squarecrumpets

COPS is terrible. There is a way to get the same engines brand new w/o COPS but I take it most won't want to replace it just for this reason.

My spring broke on its own last week. I've been using a box starter so the COPS cord hasn't been pulled for weeks. While the engine was idling I heard a loud snap and the cord just came out. Had to snip it off with a pair of cutters. I've replaced the whole COPS unit with a new one as I happen to have a spare.

These are 2/3 AF size. Unfortunately you can’t get much larger capacities (the highest I’m aware off is 1,600 mAh) however your run times don’t sound right. What make and model is the vehicle you’re using to them in?? Sent from my iPhone using Tapatalk Pro

No there's a screw that adjusts the spring tension. It's a centrifugal gear shift device that shifts at a certain RPM when the centrifugal force overcomes the spring's force.

Hello all, This is no longer available. Thanks.

Thanks I have checked and been checking all those things. They all seem to be spot on. Today I tried to tune only the HSN based on temperature. I brought 2 of those IR gauges to cross check accuracy. Interestingly even at factory HSN settings on 25% fuel the temp goes up to over 110 Deg which is out of range. Should i try a cooler plug? I’ve been running medium and the weather has been quite hot. EDIT: The newer version of the manual says the normal range is Thanks. Sent from my iPhone using Tapatalk Pro

Hi again, I have received and set up the starter box which works like a charm and is very helpful because my engine stalled numerous times today. The idle was too low at first. I also started using the IR head temp gauge and found the engine temps after high speed runs to be way too high at about 120 degrees C. The spec for this engine says the max should be 107. I then started richening the HSN but it didn't help much and the engine stalled after high speed runs a few times. I then returned the HSN to factory settings and leaned it by 1/4 turn and the temps came down but was still quite high so I richened it by 1/8 turn. i.e. it is now running 1/8 turn leaner than the factory default settings. The temps are now around 100 degrees C but the acceleration is noticeably worse than before. Am I stuck with this config due to the temps? btw the above was with 25% Optimax. After that I switched to 20% Optimax and the temps came down to about 93 degrees C but the performance is much worse now. As usual any advise would be greatly appreciated. Thank you.

Hi, I've decided to take the buggy out for a quick spin as the starter box would only arrive tomorrow or the day after. So I've richened the HSN by 1/8 and leaned the LSN by 1/2. After doing so, I've noticed the overrun is a lot shorter (approx 1 - 1.5 seconds). The bogging down after sitting idle is also a lot less. I think the LSN needs to be leaned some more. Unfortunately I ran out of fuel before I could record a nice video. I forgot to take the head temp gauge with me. I'll check the temps next time. The hoses to the fuel filter are very tight so no leakages there. I don't use after-run oil as I tend to start the engine up every 2 - 3 days at the moment. Hopefully things will improve. I hope I'm on the right trajectory with this one.... Cheers.

Ahh I heard your message come in but thought I'd read it after placing the order. I've just ordered the Fastrax one. The FLIR stuff are a bit fragile. This one is much easier to use and quicker to position. It's definitely a good investment.

I pinch the tube right at the top of the fuel tank so I don't burn myself yeah it's non scientific. Will ignore that for now. Will try richening the HSN and leaning the LSN as you've suggested. Yes Optifuel 25%. Thanks for pointing out that the smoke can be misleading with this one. I wasn't aware of that. I've also got a bottle of Optifuel 20% which gives less acceleration. I've been using a FLIR IR camera to check the temps. I'll look for one of those gauges that you've suggested as they aren't too expensive.

Hi, Yes I have the engine run on problem. I used to think my throttle was stuck open but now I'm 100% sure it is running on for a second or two. The guys over here seem to think it's caused by the LSN being too lean: https://forums.traxxas.com/showthread.php?265996-Solved-Engine-Run-On-Overrun-problem-when-decelerating however the issues we were discussing above seem to indicate the LSN is too rich. Honestly I've been getting conflicting observations and am not sure whether the LSN is too lean or rich at the moment.

Thanks. I'll give that a go, preferably once the SMD starter box arrives as I always have issues starting this engine. It's difficult to prime etc. Anyway just a thought, I did the pinch test and the engine revs up in about 1 second and stalls in about 4 seconds. Sometimes it takes a second longer. This tells me that it's too lean but the starting procedure tells me that it's too rich. This is what confuses me and I hope you could shed some thoughts on this. Thanks again.

Thanks, I'll try that. At the moment I have to increase the idle by 1.5 turns to start the engine and back it down again after it's started. Is this normal or is my LSN too rich?

Hello, Actually the issue isn't really covered in the video that you would have watched. Here's a very exaggerated example of it, but quite often it just revs up slowly and throws a lot of smoke rather than bog down like in this video. If you would fast forward to 20 seconds into the video, that's the issue that I'm referring to. Thanks in advance once again.

Hello, Thank you for confirming that my engine’s tunes pretty well. I have tried leaning the HSN but it causes the engine to stall at top speed and thus I’ve richened it again. Been playing around with the LSN too and will need to experiment a little more. I still believe it’s too rich but not that far off so I’ll take your advice. The only issue left that annoys me is if I leave it idling for a while then when I hit WOT it will bog down at the start as it purges a lot of white smoke before revving up. This doesn’t happen if I leave it idle for less than 10 seconds. Is this normal? Thanks. Yes I’ve found myself a used SMD starter box like the one Naresh suggested. I’ve also ordered 2 x 6 Sub-C battery packs to power it. At the moment I have 4 spare buggy wheels in the car boot that I use as a platform for resting the buggy on while starting and warming up. The starter box will take that place now. I’m reluctant to power it with LiPos due to the fact it’ll be left in the boot most of the time. I’ll check the video that you’ve shared out. In the meantime it would be great to hear your thoughts on the issue with bogging after idle that I’ve mentioned above. Thanks in advance. Sent from my iPhone using Tapatalk Pro