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Old 11-27-2010, 11:30 AM   #1
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Default Jato 2.5 engine question

Hello,
I currently have a Jato 2.5 that idles well and accelerates well. The problem that I have is that the engine cut out when I rapidly squeeze the accelerator trigger on the remote. I have all of the carb setting at factory. Can anyone please tell me what is going on and how to correct the problem.

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Old 11-27-2010, 02:06 PM   #2
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I guess what you're saying is it accelerates well as long as t=you don't squeeze the trigger too fast? My guess is its rich if you have it at factory setting, thats purposely made to be rich. Are you sure the LSN is set properly, it sounds like the LSN may be set rich. Its supposed to be adj to where its even with the inner part of the carb barrel.

If the LSN is set properly, it could still be rich. Lean it 1 or 2 hours (think clockface) and see if it gets better. The needles in these are sensitive so I wouldn't be making 1/4t type changes cause you'll miss the sweet spot where you want/need to be. If it shows signs of getting better, keep adjusting a small amount at a time. If it shows no signs of getting better, try leaning the HSN in the same manner.
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Old 11-27-2010, 02:18 PM   #3
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Thank you for the information. I will give it a try.
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Old 11-28-2010, 01:21 PM   #4
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Default Fuel cut-off test

I did the fuel cut-off test from the manual and I ended up having to richen the LSN. Know the car does not stall when I rapidly accelerate. What I notice now is that it is stalling when I am at full throtle going down the road. I am currently at 4 turns on the HSN. Could this problem be that I am too rich at the high end. My temp was around 160 F, but it was only around 40 F outside.

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Old 11-28-2010, 02:36 PM   #5
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Yes, you're too prob rich.

You also need to wrap the cooling head and get temps up over 200F. The piston slamming into the pinch wears the pinch and puts a lot of stress on the rod and crank pin. Engine needs to get to at least 200F so watch and if its not getting hot enough, wrap cooling head with a sock or if that doesn't raise it higher enough, alum foil.
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Old 11-28-2010, 06:51 PM   #6
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Default pinch ?

Thanks for your help. What do you mean by "pinch"?
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Old 11-28-2010, 07:03 PM   #7
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The cylinder (or sleeve) the piston runs in is tapered, its smaller at the top than at the bottom. At the top is the only place where the piston actually seals the cylinder. This tight zone at the top of the cylinder is called the pinch.

This part of the cylinder is actually smaller than the od of the piston at room temp, but when both get to its normal operating temp, both expand such that the piston OD matches the ID of the cylinder at the top of the cylinder (top of piston's stroke) to provide a seal for combustion.
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Old 11-29-2010, 08:53 AM   #8
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Thank you very much for all of the information. I hope to get it tuned this weekend.
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