Swift Problems, Please help

[kingeightballz]

I recently picked up a Swift from a friend. He was having some problems with the engine. I Started tinkering with it and this is the deal. It seems to run awesome until it reaches operating temperature, about 1/8 or more tank, then completely cuts out. What is the deal with this. It acts like It is flooding. I am not new to this hobby, and I have tried everything that I can think of with no luck. Can anyone lend some advice??? I have lengthend fuel lines, sealed the carb and back plate with rvt , inspected the piston and sleve, I have even gone as far as to enlarge the outlet and inlet for the pressure line( cause it was having a hard time getting primed, and staying primed) I don't know what to do but throw it in the scrap pile and start with a new .26 . The thing is that this motor only has about 1/2 gallon threw it, and another thing is that it eats glow plugs, alot!!! No matter if it is running super rich or not this does not matter they all turn kinda brown on the coil itself. In order to start after it has died you have to hold wot and pull until you have some nice blisters going on. If you let it cool back off then she'll fire right up with nothing wrong(for the first few minutes). Please help I'm frustrated!!!!!!!!!!!!

Thanx in advance ,
Zach

 

[highflyin]

It sound like it is getting to hot and flaming out.Try to richen it up some.What are you temps?

 

[cvec7]

One problem sounds like your carb. might be clogged. Take apart the whole carb. and clean everything off w/ nitro cleaner or carb cleaner.

 

[kingeightballz]

One problem sounds like your carb. might be clogged. Take apart the whole carb. and clean everything off w/ nitro cleaner or carb cleaner.

What do you think that there is some kinda gunk in the carb?? Would that cause it to crap out after running soooo good for the first few minutes??? As for the temps they never exceed 230-240, and there is always a nice trail of blue smoke accompanied by each accelleration. But just as soon as she does hit the 230-240 temp it just dies. :shrug:

 

[cvec7]

Yea, it's worth a try. I had a engine w/ about a gallon through it, and it would never run right, so I heard that the carb might be the problem, so I took it apart, cleaned it, and it ran like brand new.

 

[CorradoPsi]

what brand fuel and % are you using in it as well? what glow plug? and yes the carb can gum up sometimes or get small particals stuck in it.

 

[kingeightballz]

I am running o'donnel 30%, this is what I always run in bb's, I like the higher nitro content and the higher lubrication content. I have tried O'donnel 99's, mc coy 59's and now I have dropped an extra couple bucks per plug on OS A-5's. I will indeed tear down the carb and clean it up, and see what happens. Any other thoughts, or suggestions???

 

[Nitro_Freak]

i had a similar problem to yours, all it turned out to be was a kinked fuel line.

 

[kingeightballz]

well it's defineitaly not a kinked fuel line, but thanks for the input. I tore down the carb and it looked pretty clean. I went through and cleaned anyways, resealed it to the block and hopefully it will be alright. I think that I will check the seal on the tank also. And check to see if there is anything funny with the exaust gasket, and header to pipe groment. Maybe its got a small rip or something, I am running out of options. and by the way anyone know the factory settings??? i heard that they are like 4 turns out on the high speed and 3 to 3.5 turns out on the low speed, does this sound right??

 

[niggle]

I am running o'donnel 30%, this is what I always run in bb's, I like the higher nitro content and the higher lubrication content. I have tried O'donnel 99's, mc coy 59's and now I have dropped an extra couple bucks per plug on OS A-5's. I will indeed tear down the carb and clean it up, and see what happens. Any other thoughts, or suggestions???

30% is a tad high for the SH engine outta the box. You might want to try an extra shim under the head button to lower the compression. You can run 25% with no extra shims.

 

[kingeightballz]

30% is a tad high for the SH engine outta the box. You might want to try an extra shim under the head button to lower the compression. You can run 25% with no extra shims.

Well it's funny that someone brought that up.... The guy that i picked this up from was running 20% in it and was having the exact same problems. I rebuilt the carb and still the same problems. I am going to tear down the entire engine and see wtf is the problem. :boxing:

 

[kingeightballz]

well I tore it down and it looks like maybe some dirt got in it cause the sleve and piston are not a tight fit. I mean it's like you can see light thru the two. what's wierd is that both surfaces are as smooth as could be with out any scores but like its already worn out after only 1/2 gallon???? what a P.O.S. . So it's kinda like fuel is making it past the piston before it's turn... does that sound possible???

 

[WA2FAST]

Well... although the motor is very difficult to tune (just about anyone that has one can tell you that), you still should not run 30% without shimming the head... 25 seems to be about the sweet spot for it right out of the box. It still seems as though the motor has been run lean if you ask me. The tuning on it is very picky... you have to make sure that you are not leaning the hell out of the top end to compinsate for a rich low end... if that is the case, on your long WOT runs, that piston is smokin' hot and wearing very quickly... that is one thing you have to watch out for. On mine, after about a half tank, it decides to lean itself out on the high end... so I have given into how the motor decides it wants to work and have tuned it after the initial half tank... so for the first 1/2-3/4 of a tank, it runs fat as hell, but afterwards runs perfect... temps are all there, blue smoke is intact from the exhaust, still have great compression after a gallon of fuel (which I should of course) but once you figure out the whacky tune on the motor, you'll be fine.

It just seems that with how this motor likes to run that it's leaning way out like they do... I think it is due to how the carb is designed... seems that it relies on tank pressure to feed the fuel a ton more than other carbs, so once the fuel level drops and tank pressure goes down, it leans way out... which would explain premature wear, burnt out glow plugs, and the motor flaming out.

 

[kingeightballz]

Thanks for the input. ya know that makes sense. the other thing I just found out is that the motor was broke in some kinda goofy way. He fired it up and drove it around until it reached 220, then kill it. then he would go for the second tank and do the same deal, thru the first five tanks. do you think this had anything to do with the premature wear??? I have heard of heat cycling the engine , but maybe not such a good idea with this mother f***er of a motor. It's cool, just buy another wasp, or maybe throw in the cheaper mach .26 . not sure yet

 

[niggle]

I just found out is that the motor was broke in some kinda goofy way. He fired it up and drove it around until it reached 220, then kill it. then he would go for the second tank and do the same deal, thru the first five tanks. do you think this had anything to do with the premature wear??? I have heard of heat cycling the engine ...

That's not as stupid as it sounds and is actually close to the break in method recommended by some of the top engine manufacturers.

A new engine has a very tight piston/sleeve fit when cold and if you run it too cold during break there is a risk that excess piston/sleeve wear will occur. If you bring the engine up to temperature quickly then the sleeve expands and the only real wear that occurs is to knock the high spots off the piston and sleeve mating surfaces which is the whole purpose of break in.

Letting the engine cool allows the sleeve to contract and then you can catch the lesser high spots on the next run, and so on.

You still need to keep it on the rich side to allow the conrod bushings to bed in without damage. RB Concepts recommend running in at WOT on a bench with an aeroplane propeller attached.

 

[WA2FAST]

In the end, it's all up to what the manufacturer says as far as the break in process is concerned. They have reasons for what they recomend for the process since they know the materials and design of the engines. Letting the engine get up to ~200 durring initial break in is a common practice though for sure.

 

[kingeightballz]

thanks for the input from everyone. I got a hyper 8 port with a nova head that is running sweet!!!

 

[WA2FAST]

Good to hear. Good luck with it.