Nova 45 DD going lean?

[Terry Keeley]

Having problems with Olly's SP40 going lean to the point it surges at full throttle, on the stand it's rich enough it hardly cleans out.

He's gone to large lines and shortened them, moved the tank closer, bypassed the 3rd channel needle all to no avail. Tank is sound with no leaks.

It's gotten better with the above changes but still not good. Another club member is having similar issues with one in a JAE.

Anyone else?

 

[mark ham]

I had trouble with a Picco like that, put a sealed bearing on the crank and fixed it.

 

[Ron Zaker Jr]

porous exhaust elbow when hot??? I noted that some are wrapping the elbow with high tape.

 

[Tim Kish]

DD straight header Ron.

 

[MattMurany]

What pipe is he running?

 

[John Beardslee]

Ron, he's running a DD so no elbow.

Terry did you check for cracked case? Is this a new engine? The first ones out had a weak case and NR has since redesigned them.

Thanks, John

 

[Ron Zaker Jr]

DD straight header Ron.

missed that.

 

[Tim Kish]

We have changed everything possible including three different pipes.Lines tanks, header seals , everything.

Real head scratcher, latest version DD .

 

[Marty Davis]

We drilled out the spray bar on the carb that a couple of the guys that I run with have.

 

[Glenn Quarles]

Terry, they like to run really rich on the beach, but if you have enough load and heat in it they will clean out and scream on the water. I often have to keep mine at about full throttle while carrying it down to the water to keep it running, but 10 feet after launch it is on like donkey kong!

It may need tighter head clearance (should be about .009"), more heat in the head, more prop load or maybe pulling some coils on the plug. All of these will help it clean out when you richen the needle.

GQ

 

[Brandon Atwell]

A lot like the issues I've been having lately with my outboard .46.

It is pain to get it to clear out on the stand making it seem like it's extremely rich, but once it is in the water it makes it maybe bouy 2 and dies. Tried leaning, fattening, changed props, aswell as doing what you said Glenn. Nothing helps.

Starting to wonder if maybe the motors are just that touchy, and don't like the humidity we have in the South? When's it's colder out ive noticed it runs best with no finicky issues.

 

[Terry Keeley]

What pipe is he running?

NR 45 muffled pipe. We've pulled it out to 10 1/4". No blockage of pressure lines etc. Good seal on the header, coupler etc.

Ron, he's running a DD so no elbow.

Terry did you check for cracked case? Is this a new engine? The first ones out had a weak case and NR has since redesigned them.

Thanks, John

He's looked it over, don't think so. Where were they cracking?

We drilled out the spray bar on the carb that a couple of the guys that I run with have.

Will check that, Steve Wood prepped the motor, I know he cut the low end out. Carb seems a bit big at 11mm with only a small spray bar left. Olly noted it's sitting up higher than most with the ramped intake, could that be part of it?

Terry, they like to run really rich on the beach, but if you have enough load and heat in it they will clean out and scream on the water. I often have to keep mine at about full throttle while carrying it down to the water to keep it running, but 10 feet after launch it is on like donkey kong!

It may need tighter head clearance (should be about .009"), more heat in the head, more prop load or maybe pulling some coils on the plug. All of these will help it clean out when you richen the needle.

GQ

It's so rich on the stand it hardly cleans out, needs to be about 2/3rd throttle or better to keep running.

We checked the head clearance, it's about 0.010" so don't think that's it.

Don't think it's running too cool in his enclosed SP40, no airflow at all, seems hot if anything so we ran it without the cowl and it was better. Might be getting hot due to the lean condition tho.

We switched from a cold OD blue to a K&B HP with a coil pulled and it was better.

It just seems to have a problem feeding enough fuel to it...

 

[Tim Kish]

Terry, they like to run really rich on the beach, but if you have enough load and heat in it they will clean out and scream on the water. I often have to keep mine at about full throttle while carrying it down to the water to keep it running, but 10 feet after launch it is on like donkey kong!

It may need tighter head clearance (should be about .009"), more heat in the head, more prop load or maybe pulling some coils on the plug. All of these will help it clean out when you richen the needle.

GQ

Glenn

We are running rich as well, motor runs great for 3/4 of the tank then starts surging, doesn't matter how hard you run it.

We ran it wide open and on the lean side and it still did the exact same thing.

The only thing that has helped a little was adding a 1 0z hopper and that just delayed the surging long enough to finish the race.

Tim

 

[John Beardslee]

Mine run pretty rich on the stand too but I'd still like to hear what pipe Olly's running and what size the stinger dia. is. I run so little water that it comes in just sizzling. Do the sport 40 guys have similar tank set ups and issues that the 1/8 scale do. The early NR cases cracked around the large dia. crank bearing from mount lug to mount lug. The new style case has a wide rib running fore and aft. I've never heard of anyone having a problem with the new style case.

John

 

[Terry Keeley]

Mine run pretty rich on the stand too but I'd still like to hear what pipe Olly's running and what size the stinger dia. is. I run so little water that it comes in just sizzling. Do the sport 40 guys have similar tank set ups and issues that the 1/8 scale do. The early NR cases cracked around the large dia. crank bearing from mount lug to mount lug. The new style case has a wide rib running fore and aft. I've never heard of anyone having a problem with the new style case.

John

NR 45 muffled pipe, stinger dia. is about 0.350". Seems to work for others.

I'll get him to check for cracks...

 

[Glenn Quarles]

Yeah there have been zero cracks with the new cases. I wish I could help you guys more, but I have never experienced the problems you are having. When you get it figured out let me know what it was so I can let other guys know!

GQ

 

[Jeff Schindler]

Check for cracks right where the serial number is stamped on the bottom of the case.

I just built an engine with a new case and it was going lean on me too. I cut my tank apart but no issues there. I think my issues are with the Bob Voilett needle base mounted to the engine rails. The rails vibrate the needle. I put a remote needle in and it ran hard as it ever has; hoping that wasn't just a fluke. My experience is just with the wrap around header and the NR46 Quiet pipe. My boat seems to like the pipe really short or it falls off down the straight as if it was sagging. My pipe is approx 9 1/2 inches to the start of the cone.

Edit: Boat flows about 40 or less on the Boris Gen3 meter. Idle on the bank is about half open, and once on the water I need to back it down to really go slow.

 

[John Beardslee]

I run the same pipe with no issues, 9-1/2 is a good place to start.

John

 

[dave roach]

Terry

Check the spray bar and make sure that it pointed the wright way. I had one it was facing the wrong way.

Dave

 

[SayMikey]

What prop are you running? Just asking is there a oring at carb bottom in case?