Nova 45 DD going lean?

[Glenn Quarles]

One other thing I have seen twice in the last week with Sport hydros…are you sure you are getting PLENTY of air into the cowling?

Last weekend Kelly Gruel was running his new brand sport 40 with a wrap around Nova and I don't think it ever made much more than one lap for the first 5 or 6 times he tried it. We went to a smaller carb and did many of the things talked about in this thread…nothing made a difference. He mentioned several times his concern about weather it was getting enough air inside, so we ran it without the cowling and BINGO, it ran perfect for an entire tank! Awesome find! Then yesterday I was out with Jerry D while he was running his sport 20 with a .21DD in it. At times since he first finished this boat it has run awesome…at other times it was kinda a pain and took constant tweaking of the needle and amount of water cooling. It would run good for a few laps and then fall off and just start acting weird. I suggest he run it with out the cowling and again BINGO! It stepped up to another RPM level with a prop that it really wasn't pulling very well and was rock solid consistent. It still wasn't perfect because the motor was now running stone cold with all the air, but it was another awesome find and once he gets the cooling airflow and water restriction working together it will be a huge improvement over how the boat has been!

When I get my sport 20 finished I want my motor thinking it is still in the rigger with no cowling! Holes and ducting baby!!!

GQ

 

[Jerry Dunlap]

Here's what I did to the cowling to allow more air to the engine. The second photo is the cowling before taking the Dremel to it.

I plan to test on Saturday.

JD

 

[Glenn Quarles]

Here's what I did to the cowling to allow more air to the engine. The second photo is the cowling before taking the Dremel to it.

I plan to test on Saturday.

JD

Looks like that will do it!! Great job! Let me know how it goes Saturday.

GQ

 

[Olly]

Getting air to the motor is not my problem as I noted in my previous post, I have been running it without the cowl.

I have now changed the motor and will be hoping for more fun than misery this weekend.

Olly

 

[P THOMAS]

Here's what I did to the cowling to allow more air to the engine. The second photo is the cowling before taking the Dremel to it.

I plan to test on Saturday.

JD

Another thing about closed in cowls and exhaust pipes, you have to be sure the tail pipes are not leaking exhaust into the hull, this exhaust will run back thru the carb and cause a bad running motor.

 

[Tim Kish]

Olly tested with the cowl off, no change.

 

[Andy Brown]

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...

"Steve Wood prepped the motor,..."

Did Steve have any ideas?

Olly, Send the engine to Elias as he offered to test it in his boat. Elias just won the Nitro shootout with his 45 DD. It works flawlessly in his boat. That test would eliminate any kind of boat related issue.

P.S. Elias is a perfectionist. He will take very good care with your engine.

 

[steve wood]

I never saw the motor. i think I installed a velocity stack on his carb, that was sent to me by Ron Jefferson. that's it

 

[Ron Jefferson]

I never saw the motor. i think I installed a velocity stack on his carb, that was sent to me by Ron Jefferson. that's it

Yes, that's correct Steve. I sent Olly's carb with mine for mods. The engine was never sent to you.

Ron

 

[Terry Keeley]

I never saw the motor. i think I installed a velocity stack on his carb, that was sent to me by Ron Jefferson. that's it

Yes, that's correct Steve. I sent Olly's carb with mine for mods. The engine was never sent to you.

Ron

Sorry, thought you had seen it...

 

[Elias Vazquez]

Are we still talking about the motor that Tim found the issue where the crank does not have the correct size in the pto output shaft to properly seal the crankcase? or is this a different motor?

 

[Andy Brown]

Are we still talking about the motor that Tim found the issue where the crank does not have the correct size in the pto output shaft to properly seal the crankcase? or is this a different motor?

Are we still talking about the motor that Tim found the issue where the crank does not have the correct size in the pto output shaft to properly seal the crankcase? or is this a different motor?

Elias, We are talking about Olly's engine that apparently does have the correct shaft, if I'm not mistaken. Also sounds like the engine is stock.

 

[Andy Brown]

Wow! I just wrote a long explanation of Olly's problem per my study of the video. And it disappeared.

So now here is my short answer.

#1 Bigger prop.

#2 Bigger stinger diameter. Re: my discussion about stinger diameters and spraybars.

Both need to be done to correct the issue with Olly's boat. Not one or the other. BOTH!

I think there is nothing wrong with the engine at all! It cackles rich and sounds strong when it gets a load and cleans up.

 

[dion smith]

Bugger!! I'm sure it would have been a great read too

 

[Elias Vazquez]

Olly, you have a pm

 

[Marty Davis]

I agree 100% with Andy, and it will get better and better as it breaks in more and more. The newest head button and the revised nitro pipe are also a part of the successful combination.

 

[Jeff Schindler]

8-16-2014. Mendota, IL

Phil Thomas Sport 40 w/ Novarossi .46 wrap around. 60% fuel Prather 235

Boat took off gurgling good and rich. By the second mill lap it was running like it did in practice, about 55 mph. Boat started bogging down so I went into survival mode, 1/3 throttle and full rich. The boat started speeding up at this throttle setting until it reached full speed. I tried to milk the throttle, surging up and down for 2 laps. I stayed inside to let the leaders by and popped a bouy. This is the Eureka moment.... The cowl came off the boat. The boat ran better the next lap, starting to go rich again. I leaned the needle back down and it ran great, just bogging the corners a bit. I leaned it some more and it was back to full song. That pipe is getting too hot.

I have an inboard video showing the spray hitting the pipe and you would not believe how fast the water boils off.

 

[Andy Brown]

8-16-2014. Mendota, IL

Phil Thomas Sport 40 w/ Novarossi .46 wrap around. 60% fuel Prather 235

Boat took off gurgling good and rich. By the second mill lap it was running like it did in practice, about 55 mph. Boat started bogging down so I went into survival mode, 1/3 throttle and full rich. The boat started speeding up at this throttle setting until it reached full speed. I tried to milk the throttle, surging up and down for 2 laps. I stayed inside to let the leaders by and popped a bouy. This is the Eureka moment.... The cowl came off the boat. The boat ran better the next lap, starting to go rich again. I leaned the needle back down and it ran great, just bogging the corners a bit. I leaned it some more and it was back to full song. That pipe is getting too hot.

I have an inboard video showing the spray hitting the pipe and you would not believe how fast the water boils off.

Very good Jeff! I'm not surprised considering how hot the pipe gets in a rigger. This engine has little experience in the sport hydros. Probably going to need a water cooled pipe like the guys in Europe use in their FSR-V's. Water cooled header at minimum.

 

[Rudy Formanek]

Sport 40 II with Picco 45 Short stroke:

After a couple seasons of tearing my hair out. I finally went to a complete one piece pipe that I made a cup adapter front to fit the Picco. I then found I was having problems with the silicone piece in the cup. I was making my own out of clear silicone hose and grinding a "D" shape on the OD with a Dremel sanding drum with the silicone piece slipped on a aluminum tube chucked in the lathe. I found the black Picco stock rubbers worked better than clear silicone, don't know why. Putting some water cooling on the cup at the engine helped those last a lot longer. People told me not to watercool the pipe, especially near the engine. I now will always water cool my sport 40 pipes. Your mileage may vary.

 

[Roy McManus]

One hell of a write up , enjoyed all 239 post , good job guys!