Engine issues

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Bicketybam

Bicketybam

Member
Messages
28
i am having an issue with a Dynamite Mach 2 .28 “Big Red” engine. After I run it for about 1/2 a tank or so it will suddenly stall. There will be no fuel in the fuel line. Even priming it at this point is almost impossible (by blocking the exhaust port and cranking it over). I have to pull the fuel line off the exhaust and blow into it to get fuel back into the carb. And sometimes I will see it run right back to the tank before I can reconnect the fuel line to the exhaust. I’ve checked the tank for leaks and there aren’t any. What else should I be looking at? BTW, this engine is not on my Savage. It’s on a Losi Muggy. Thanks!
 
Bicketybam said:
i am having an issue with a Dynamite Mach 2 .28 “Big Red” engine.
Click to expand...

Have you checked the exhaust coupler
Or the header gasket . Or your FUEL LINE from tank to Carb ?
 
What are your engine temps? Pretty sure that engine runs an alloy carb without an insulator, so once it's hot, the carb is hot too. A hot carb will boil fuel and send it back up the line.

Doesn't explain why it flames out though. The fuel/air coming in usually keeps the carb cool enough to do it's job, but once the engine stops, the carb wicks in a lot of heat from the engine almost instantly and causes hydrolock until it cools.
 
olds97_lss said:
What are your engine temps? Pretty sure that engine runs an alloy carb without an insulator, so once it's hot, the carb is hot too. A hot carb will boil fuel and send it back up the line.

Doesn't explain why it flames out though. The fuel/air coming in usually keeps the carb cool enough to do it's job, but once the engine stops, the carb wicks in a lot of heat from the engine almost instantly and causes hydrolock until it cools.
Click to expand...

The hottest I've seen it is 210. Usually I'm sitting between 190 and 200.
 
Well, water boils at 212. So a normal engine at running temp of 225-250 will boil the fuel out of the carb.

The flame out is what's weird. How much fuel do you have through the engine? More than 5 gallons? I've only had/been around a handful of dynamite/losi engines. They tend to get fussy around the 7-8 gallon point even if they were well taken care of. Compression gets low in them due to wear on the piston/sleeve and you get blow by.
 
olds97_lss said:
Well, water boils at 212. So a normal engine at running temp of 225-250 will boil the fuel out of the carb.

The flame out is what's weird. How much fuel do you have through the engine? More than 5 gallons? I've only had/been around a handful of dynamite/losi engines. They tend to get fussy around the 7-8 gallon point even if they were well taken care of. Compression gets low in them due to wear on the piston/sleeve and you get blow by.
Click to expand...

Ok. I changed all the fuel lines and so far the issue is gone. Has stalled and when I kill the engine while hot I can start it back up. When I went to pull the old line off the fuel filter it snapped and left a piece on the neck. I'm guessing the leak was there.

The engine is only a month old. I have a about 1.5 gallons through it. I did f@ck up the break I'm procedure so I am sure the engine is not operating as well as it could be. It had been a long time since I ran nitros and o dropped the ball. I'll be in the market for a piston and sleeve at some point. I'm happy with the engine. The original Mach 427 was awesome. It was just done. That one had probably 10 gallons through it and then it sat for 10 years.

I am into my Arrma electrics now but I can't seem to let go of the nitro. The sound. The smell. I just dig it. And the Muggy is a fantastic truck. It reminds me of the Arrma Kraton. It's actually a better built Kraton. I'm never giving it up.
 
Bicketybam said:
I am into my Arrma electrics now but I can't seem to let go of the nitro. The sound. The smell. I just dig it. And the Muggy is a fantastic truck. It reminds me of the Arrma Kraton. It's actually a better built Kraton. I'm never giving it up.
Click to expand...

I recently got my first arrma as well, an outcast. My toy truck fleet is heavy on the electric side now. I ran nitro for 18 years. When I got my first electric, I had 5 nitro's. That was 18 months ago. I now have 3 nitros and 5 electric. 7 electric if you count the micro's.

I doubt I'll ever bash nitros nearly as much as I used to, but I know what you get out of them used and my 3 that I still have are so built up, that I just can't bring myself to selling them for pennies on the dollar. I ran a nitro twice this year... I've run a brushless truck almost every weekend since March. Turns out, nitro or electric, I'm just not a fan of being out in the cold anymore. That was why I got into electric in the first place, to bash in the snow without fighting with tune.
 
Bicketybam said:
Ok. I changed all the fuel lines and so far the issue is gone. Has stalled and when I kill the engine while hot I can start it back up. When I went to pull the old line off the fuel filter it snapped and left a piece on the neck. .
Click to expand...

Glad to hear you found it.
I try and follow the KISS theory , Keep It Simple Stupid *. I don't look for big problems first , I look for the small ones .
* ( and in no way am I saying you're stupid ) = disclaimer so Virgilbigfish doesn't get upset. :argh:
 
ELWOOD said:
Glad to hear you found it.
I try and follow the KISS theory , Keep It Simple Stupid *. I don't look for big problems first , I look for the small ones .
* ( and in no way am I saying you're stupid ) = disclaimer so Virgilbigfish doesn't get upset. :argh:
Click to expand...

Elwood, please don't use the yellow color for the font anymore please. It's way to hard to read on my phone.

Bickety, glad you got the problem sorted out.
 
Bicketybam said:
Ok. I changed all the fuel lines and so far the issue is gone. Has stalled and when I kill the engine while hot I can start it back up. When I went to pull the old line off the fuel filter it snapped and left a piece on the neck. I'm guessing the leak was there.

The engine is only a month old. I have a about 1.5 gallons through it. I did f@ck up the break I'm procedure so I am sure the engine is not operating as well as it could be. It had been a long time since I ran nitros and o dropped the ball. I'll be in the market for a piston and sleeve at some point. I'm happy with the engine. The original Mach 427 was awesome. It was just done. That one had probably 10 gallons through it and then it sat for 10 years.

I am into my Arrma electrics now but I can't seem to let go of the nitro. The sound. The smell. I just dig it. And the Muggy is a fantastic truck. It reminds me of the Arrma Kraton. It's actually a better built Kraton. I'm never giving it up.
Click to expand...



This may sound funny to some people but iv had that problem with a couple of my tanks and it turned out that I could not blow hard enough the creat the same pressure as the pipe pulse the exhaust is hotter then what I could breath so I cleaned the tank really well put some red food die in with wetter and used a bike pump with a ball nozzle and plugged the line going to the carb and found the little hair line crack. That a microscope could not find also don't pump in to much air.
 
Savagedad3 said:
This may sound funny to some people but iv had that problem with a couple of my tanks and it turned out that I could not blow hard enough the creat the same pressure as the pipe pulse the exhaust is hotter then what I could breath so I cleaned the tank really well put some red food die in with wetter and used a bike pump with a ball nozzle and plugged the line going to the carb and found the little hair line crack. That a microscope could not find also don't pump in to much air.
Click to expand...

That's not a bad idea.I will keep that in mind for the future.
 
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