My Mayhem .26 engine is slightly problematic?

[emu67]

I have a Mayhem with the .26 engine in it. I think it has about 3 gallones through it or so. The engine starts up fine, tunes well, runs greats, and idles well. After about 5 minutes of running the buggy around, I notice that the idle has changed when I bring it in to temp check it. In fact the idle will get so low that the engine will just die? What's happening?? First the idle is good; I run it around and bring it in then the idle is slow enough to stall the engine so I need to adjust the idle at the transmitter.

Also, even after adjusting the idle at the transmitter, the engine seems to load up anyway and dies after 10 secs or so?

Anybody see this behaviour in their .25 sportwerks motor; any ideas how to make the idle more reliable.

 

[ZANDOR]

Well It doesn't sound like an air leak.
How is the pinch? 3 gallons can wear a mill like that one out in a hurry.Under heavy use....

How are the temps? are they staying steady

 

[emu67]

The pinch on the engine seems fine and the mill seems to run at a consistent 200 to 210 F. I have noticed that even though the mill is running at 210 F, the carb will appear to vapor lock if it stalls and it will be difficult to restart again. Could a clogged air filter cause this behaviour or a leaky gas tank?

 

[J_Bone]

What plug you using? I know mine didn't like Mcoy 8's or 9's. Only Mccoy 59's seemed to run good in it.

 

[vbgagnon]

a leaky tank could definatly cause that. How is your glow plug?

 

[Rotorxhead7]

what the hell is a pinch?

 

[vbgagnon]

pinch is another word for compression, usually when the engine is cold.

 

[GGASMAN]

i run the RB 6 in mine and it runs great.

 

[SuperMaxx83]

i have 2 sportwerks .26 and i have had the same problem anad for me it was me low end was to FAT and after a good amount of tunning it doesn't do it anymore and i run temp like 220 to 245 and goooobbbbsss of power

 

[emu67]

My plug is ok, I think. The element still looks good and it's straight and all. I'm using the 59's because I had used the other ones and the engine didn't like those at all. Are there other plugs that hold their heat better?

 

[vbgagnon]

MC 59 is a hot plug. It should do you fine. I say reset your needles to stock settings and retune from there.

 

[emu67]

So, you run yours at 220 to 245? Maybe I'm running my fat since I'm getting up to 210 at the end of a tank. Ok, so I'll need to retune the low end needle and I'll put in the fresh 59 to make sure things are good.

Thanks!

 

[XXChAoTiCXX]

I was thinking the same thing as I read through this thread, until I got to your last post, emu67. I hope you have figured out your problem already, and I would agree that you want to be running around 220-240 at race temps, but at an empty tank your temps will go up naturally due to leaning out (I know you know this already)..

 

[XXChAoTiCXX]

when you figure it out, post it here so we all get edjumacated from it too...

 

[emu67]

Well - I did reset the needles and began tuning from there. When the engine is cold, everything seems to tune just fine. After the engine gets up to temp, then things went south. The engine just dies at idle. Doesn't matter if you fiddle with the low end needle either; it acts the same. Also, it hard to start when it's warm but very easy when cool (as in not run yet). It's not vapor locked either when it's hard to start. So...no such luck.

I wonder if it's time to get a new piston and sleeve? Does anyone have tell tale signs of this and does a problematic idle count as one of those signs?

 

[BUGNOUT]

Well - I did reset the needles and began tuning from there. When the engine is cold, everything seems to tune just fine. After the engine gets up to temp, then things went south. The engine just dies at idle. Doesn't matter if you fiddle with the low end needle either; it acts the same. Also, it hard to start when it's warm but very easy when cool (as in not run yet). It's not vapor locked either when it's hard to start. So...no such luck.

I wonder if it's time to get a new piston and sleeve? Does anyone have tell tale signs of this and does a problematic idle count as one of those signs?

My friend had the same exact symptoms with his SW 26, those are signs that your engine has lost its compression. It will start easily when cold because thats when the engine has its most compression(pinch), as it heats its up an engine loses some of its compression, in my friends case after it was warmed up I was able to spin the flywheel with one finger. Even when his engine was cold there was still hardly any compression. After your engine has warmed up and then stalls check the pinch then.

 

[rcnutcase]

Emu67,
Your engine has lost it's pinch! My motor does the exact same thing as yours. Starts and runs great cold, but when it's warm it runs weird and won't start until its cold again. I'm ordering a new motor, after the four gallons mine has seen I'm sure the rest of the motor is not far behind my piston and sleeve.

Bill

 

[emu67]

Yeah, I figured the pinch was gone. Cost of a new piston and sleeve is about $50 so that's not so bad. Anyway, I took my engine apart the other day and looked at the sleeve. I figured it's gone anyway so I did some "backyard re-pinching" of the sleeve. Took a pair of large pliers and put pressure near the top of the sleeve. I did this 4 times, rotating the sleeve after bearing down on the pliers. Guess what? It worked! I started the buggy last night, warmed it up to operating temperature. It runs great; idles great. I wonder how long last??

Oh - I wouldn't recommend to anyone that they do this but it worked for me. It was dumb to pinch a sleeve with a pair of large pliers!