chev1

after breaking the motor in i went and adjusted the carb. there is no power the motor has good throttle response but no top speed , tried to lean car out but no effect



thx
john

Im2lazy

Check that the plug is good. Plugs go bad quickly. Also, when tuning the motor, do not turn the main needle more than an 1/12 of a turn at a time. If you turn the needle something like half a turn, you will surely have trouble figuring out how to tune your motor.

Just some basic advice. If you need further assistance, just post again.

chev1

ipretty much have the tunning down wot there is smoke but there is no speed adjusted the 2 speed just nothing there like something is holding it back but i can push the car freely im using an os a3 glow plug so there should not be a problem and using trinnity monster horsepower 20% fuel iot kinda sounds like an clutch issue

Im2lazy

If you think its the clutch, take the dude apart. HPI's standard 2shoe clutches are not known to last long. If it is the clutch, grab MIP's clutch for HPI vehicles.

Have you physically checked the glow plug? They can last for months, or they could go sour in just one tank... and as for tuning, unless I were someone like Steve Odonnel, I'd have to admit to myself that engine tuning is one hell of an issue... seeing as you must regard the plug, weather, needle settings, clutch settings, head clearance, gear mesh, blah blah blah, and especially the vehicle's performance. There are just so many variables that affect our vehicles' performance that may or may not be considered part of engine tuning.

chev1

just got to take clutch apart and check it . no problems there change the glow plug check for the head to be lose .i retuned the car for an hour trying to get top end performance . just nothing there im at a loss. like theres a throtle stop on this car. it probley something stupid im over looking. need help please

thx
john

Qlone

Maybe there IS a throttle stop on your car . Take off the air filter and see if your carb opens up completely when you open up the throttle. Don't do this with the engine running!

If it does not open up completely, use the endpoint adjustment on your transmitter to adjust this.

dub_set

I hav ethe same issue with mine. I can't get the power from the engine to the transmissinon. I'm going to try new clutch shoes and hopefully that fixes the problem. Good Luck!

brc358

iTrader: (18)

Dont over look the flywheel being loose.
Make sure the flywheel nut is tight.
Otherwise, all of the power is being lost with the flywheel spinning, not getting the power to the clutch

NiTrO BoOsTeR

iTrader: (7)

ditch the A3 plug and go for a number 8, make sure the carb is opening all the way, check for air leaks, make sure the clutch isnt slipping, also is it changing into second if it has a 2 speed if not then buy the 2 speed upgrade

Mitchell

dub_set

My engine is not shifting but it is a two speed It idles good but when you punch the throttle or ease into try to get speed it starts to bog before you get 10ft. i tried the flywheel but it was tight and i tried a set of slutch shoes from my other engine and same thing. Could this be that i have the needles and idle screw all mest up to give a false good idle when the high speed needle is set to low? HSN is 3 turns out.

Thanks for the help guys

NiTrO BoOsTeR

iTrader: (7)

mabey be a stupid question but have u touched the needles, it sounds like u havent tuned it,

how to tune
Low end
count to 10 sec
Hit the throttle
if there is no bogging or lagging then no need to lean it
pinch the fuel line if it is about to die at the count of 3 sec then its perfect
if not the lean it out untill it reaches this stage

High end
count to 15
Hit the Throttle
it sould make 3 noises 1 reving 2 changing and 3 a change in the reving (high pitch)
if doesnt
lean untill it does

with ur 2speed clutch u need to adjust it so it engauges so adjust it accordingly

dub_set

I think i'm going to try this i found it in another thread. Good tuning guide.
I think i have problem number 3(at bottom of the post), on the lean end cause of the false idle.

So yes you are right I think my tuning is off but i was confused cause my idle was good. I'll let you know how it works. Thanks alot

Carburetor Needle balance:

It has come to our attention some racers are making the mistake of setting the idle speed opening to wide [high idle] and setting the bottom end too rich! This will give a false normal idle speed even though the speed is set to high because it "loads up" the engine with excess fuel causing the idle to be lower than set!
The end result is a very unstable idling engine that surges and may cut out as full throttle is applied because the over rich bottom end can disguise a too lean TOP end setting!!!

Let's address this a little more in depth! Idle speed opining set too wide: It is possible too set the idle screw adjustment in to far but yet the idle speed is not high! Even though the air regulation [carb barrel or slide] may be set to a position that would normally equal a vary fast idle, the idle is low because the low speed mixture adjustment is set so rich that the engine loads up with excess fuel and the engine goes into what's commonly called a four cycle idle. One tell tail sign of this is if after reving up the completely warmed up engine it tends to idle fast for a few seconds then drops to lower idle speed.

[Here we go again with the written sound effects ]
Something like da..da..da..da..da..da..da..da then it drops to da da da da [if it were sheet music it would be like dropping from 8 beats per measure to 4
beats per measure]

If you start leaning the bottom end a little at a time [then repeat the reving up and idle test] and it takes longer before the idle drops your going in the right direction! Eventually as you keep leaning the bottom the idle will stay to high, now it is time to lower the idle to were it belongs by re adjusting the idle screw!

CAUTION!!!!

Now that you have the idle set correctly the top end may be too lean!!!
Keep in mind the fuel does not directly enter the cylinder area like a 4 stroke engine, it enters the crankcase area first then is transferred or pumped up to the cylinder area by the piston movement.
Simply put, the crank case volume can hold much more capacity than the cylinder so it takes some time to burn off the residual fuel.

In other words if the bottom end is to rich the engine will be supplied by this residual fuel briefly and depending on the demand you may be actually be experiencing a lean condition on the top end that can range from:
1. Seems to run well but engine life is short
2. Seems to run well but car continues to get hotter the longer you run to the point of overheat!
3. Seems to run ok on the bottom but sputters starves or strains to gain rpm
4. Seems to run ok on the bottom but when I give full throttle it cuts out or stalls
[An overly rich top end can act the same as 3 & 4 but excessive smoke and oil are usually present with a distinct blubbering sound]

NiTrO BoOsTeR

iTrader: (7)

HMM i think that is a pile of rubbish. i have been taught how to tune a proper engine. the way i told u is best way to get the best out of ur engine.

with it does it sort of rev-cut out - rev - cut out or it sort of roaring like reaving very slow.

dub_set

Alright i'll try your way first! I found that it said Ron Paris' guide to tuning but i don't even know who that is so i'll try what you said.

It's a roaring like reaving really slow

dub_set

Hey I got it fixed it was about a full turn rich but thats better than lean.LOL
Thanks for all the help. good tips.