm kinda surprised a 3mm alloy screw would break under those stresses. Looked at mine this morning to see what is going on, but still need to take the carb apart. I wonder if the screws break from debris in the barrel channel causing it to jam up. Otherwise there are very little stresses in that area in my mind. Just thinking out loud here.

 

[Glenn Quarles]

I'm kinda surprised a 3mm alloy screw would break under those stresses. Looked at mine this morning to see what is going on, but still need to take the carb apart. I wonder if the screws break from debris in the barrel channel causing it to jam up. Otherwise there are very little stresses in that area in my mind. Just thinking out loud here.

Yeah, it is hard to tell why some have broken??? I'm sure there are some high freq vibs going on, but maybe some boats have bigger shakes than others (balance of props, etc), or it may be that some linkages are applying pressure at the high and/or low throttle positions adding extra stress???? I have never had one break so I really can't say for sure.

GQ

 

[Jose F Cid]

Guys,

I here you, but this is a new motor that I have taken very good care of.

I know for a fact that it is not the props or the boat itself the carb looks great and there were no burrs or anything on the carb barrel.

I have no idea what caused it to break off after I get the new one if this happens again and you guys have not had that problem then I will go back and check the boat again. Just thinking has anyone else had this happen to them???

Thanks for all your help,

Jose

 

[Glenn Quarles]

Guys,

I here you, but this is a new motor that I have taken very good care of.

I know for a fact that it is not the props or the boat itself the carb looks great and there were no burrs or anything on the carb barrel.

I have no idea what caused it to break off after I get the new one if this happens again and you guys have not had that problem then I will go back and check the boat again. Just thinking has anyone else had this happen to them???

Thanks for all your help,

Jose

Jose, I didn't mean to imply that anybody was doing anything wrong, I was just thinking of the different things that may cause the screw to break.

GQ

 

[James E Beasley]

Even the OS 46VRM was notorious for vibrating the throttle barrel set screw out. Saw plenty of them eat a screw and lock/blow up. It's vibration, plain and simple. NR has always made top quality engines, but this is their first attempt at a 7.5 cc outboard. There are reported incidents of cases coming loose from the PTO, multiple start cone thrown offs, and now carb screws coming out. My take is engine balance, no brainer. The Nelson Outboard is a similar case. The designer builder converts them from engines primarily designed for use as airplane pylon racing engines. I have tried and know many people that have tried to keep a muffler bolted on to it. They break the bolts off of the muffler like butter. In time maybe NR will do more research on this matter and find the exact problem. I am sure Glenn is conveying all of this info to their engineers and if not cost prohibtive they will make some mods, maybe balance the crank better and dynamically match the flywheel. Nelson had to do that on his engines. Since the NR46 is the only new 7.5 OB available we can't be real picky, we can just work with it and NR to get it right. Not trying to beat up the engine or Glenn, just conveying my thoughts. My OB is doing fine for now after first throwing the start cone. Fast as hell too. James Beasley

 

[Jose F Cid]

Glenn,

no problem I know as helpful as you have been nothing was implied!!! I did not take it that way. I'm not sure but I was thinking after that maybe taking the spring off as you asked me to do might help it. The vibration coupled with the sping is putting more tension on the barrel on to the screw and maybe this might cause it to break off. This is just me thinking, however I would like to know if anyone else that has this motor has had the same problem.

Thanks,

Jose

 

[Greg Bonahoom]

I have broken two screws and had them vibrate out a couple of times as well. I am now employing a "servo saver" to make sure there is not to much pressure on the high/low throttle position.

Thank you Glenn for working to get this issue straightened out. These motors are wicked fast!

 

[barry petrowski]

Had this happen last year when first came out. Sucked in spring and trashed motor. Glenn and Nova were great in taking care of problem. I now remove springs in 20 motors also just in case. I can't see any use of keeping them in. If you were to lose a clevis at carb, spring pushes barrel to the open position. Also when tightening carb arm hold nut I don't let stop screw hold barrel while tightening,use wooden dowl through carb to hold barrel.

 

[Tim Kish]

I'm kinda surprised a 3mm alloy screw would break under those stresses. Looked at mine this morning to see what is going on, but still need to take the carb apart. I wonder if the screws break from debris in the barrel channel causing it to jam up. Otherwise there are very little stresses in that area in my mind. Just thinking out loud here.

Yeah, it is hard to tell why some have broken??? I'm sure there are some high freq vibs going on, but maybe some boats have bigger shakes than others (balance of props, etc), or it may be that some linkages are applying pressure at the high and/or low throttle positions adding extra stress???? I have never had one break so I really can't say for sure.

GQ

Have they been tested for hardness?

Possibly to hard and brittle ?

Tim

 

[Rokieboater]

Guys,

I here you, but this is a new motor that I have taken very good care of.

I know for a fact that it is not the props or the boat itself the carb looks great and there were no burrs or anything on the carb barrel.

I have no idea what caused it to break off after I get the new one if this happens again and you guys have not had that problem then I will go back and check the boat again. Just thinking has anyone else had this happen to them???

Thanks for all your help,

Jose

Jose, I didn't mean to imply that anybody was doing anything wrong, I was just thinking of the different things that may cause the screw to break.

GQ

Glenn,

keep me in mind when you get the screws in.

Thanks,

Robert