Engine Issues

[Cy25]

I am having some troubles with tuning my rampage. Its a HY 30.5cc engine with a Z-RC intake and a .012 copper gasket. I have gotten about 6 tanks of a fuel threw the motor. (Would be more but these things seem to run forever on a tank of gas.) Still running the stock spark plug (INK CMR5H) at this time. The motor break in seems to be going just fine. It has great mid range and great throttle response. However, it doesn't want to open up on top end and lack of bottom end/launch power IMO. I have run power saws almost my whole life and I feel that it should have more snap on low end even for only being 30.5cc. I have tried tuning the carb in but I think I am hitting a brick wall. It will run good for a few minutes then it will stall out like it gets too hot. I have to hold the throttle wide open and pull quite a few times for it to fire and stay running. Once I get it to fire I can run it up to top end and clean it out its fine for a few more minutes. I took a picture of this plug after I pulled it thinking its fouled and put a new one in.(attached) The brand new plug (NGK CMR5H) seems to start easier but still isn't tuning in and running like I think it should. I haven't taken a temp gun to the jug or exhaust yet to get a temp but definitely seems hot. So my questions to everyone on here are:


1. Am I running it too lean or rich?


2. What does a typical plug look like on these when its running correct? ( I was told once they should be a golden brown color)


3. Is my problem High or Low end tuning or both?


4. Am I running a too hot or cold of plug? (I live in central pa and temps have been between 70-85 Degrees and 70%+ Humidity)


5. Is this a problem with the stock carb that comes with these things I have been hearing about?


6. Am I still in the break in phase to the point where I should just run it when I can until it shows that it is broke in and the performance will show itself? (Most saws I ran required 8 tanks of fuel threw them before tuning)


Thanks ahead of time and will be awaiting your answers and/or possible solutions....


~Cy

 

[Deluge]

Looks a little rich. The plug should be a brown paper bag color when it's tuned correctly. Also, you want to read the plug after you do a high speed run and kill it before it idles, otherwise you'll get an inaccurate reading. My break in process lasts no longer than a tank, I just do a warm up run and gun it from there. At 6 tanks, you're well passed the break in phase.

Also, if you're still running the stock exhaust can, performance will be sub par.

 

[454chad]

you need to vent your fuel tank too you may be vapor locking

 

[Cy25]

Oh sorry...I forgot to mention that the tank is already vented. I did that after my first tank and it was soaking my air cleaner with fuel.

Deluge - So I should make a full out pass, kill it before it can idle down, and then pull the plug and check color? Just making sure I am understanding you correctly. Looks like i'm making a stand to keep the truck in one place. PROJECT!!

 

[GTS 666]

Yep as Deluge advised to check plug is right but from all the posts on this forum I would be looking at putting a walbro carb on to get and keep a good tune. I also tend to believe that keeping it a little rich on the Lsn and leaning out the high helps with my tuning IMO.

 

[alfred e numan]

Yep as Deluge advised to check plug is right but from all the posts on this forum I would be looking at putting a walbro carb on to get and keep a good tune. I also tend to believe that keeping it a little rich on the Lsn and leaning out the high helps with my tuning IMO.

Yea, thats me also. after the engine is heated up, i turn the lsn - find the point of highest rpm-- the sweet spot. but when throttle is applied, it goes lean for a second- This is the idea with me notching the butterfly plates- when a plate is notched over the 3 holes in the carb bore, the lsn has to be opened slightly- Its a real balancing act- I have made inprovements to the off idle resopnse when the idle is mixture is set to its sweet spot- Mikuni- Keihn dirt bike carbs have assorted cutaways on the slides. thats my idea on this WT issue.

 

[alfred e numan]

Yea, thats me also. after the engine is heated up, i turn the lsn - find the point of highest rpm-- the sweet spot. but when throttle is applied, it goes lean for a second- This is the idea with me notching the butterfly plates- when a plate is notched over the 3 holes in the carb bore, the lsn has to be opened slightly- Its a real balancing act- I have made inprovements to the off idle resopnse when the idle is mixture is set to its sweet spot- Mikuni- Keihn dirt bike carbs have assorted cutaways on the slides. thats my idea on this WT issue.

Not trying to steal this thread- The 990 eqippped F-270 responds really well to the butterfly mod- i have correct plug color from idle- to wot. The 2 bolt engines seem to respond not the same- gottaawonder if this has to do with porting- the f-270 has huge transfer ports- i am new to this hobby-little engines- its uncharted waters, thats for certan.

 

[cordy]

The cmr5h is a hot plug ,perhaps you should try a cmr7h plug. Just food for thought.

 

[Cy25]

The cmr5h is a hot plug ,perhaps you should try a cmr7h plug.

I was thinking along the same lines. I did some research and noticed that most power saws run a 7 and i have run the piss out of them on some scorcher days and never had them just shut off because of heat. I do believe I will have to try that as well.

 

[alfred e numan]

CY25? sometimes the fuel filter in the gas tank could be restricting the fuel flow- just a thought--

 

[Cy25]

Yes my nickname is Cy. Kinda awkward after realizing that a type of motors are called CY engines.

I got a day or two off of so i am going to tinker with it and try to get it ready. Got a track day next sunday.