Sunday I was testing my GX-5, with 6.5 venturi. The engine was great for our track. Very good run time and bottom end.

The GX-5 is very smooth to drive, its a great engine to have.

Im running Byron 20% nitro 12 % oil, with 086 Dynamite pipe and NR #6 plug.

Have fun and keep tunning

ALG

Right this engine is giving me a right headache...........

So todays problem......as follows

When I pre-heat my engine I cant prime the fuel to the carb, it kind of bubbles up to the carb and then flows back to the tank.

When the engine is cold I can blow into the pressure line and get a nice solid flow of fuel to the carb??

I am running in a GO GX5R and it needs pre-heating as the pinch is mental, have had it running though this only happened today have put about 2 tanks through it so far

OK - Don't go too crazy when you heat the engine. Concentrate the heat on the sides of the cylinder where the sleeve and piston are located. What is happening is your heating the carb area too much. The carb is so hot that when you blow fuel into it, the fuel is boiling as soon as it hits the carb and because of the expansion in the fuel when it boils, the pressure this creates is pushing the fuel in the line back into the tank. Commonly called "vapour lock".

Heat the cylinder area for 20 - 30 sec. Undo the glow plug 1/2 a turn. This will ease the compression and make the motor easy to turn over.
Make sure you heat the motor then try and start it straight away. Don't let it cool, and make sure your glow starter is fully charged or has fresh batteries.
When the motor starts, immediatly tighten the glow plug. The motor will run a little erratic while the plug is loose, but as soon as you nip it up things will return to a nice idle.
By the sound of the pinch test you have your botton needle (LSN) too lean, and maybe your idle a little low too.
You want to have the engine reving up only slightly (correct idle gap), and running on for 5 - 7 seconds (ballpark LSN setting).
Increase the idle 1/4 turn, and turn the LSN 1/4 - 1/2 turn out and try starting again. It may be your motor is starving for fuel, combined with the vapour lock, which is why it won't start. Good starting settings for needles is both needles flush, then go in 1/4 turn on the LSN.
Honestly, the GX motors are not that tight (compared to the old Pro Series). If everything is set right, with a little pre heating it should just fire straight up.

You need to quit worrying about the fine tuning bullsh_t with
the carb needles. Set both needles a hair in from flush, fire
it up, throw it on the ground and burn some fuel through it.
With only two tanks burned through it, you should be running
the settings rich anyways. Don't even think about a race tune
until you have burned over a gallon of fuel and most of the tight
pinch is gone. If you rush and do your break-in improperly your
just going to end up with more headaches in the long run.

hey guys . just a stupid question. I got a GO 5 port. i got no time for racing so i am getting into the monster truck bashing thing. My question is , can i some how convert my go 5 port with a spin or pull start. i have a savage and it wont use a bump start.

yes, look up massive mods. they have a roto start kit.

How can I tell if I have a long or short LSN?
Got my engine from Taiwan.
And are Go gonna make Onroad engines as well?

Frode

Hi Frode,

Read page 676 ad 677 of this thread for details.
Basicaly if the needle is still in the receiver jet a WOT you have the long LSN. If the needle comes out of the receiver jet at WOT (even by a small amount) you have the short needle LSN. See pics below for actual physical difference. Long needle on the left, short needle on the right.

Short LSN tunes like most other carbs. The long LSN tunes a little different.
See the Tech Tips page on my web site www.go-racing.co.nz for tuning details on the long needle carb.

If your motor came from Taiwan it should have the factory standard long needle.

Go had a .12 motor in the wings last year. I am assuming it is still under development. Mark at Massive Mods will be able to shed more light on that.

Ok, thanks. Partnumber is 21-2003. The text is in chinese, so not so helpful :-)

OK. 21-2003 is the long needle. The short needle is 21-2003A.
Follow the tuning guide mentioned above for the long needle and you will be sweet.

NB - the picture of the short needle above taken from the A-Main web site shows the part number as 21-2003 which is incorrect.

Thanks :-)

Just got back from Mexico on vacation, had a few pm's in my box about motors, aside from racing this weekend I should anwer any pm's or e-mails. If I didn't get back to you resend it.

Rex

any news on making a modified .25 go engine?

the current .25 from go is strong at the bottom but lack the speed for a truggy

I have modded a .25 and it was wicked....if i remember correct it showed a massive increase in top end over stock when it was dyno tested....

can anyone point me in right dirction to find out who the go engine dealer is for the usa .. my hobby shop is tring to find out since i quess the last ones
may have quit ... thanks