Fuel oct, ethenol, break-in, etc.

[Corso]

New guy here. I have a new Rampage MT V3 that will be delivered tomorrow. I am not new to 2-stroke or R/C, but I am new to 2-stroke R/C.


I have been doing some reading and watching of videos to gain a little info before my truck arrives. One thing I haven't found any definitive info on is what octane rating to use? In my Stihl chainsaw and trimmer, and my Redmax blower, I run 89oct per my dealers advice. Would this hold true for the 32cc motor in the Rampage? Is 87 ok....is 93 better....?


Next, I have seen some comments about no ethenol. Now, we all know ethenol is evil, so is this just advice to try not to use it, or is it mandatory that NO fuel with ethenol be used? I live in CT and I can't say I know of any places that sell ethenol-free fuel.


Lastly, break-in... I have read about the rather lengthy break-in process. Now, is it ok to drive the truck during the break-in process, or should the truck be up on blocks or a stand and run with the wheels off the ground? Sounds like a silly question, maybe a combination of both?


I appreciate any insight folks could share. Thanks.

 

[RampageHopUps]

The lower octane will be good for your stock 32cc. Ethenol will also be OK.

Look for the OBR tuning and break-in video, it's the best way. The stock motor is very forgiving, so the break-in isn't that critical.

 

[phreerider]

on the ethanol, go "marine grade" gasoline(as it is etoh free if available) 87-93 octane is fine. break-in is easy , at least 4 good heat cycles about 10min each with cool down in between, easy on throttle no full bore runs. gradually add more throttle range each subsequent couple of sessions...then focus on tune. have fun!

 

[Corso]

Thanks, fellas. Truck came today....wow, no matter how many pictures you look at or videos you watch, nothing does justice like seeing it in person. Massive!

I should have waited to ask my octane question because it is stated right in the manual, 90-93 is recommended. I'm sure 87 & 89 is just fine too.

Thanks again.

 

[Corso]

Had absolutely beautiful weather today here in CT, so I decided to get outside and fire up the truck for the first time. I watched the OBR video and followed their tips on needle position for carb settings. I turned both high and low needle all the way in, then backed out the high needle 1.5 turns, and the low 1.25 turns.

*I will mention that, according to the manual, they recommend NOT playing with the high/low settings until after break-in. They say that they are set and tested at the factory and are positioned in the ideal position for break-in. They then go on to say that after break-in you can adjust the high and low needles.

I premixed my fuel at 25:1 using Stihl HP Ultra full synthetic oil and 93oct gas. I put fuel in the tank, primed the bulb, set the choke, and gave the pull-start a tug. Took about 3-4 yanks to pull adequate fuel into the carb. Two more and it popped like it wanted to fire, just like my chainsaw. I turned off the choke, and on the second pull it roared to life.

She idled perfectly, just a tad high. I dialed back the idle screw about a full turn and it was idling great. I let it idle for 15 mins., then killed it and let it cool for a full 15 mins. I went back to start it, no choke, and it started on first pull! I let it idle for another 15mins. I did a total of four 15min idle/15min cool cycles.

Tomorrow my plan is to begin driving it to continue the break-in process. So far, so good!

 

[RampageHopUps]

Sounds like a good start. No need for 93 octane. 87 actually works better for stock engines.

 

[ika]

Can you explane why 87 is better than 93 for stock ???

 

[RampageHopUps]

There is an explanation in here somewhere. I will look.

 

[Corso]

Hmmm, went out this morning to start truck and no-can-do...? Didn't touch any of the settings from yesterday. I definitely flooded it while attempting. Pulled plug and did a de-flood procedure. I checked to see if plug was good. Spark seems real weak, as in, barely visable, but I'm not sure if that is normal or not for the factory plug?

Letting truck sit now. Any ideas? She started/ran like a top yesterday out of the box. Today, nothing.....

 

[designed2survive]

Hmmm, went out this morning to start truck and no-can-do...? Didn't touch any of the settings from yesterday. I definitely flooded it while attempting. Pulled plug and did a de-flood procedure. I checked to see if plug was good. Spark seems real weak, as in, barely visable, but I'm not sure if that is normal or not for the factory plug?Letting truck sit now. Any ideas? She started/ran like a top yesterday out of the box. Today, nothing.....

- Unflood it

- put a new spark plug in

- start it

 

[Corso]

Update: As I suspected... I ran down to Autozone and picked up a NGK CMR7H plug. Got back, put it in, no choke, started 2nd pull. Don't know why stock plug worked great yesterday but gave me issues today? Oh well, all good now.

I did one more 15min idle/cool cycle, then ran over to the local high school and ran it gently in the parking lot. She ran awesome. Can't wait to get through break-in. Can't wait to put a good pipe on it either.

 

[designed2survive]

4 15mins idle will foul the plug when at factory settings. That's what happened. Rarely do you go through break in without it happening due to the rich setting.

 

[Corso]

Well, I got bit by the mod bug today. Ordered DDM Dominator pipe, HPI Baja air filter, and SCNC belt-drive kit.

 

[Corso]

Need a little help. I went out to do another break-in run and had an issue. Truck started effortlessly and idled perfect. I ran it gently, rolling on and and off the throttle, just taking it easy. I ran it for exactly 9 minutes (I was timing it) and out of nowhere it just stalled. I tried restarting it with no luck. Not wanting to flood it, I quit trying. I let it rest for 15mins, wanted to do a cool-down anyway, and again, couldn't get it started.

Questions.... Is this the fuel vent/starvation issue I read about? Is it possible for a plug to foul mid-run (I am still running 25:1)? Thoughts?

Thanks.

 

[Corso]

Disregard.... All good!

 

[Corso]

Anyone stay with the 25:1 fuel ratio after break-in period is complete? Truck seems to be running great on 25:1 and I kind of like having the extra lubrication. Any issue with sticking to 25:1?

Thanks

 

[RampageHopUps]

As long as you punch it once in a while you will be OK. Too much oil fouls plugs sometimes.

 

[Ice_2k]

Anyone stay with the 25:1 fuel ratio after break-in period is complete? Truck seems to be running great on 25:1 and I kind of like having the extra lubrication. Any issue with sticking to 25:1?Thanks

Afaik 25:1 is the correct mix (OBR recommend 28:1 for their engines). For the breakin I used 20:1

 

[ika]

A sugegest always to stay with 25:1. Low oil reduces compression ,increases wear and heat. You wouldn't see any noticeable gain with low oil ratio.

 

[Corso]

Afaik 25:1 is the correct mix (OBR recommend 28:1 for their engines). For the breakin I used 20:1

Correct, OBR recommends 28. My manual suggests 25 for break-in, then 30 thereafter. I suspect depending on when when a manual was written may yield different recommended ratios. Lol