96 Challenger cuts in and out from 5500 to 4500 rpms

[936brian]

Its a 787 that i just rebuilt the topend. It ran fine for the break-in period then started having problems. It would start to plain out then when I hit about 5500 rpms it would bog down to 4500 rpms and surge back to 5500 and back and forth. I already cleaned all the gas filters and the fuel valve(which was pretty clogged. At first I thought it was the plugs fouling out and would clean them and it would usually run good for 5 mins then start messing up again. I have checked the rectifier yet but i will soon. Any Ideas?

 

[936brian]

I tested the rectifier and it showed 14.0 volts

 

[seadoodude1]

Give you had gunk in fuel system, I suspect residual debris has collected in the internal carb filters. Certainly worth checking before you destroy another top end with a lean burn. On my ski, after replacing selector valve and fuel lines, mine stopped up again so I just added another inline filter right before carbs, something easier to change. No problems sense.

 

[936brian]

Thanks, the inline filter is a good idea. I did it on my HX. I've already cleaned out the filters in the carbs once and I just took another look and they are good. I just blew out all the fuel lines with an air compressor and very little debris came out. Also I don't have the notorious grey lines.

 

[936brian]

I noticed that i'm missing the gasket on the PTO carb (part #270 500 103). Would this cause the problem