Wanted to know if anyone else has seen this problem and if anyone can help me out.

Engine will only run on 2 cylinders when at 3/4 throttle or above. Anything less than 3/4 throttle, the left cylinder will only run intermittenly or not at all. The engine is just past break-in and has had this problem since we started it for the first time. Figured after break-in and alot of carb tweaking the problem would work its way out.

We installed new plugs and even traded the plug wires (thinking it may be electrical) but it is always the left cylinder. We have tweaked on the carb countless times as well as having other DA users tweak on it with no help. I, just today, went through using the XIPP method on the FG site here with still no improvement.

The temps on the left cylinder barely maintain a warm level while the right cylinder is always hot. (No matter what tweaking we do or even with the plug wires switched.)

We run 94 octane gas with Amsoil 100:1. Broke in on LawnBoy Ashless at 50:1

At full throttle, the engine seems to run fine with awesome vertical but as soon as you come off the throttle, the left cylinder cuts out and is very sluggish.

Any help anyone can give would be quite appreciated.

Seth

I am by far not an expert!!! but it sounds like you have a split reedvalve or one that maybe damaged some how??

Scott

Are you using any sort of ignition cut off system.

Second what is your ignition battery pack like. Try another. I will bet you a cold beer it is electrical.

I once had a cutoff fail on me and I replaced the ignition, I done the bleeding lot. It was a faulty contact in the cutoff and it took me like two months to find the dang thing.

Keep us posted as this is hard to diagnose so share what you find.

Check every connection known to man. Bypass your switch, reg or what ever else you have in that ignition circuit. Just put a good battery direct to the ignition.

What can happen is one plug takes more current to fire the spark than the other. The ignition bleeds down to the weakest one and often wont light the spark hardest to fire. Sounds queer but true.

RCIGN is on this site and a ball of knowledge. If he does not come in here I will PM him for you to get his help.



Kiwi

Thanks for info. No cutoffs other that what came in the ignition. I run a duralite battery and always start over 8 volts even at load. I don't run anything external on the ignition such as tachs, cutoffs or anything that isn't already built into the DA ignition.

I never had one of these bad boys apart. I assume there is only one reedvalve? Could part of it be bad to effect only one cylinder? Clue me in.

You are running a regulator right! or is your ignition LiPo capable. You say DA and I did not know they had a direct Lipo capable ignition.

Kiwi

Is there a regulator between the battery and ignition? I have to ask because you said 8 volts...that will kill the ingition. The DA is only good for 6-7 volts. Plus, check the gap of both plugs and make sure they are the same. I am not expert, either, but I think they need to be the same and .019-.023"

Yep, sorry forgot to mention , but yes, I run the Dura Lite regulator between the battery and the iginition.

Also gapped the plugs at .20 each side before I installed the new plugs. Pulled them out and checked the new plugs after run today and the plug from the left bank was black. The right plug was a light brown color.

Should I send the motor back to DA?

Light brown is lean.

What is the other plug like.

Again I would plug a 4.8 NiMh pack direct into the ignition to try it. The reg could be clapping out due to the feedback from the capacitors in the ignition module. They can deliver tons of amps and current, but give them some stray feedback from a sick capacitor and your sunk.

Kiwi

Originally Posted by Kiwi

Light brown is lean.

What is the other plug like.

Again I would plug a 4.8 NiMh pack direct into the ignition to try it. The reg could be clapping out due to the feedback from the capacitors in the ignition module. They can deliver tons of amps and current, but give them some stray feedback from a sick capacitor and your sunk.

Kiwi

The other plug was black and wet

check to see if your hall sensor has moved. Obiviously one cyl aint got fire. Got fuel, just aint got a spark....

Originally Posted by Toro

check to see if your hall sensor has moved. Obiviously one cyl aint got fire. Got fuel, just aint got a spark....

What is a hall sensor?

The hall sensor is the red sensor on the crankshaft.

It sounds like one cylinder isn't firing properly and the other is having to drag the dead weight of the other along. That explains the uneven heating problems. It's strange that you can swap the plug wires and it doesn't change the problem. This is just an idea, but have you tried a completely different module, switch, battery, and reg? If that doesn't do it, I would just send it in to DA, since their customer service is awesome. They'll take care of you.