won't stay primed

[GulfJasper]

Hi, all. new to nitro. had a friend just give me a redcat shockwave that has a drive line issue but I would like to get it running before I spend any money on parts.
It seems to take a bit longer then I think it should to prime and it will only run for a few seconds and then I have to prime again. if I raise the RPMs I can keep it running if I place my finger over the exauhst outlet every few seconds. fuel lines look good and tight. I don't see anything loose any noticeable bad gaskets. it had been sitting a year or so. the fuel he gave me is that old to. any ideas or suggestions?

 

[D3MON]

Welcome to RCT!
id replace the fuel lines either way as its like a buck a foot and only need like 1.5ft for the entire car, id also check for air leaks in the fuel tank, can submerge in soapy water, while you plug one end and blow into the otehr to see if any bubbles pop up. typically its the fuel cap gasket.
also that fuel is probably toast, if it was stored in a cool, dry, and out of sunlight spot it may be "OK" but id recomend getting new fuel, save the old stuff to clean the engine with though, works really well.

 

[Z.hb71]

Hi, all. new to nitro. had a friend just give me a redcat shockwave that has a drive line issue but I would like to get it running before I spend any money on parts.
It seems to take a bit longer then I think it should to prime and it will only run for a few seconds and then I have to prime again. if I raise the RPMs I can keep it running if I place my finger over the exauhst outlet every few seconds. fuel lines look good and tight. I don't see anything loose any noticeable bad gaskets. it had been sitting a year or so. the fuel he gave me is that old to. any ideas or suggestions?

Looks like it has low compression to me. Becuase these engines fuel pressure so to speak comes off the exhaust fuel line into the tank and the fuel gets pushed into ur engine. Now I'd think if it's not doing that you have low compression, I could be off the mark here but that's my thought

 

[Z.hb71]

B

Welcome to RCT!
id replace the fuel lines either way as its like a buck a foot and only need like 1.5ft for the entire car, id also check for air leaks in the fuel tank, can submerge in soapy water, while you plug one end and blow into the otehr to see if any bubbles pop up. typically its the fuel cap gasket.
also that fuel is probably toast, if it was stored in a cool, dry, and out of sunlight spot it may be "OK" but id recomend getting new fuel, save the old stuff to clean the engine with though, works really well.

BUT first try these things ?

 

[cbaker65]

Hi, all. new to nitro. had a friend just give me a redcat shockwave that has a drive line issue but I would like to get it running before I spend any money on parts.
It seems to take a bit longer then I think it should to prime and it will only run for a few seconds and then I have to prime again. if I raise the RPMs I can keep it running if I place my finger over the exauhst outlet every few seconds. fuel lines look good and tight. I don't see anything loose any noticeable bad gaskets. it had been sitting a year or so. the fuel he gave me is that old to. any ideas or suggestions?

It sounds like an air leak ,make sure that the tank lid seal doesn't leak!....

 

[cbaker65]

Looks like it has low compression to me. Becuase these engines fuel pressure so to speak comes off the exhaust fuel line into the tank and the fuel gets pushed into ur engine. Now I'd think if it's not doing that you have low compression, I could be off the mark here but that's my thought

Your right about that ,the pressure line is crucial to push fuel to the carb ,that being said ,one would have to make sure
that the line is not plugged or restricted!


Some mufflers have the tube that connects at the bottom of the muffler ,that is not good ,there will be loss of pressure
right there do to fuel & residue build up!
Always make sure that you change the outlet to the top side of the muffler ,or change pipes!

Some don't have a nipple for the tube to fit on ,an the tube just fits in a hole in the muffler ,with that , make
sure the tube doesn't bottom out!

Cut the tube in an angle ,that will prevent the tube from bottoming out an restricting the pressure!....

 

[GulfJasper]

Thanks for the replies, I'll check these things when I have a chance. Is there a way to check the compression other then just feel?

 

[cbaker65]

Thanks for the replies, I'll check these things when I have a chance. Is there a way to check the compression other then just feel?

If the buggy sat for a while ,then it should be cleaned!
As fuel sits in the engine ,it will gum up the carb. & fuel tank ,most fuel tanks have an internal
fuel filter ,the tank will need to be cleaned out ,I use hot soapy water an shake the heck out of it ,
then let dry out!
You can turn the fly wheel by hand to check compression ,it should get hard to turn as the piston
goes to the top.
Also ,check the head bolts ,an make sure that they are tight!

 

[olds97_lss]

Thanks for the replies, I'll check these things when I have a chance. Is there a way to check the compression other then just feel?

Take the glow plug out and turn the engine over very slowly. If you feel it tighten/bind a bit as the piston reaches the top of the stroke, it's probably ok. If you don't, then you can take the engine apart and try pushing the piston up in the sleeve by hand. If it reaches the top or comes out of the top with very little force, then it's worn out.

This was after sending them to RayARacing for a mild re-pinch to be done:

 

[D3MON]

i need to send my piston/sleeves to these guys, looks like they do some amazing work.

 

[Daniel J]

Hi, all. new to nitro. had a friend just give me a redcat shockwave that has a drive line issue but I would like to get it running before I spend any money on parts.
It seems to take a bit longer then I think it should to prime and it will only run for a few seconds and then I have to prime again. if I raise the RPMs I can keep it running if I place my finger over the exauhst outlet every few seconds. fuel lines look good and tight. I don't see anything loose any noticeable bad gaskets. it had been sitting a year or so. the fuel he gave me is that old to. any ideas or suggestions?

It’s usually a blocked carb. You need to clean it out.

 

[GulfJasper]

Hey, finally had some time to play with this thing again. I cleaned all the old fuel out and gave her some new, and she fired right off.
I also figured out why my buddy hadn't been using it. I've got something busted in the rear diff. the socket where the right rear axle slides in the diff housing is falling out.

 

[cbaker65]

Hey, finally had some time to play with this thing again. I cleaned all the old fuel out and gave her some new, and she fired right off.
I also figured out why my buddy hadn't been using it. I've got something busted in the rear diff. the socket where the right rear axle slides in the diff housing is falling out.

I don't know about that car ,sometimes those cups are locked down with a set screw or what is called
a grub screw ,check for that!