[Amps] Warm Coax question

[Doc Johnson]

I am not sure where to ask this question but it kinda fits in this forum. I 
have a 2 meter repeater system. It consists of multiple RX feeding a voting 
system then feeding a 375 watt Micor xmitter. The xmitter is located on top 
of a building approx 60' away from the antenna (DB224 4 bay dipole) which 
is fed with 7/8" foam hardline. I am using a 2' jumper to connect the 
xmitter to the antenna  which has been 9913 and rg213. The jumper gets 
quite warm to the point it is uncomfortable to touch. Another confusing 
issue is I tune the amp up with a Bird watt meter and when I remove the 
watt meter the plate current lowers by about 50-75 mills.  Any input? SWR 
is 1.3.:1 which seems a touch high for an antenna that is tuned for the 
amateur band.