Request for help - PB Nova 21 engine

[junka]

Hi,

I'm hoping to resurrect the some r/c items here and have a query..

I've acquired an old PB Nova & as such everything works.

I'm having problems with the engine however.

It will start (sometimes straight away) and stall, or start and try rev flat out then stall or my personal fav - start and die when I touch the throttle.

I've attempted to adjust the fuel settings in an attempt to get sustained running but to no avail. (made notes and returned to original positions)

I've no manuals at all & from what was said it seems likely all the fuel settings have been played with - so I'm hoping some of you kind folks have a record of what the factory/recommended settings should be and can help me?

To preempt (some of) the expected questions: glow plug is fine (orange/orange white), fuel is good, fuel lines not blocked (checked & cleaned), air intake filter is ok. I disconnected the rear brake so there's little drag on the engine, just in case.

On occasion there is fuel sprayed up against air filter, not sure if that's usual & could be down to the over priming. Exhaust is reasonably free of unused fuel.

If there's an online version of the manual I can't find it btw :/

Thanks in advance to any suggestions

J.

[tt-01owner]

if your engine stalls when you give it some throtle it means your needles are not lean enough.

lean all needles untill it doesnt stall, during idle and under full throtle.

or rich it untill it doesnt stall, during idle and under full throtle

lean means more air, you can do this by turning the needle clockwise

rich means more fuel, you can do this by turning the needle counter clockwise

[fastboy]

remove the air filter and check that the air gap looking down the carb body is about 1-1.5mm when the carb slider is fully closed.use the idle stop screw to make sure that you cannot close the carb more than this.

you shouldnt really need to give the engine any throttle when starting if its set correctly.

make sure fuel is in the tank,empty the main fuel line to the carb,reconnect,attach a piece of fuel tubing to the fuel tank if it has a nipple to do so(usually goes to exhaust to keep fuel pressure up,most modern types do)open the carb wide open,blow down the tubing that is connected to the top of the tank so as to blow fuel into the carb under pressure,if fuel does not flow freely then the carbs man needle is too lean and needs opening up a little(anti clockwise),once this is done,close the carb and repeat after emptying the line of fuel.now fuel should flow when the carb is closed but not quite as free as the fully open carb,adjust to suit,hopefully engine should fire now.

remember it shouldnt be able to run flat out straight away,it should burble a little when cold and take a bit of coaxing to get upto good rpm,it takes about 2-3 mns to get the engine upto optimum temp,you cant tune the engine when its cold,it has to be hot.

[junka]

Cheers

Have batteries on charge and will try give that all a go tomorrow if I can. I'd be rightly stuck without you folks!

Carb slide is about 5mm out currently btw - so that's some indication

J.

[WillyChang]

PB Nova kit doesn't come with an engine from the factory, so the car's manual is of no use to you.

Make sure you are using Fresh Fuel and a known-good glowplug, before you start doing anything else. Make sure the fuel lines aren't cracked and leaking in air either.

[Ferris]

hay just running through a purchase of a Nova (overseas so I should get it in a few weeks), and it has a full PB manual with it (full?!!) Whilst the PB manual will have zero engine help, I will pdf you a copy as soon as I get it. Maybe nice/usefull?

Mark F

quote:Originally posted by junka

Hi,

I'm hoping to resurrect the some r/c items here and have a query..

I've acquired an old PB Nova & as such everything works.

I'm having problems with the engine however.

It will start (sometimes straight away) and stall, or start and try rev flat out then stall or my personal fav - start and die when I touch the throttle.

I've attempted to adjust the fuel settings in an attempt to get sustained running but to no avail. (made notes and returned to original positions)

I've no manuals at all & from what was said it seems likely all the fuel settings have been played with - so I'm hoping some of you kind folks have a record of what the factory/recommended settings should be and can help me?

To preempt (some of) the expected questions: glow plug is fine (orange/orange white), fuel is good, fuel lines not blocked (checked & cleaned), air intake filter is ok. I disconnected the rear brake so there's little drag on the engine, just in case.

On occasion there is fuel sprayed up against air filter, not sure if that's usual & could be down to the over priming. Exhaust is reasonably free of unused fuel.

If there's an online version of the manual I can't find it btw :/

Thanks in advance to any suggestions

J.

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[junka]

Originally posted by Ferris

Whilst the PB manual will have zero engine help, I will pdf you a copy as soon as I get it. Maybe nice/usefull?

Hey

Yeah anything will help me get it all back to working right - appreciate anything

Got new fuel and glowplug & made a note of current settings.

Will give it a go later today and see where I get to.

The engine's a Picco marked 3.5 btw

J.

[WillyChang]

Picco with black head and razor-sharp fins??

(owww... from memory)

[junka]

quote:Originally posted by WillyChang

Picco with black head and razor-sharp fins??

(owww... from memory)

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heh not quite.. I really will have to sort out pictures.

lost a fin long time ago in a fancy backflip over a manhole cover

[junka]

hey, good news..

had the car running yesterday and today.

settings seemed so far out, I'm not surprised I was having problems.

it's not perfect yet, but starts quickly from cold and flies along nicely - getting it stalling sometimes when I stop (fuel seems ok, no air etc).

thx for the advice etc

[fastboy]

if its stalling when you brake then could be 2 things

the idle screw needs screwing in a bit more to stop the carb closing too much and starving the engine of fuel,or the clutch shoes are dragging on the clutch bell(new springs needed) or even the clutch bearings could be ******ed.

dave

[junka]

quote:Originally posted by fastboy

if its stalling when you brake then could be 2 things

the idle screw needs screwing in a bit more to stop the carb closing too much and starving the engine of fuel,or the clutch shoes are dragging on the clutch bell(new springs needed) or even the clutch bearings could be ******ed.

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Hmm.. I tried screwing in the idle screw a bit. The revs starting to go up and it holds a little better, but still stalls easily enough.

Am I meant to set the brakes to be slightly on when the throttle sticks neutral, or are the cars generally meant to roll forward a little if 'unattended' ?

The clutch - took apart, cleaned and a new rubber o-ring installed of same size (that's all that stops the clutch 'plates' from engaging)

Have stripped, cleaned and reasembled the rear section including the brake section which now works a bit better. Not put it back together yet.

Figured I'd clean it up a bit better now that the car seems 'usable'.

The carb slide seems to stick a little, almost like it's worn and now it's been cleaned up, there are areas in use that weren't used before (esp at full throttle - it would stick without the servo pushing it back). I was careful to put the screws and servo mechanism back the way they were to avoid additional confusion when initially trying to restart/adjust the engine settings, so I'll have to revisit this.

Good thoughts, thanks

J.

[fastboy]

is it stalling when you brake or does it stall basically when its sat on tickover?

my car is set so that there is no brakes on when its on tickover,i can push the car backwards with no clutch drag.

it may be the bottom end needle is either too lean or too rich,try a 1/8th either way,remember it takes about 15-20 secs to clear a loaded up crankcase of fuel,make the adjustment and rev it a few times,put on floor and let tickover for 10 secs then nail it,if it smokes real bad its too rich,if its too lean it will hesitate or no smoke visible.

if when you put it on the floor the revs drop off slowly then dies its probably too rich on the bottom needle

[Virus]

quote:Originally posted by junka

quote:Originally posted by fastboy

if its stalling when you brake then could be 2 things

the idle screw needs screwing in a bit more to stop the carb closing too much and starving the engine of fuel,or the clutch shoes are dragging on the clutch bell(new springs needed) or even the clutch bearings could be ******ed.

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Hmm.. I tried screwing in the idle screw a bit. The revs starting to go up and it holds a little better, but still stalls easily enough.

Am I meant to set the brakes to be slightly on when the throttle sticks neutral, or are the cars generally meant to roll forward a little if 'unattended' ?

The clutch - took apart, cleaned and a new rubber o-ring installed of same size (that's all that stops the clutch 'plates' from engaging)

Have stripped, cleaned and reasembled the rear section including the brake section which now works a bit better. Not put it back together yet.

Figured I'd clean it up a bit better now that the car seems 'usable'.

The carb slide seems to stick a little, almost like it's worn and now it's been cleaned up, there are areas in use that weren't used before (esp at full throttle - it would stick without the servo pushing it back). I was careful to put the screws and servo mechanism back the way they were to avoid additional confusion when initially trying to restart/adjust the engine settings, so I'll have to revisit this.

Good thoughts, thanks

J.

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always adjust your hsn (high speed needle) first this is normaly where the fuel goes into the engine via the carb this adjusts the fuel flow into the carb and be ready to mix with the air, this needle give your car/truck its top speed, your truck/car will always smoke when at full throttle if not you wil have a problem with heat and this will damage your engine resulting in new piston and liner

to find the best hsn setting start your car upand run it for a few mins to build up engine temp and settle the fuel flow then turn the hsn needle 1/8th clockwise do this while the car is running on idle then slowly pull of until full speed. keep adjusting this needle until no diffrence is notice in speed gained. but make sure you always see a plume of blue is smoke.

the lsn needle is the low speed needle hence lsn. ok to adjust this you have to be careful with car still adjust the lsn 1/8th turn clock wise (this would normaly be flush with the carb body so your finger runs smooth over the screw and its not raised.)and now take a run you will notice an improvement in how fast the car starts of from a stand still. now return car/truck and adjust again, take car on second run, wow you say its good lol, ok now return car and adjust for final time this is where things become slighty hairrasing. if the engine starts to over rev stop engine and adjust the lsn just under 1/8th anticlock wise. still remember at full speed you need a blueish plume of smoke once your car is tune away you go BUT after you have finnish you need to put the hsn &lsn back to factory settings. the reason is that the weather has adverse effects on nitro cars and this will give you the best chance of starting your car in all weather.also in winter you may want to warm up the engine head with a hairdryer to help start the car .

hope this helps you out and explain the way you should tune and run your nitro.

what name fuel do you use would help me help you getting your nitro to run well and last a long time

Virus

[junka]

Fastboy & Virus... outstanding

Be easier to reply to you both in one go methinks..

Last time we met, so to speak, the car would 'generally' idle ok when it was just started. Once I'd run it about a bit (smokes on half+ throttle, spit test good - no proper temp sensor available) it would stall quite easily.

In hindsight, I probably didn't let the car run long enough to adjust between carb settings, so I couldn't be sure if the setting was lean/rich.

The 3 adjusters available to me are: flow adjuster between fuel tank and carb (hsn?), idle screw and fuel/air screw. Not sure where the lsn fits there

To cut a long story short, I had a look at the old fuel that was stored with the car. I thought tho it burned ok, that it might have lost too much nitro to be any good.

However, I filled the tank up and went about starting the engine.

With a small increase in idle speed, the car seems a lot happier to sit idling.

So I think that's the problem - the old fuel (model technics dyna glo 5) runs fine, while the one I was recommended (model tech quikfire 10) provides poor idling due to the relatively small amount of fuel required for it to idle without driving off down the road!

Perhaps the 5 vs 10 fuel should have been an obvious pointer to something I was doing wrong, but I figured an increase in power could only help, so long as it didn't overheat the engine.

Live and learn eh?

So.. there we have it - plug everything in, use old fuel (15 years old, sealed and kept cool and in the dark) and it starts in 30 seconds and runs great!

I owe you all beers/sodas

On a side note, I'm assuming the old JR AM tx/rx set isn't going to cause undue problems - everything 'new' is FM.. right/wrong?

PS that reads like a bunch of pages from random books, I do apologise :/ but it's at least in order

J.

[Virus]

glad all help in the end mate

no you shouldnt have much problems with the JR elecs mate. as with fuel you could try some tornado 16% you can use this in enines up to .18 in size. .21 engines and upwards use a 20%/25% nitro fuel mix. as for a good temp sensor use the spittle test i know it sound disgusting but if it evaps on first contact your engine is running a little lean [].

the lsn yup thats the air fuel mix [] bottom end grunt (acceleration)

the hsn is the tap the fuel arrives at from tank.

little tip turn on electrics,remove air filter, now with the brake fully engaged look down into the carb. the throttle/carb slide inside should be close right down except for a small gap that is 1mm. if not adjust the idle screw untill that gam measure 1mm. turn of electrics replace air filter. prime up and start you should find the car will idle nice and smooth when brake is fully ingaged.

if you change nitro fuel to higher strengh or even just the brand name you will need to retune the whole engine all over again its a pain but worth it. try bryons or tornado mate you will find your engine will be more responsive through the power range []

hope this all helps i have just finnished installing a new nitro engine in my pure ten rally nitro []

Virus

[junka]

quote:Originally posted by Virus

glad all help in the end mate

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too early in the morning for you too?

spittle test is looking good & the slide is open about 1mm as you suggest - so I think that's it sorted.

Once again, cheers for the help and advice, I'd never have got anywhere without it.

Good luck with your own car!

J.

[Delfosse]

Hi Mark,

I think you've got some documents about PB NOVA ( manual and other documents ).

I just bought a PB NOVA and i can't rebuild the front of the car and i think it's not complete.

Can you send me a copy of the documents you've got ? and a picture of your PB NOVA ?

Thanks,

Serge Delfosse

Email : sb127792@skynet.be