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Compression?

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George#1

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:confused: I read on another post where I person had only 95# on one cylinder and was told that it would affect the carbs. I'm wanting to know if this true? If I done my compression check right I would only have a average of around 95#s on all my cylinders. My motor surges when going to wot, could this be my problem?
 
Yeh, it starts ok, idle is still a little rough. I just rebuilt the carbs. I've done a lot to this motor but can't get it to stop surging. It's a j150plees
 
Is the surge a slow type surge such as one would encounter if the engine was slowly running out of fuel... then slowly picked up fuel from another source..... OR is it a immediately sudden surge such as yanking a spark plug wire off, then after a short time, putting the plug wire back on?
 
idle is still a little rough[/QUOTE ] It may not be running on all cylinders. Check for loud snapping blue spark at the end of each plug wire. While idling you can pull one plug wire at a time w/insulated pliers...the ones that make no change to engine idle when pulled are questionable. The surging is usually a fuel delivery issue...what happens when you choke it? Describe how you cleaned the carbs...long soak, blow w/comp.air. How did you set the mixtures?
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Ok tested the spark, one cylinder not firing. Don't have the proper test equipment to test the power pack. I don't think it's the power pack, since I put a new one on in the spring. So I'm going to change the ignition coil with one that is working. To make sure it is just a coil. Would one cylinder give me that much surge? I'm thinking maybe the other coils maybe breaking down, runs ok on idle but starts to surge at about 1/3 throttle. I have tried pumping the primer bulb at that time but did nothing to help. I've change fuel line, & primer bulb, new fuel pump kit in the vro2 pump, new kit in the vapor bowl, new kits in the carbs, new spark plugs, new wires. Nothing has fixed the problem, I must say when I put the plugs & wires on it did run a little faster before it would start surging. I also found the head was leaking water on the port side up around the thermostat, the top cylinder is also the one that doesn't fire. And one other problem I have for is that my kill switch doesn't seem to be working either, it's in the keyed switch, with the lanyard off it will still start & run.
 
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addressed the kill switch problem in you other entry before i saw this one..here is my take on the running problem...on any problem you need to start with 3 things ...good compression should be verified first....good spark 2nd...fresh known good fuel...after that you have a decision to make...is it fuel or fire related?....you know you have one cylinder not firing....fix that....always fix what you see broke..
 
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