Genny starts, runs rough and then cleans up
Wanted to see what others thought. Genny just started acting like this. Fire it up, runs rough for 5-10 min, then cleans up and runs perfect. I have never let the carb sit for more than 1 month...
Forum Discussion
lincster wrote:
It will start hot, but I have to go out and rotate the choke butterfly open and then it fires right up.
What are you rotating,,? are you rotating the bi-metal choke housing..? or pushing on the choke plate itself..?
Genny chokes work a little different then a vehicle choke. Our 5500 has no fast idle, and uses a governor unlike a vehicle choke with a fast idle cam lever. So the vac breaker works a little different...
Our 5500 engine must always run at 2400rpm from start to stop, speed must remain at 2400 engine rpm, to keep the genset @3600rpm=(120v_60hz),thru its pulley/belt overdrive gearing.
So basically no 'fast/slow idle' warm-up period on our 5500. 1 rpm only on our 5500, thats 2400rpm.
The engine governor needs to advance the throttle to let its governor maintain 2400rpm within a second or 2 of start up, cold or hot. So manifold vacuum pulls open the choke valve to prevent overchoking the engine within that first second or 2 of start up.
from 5500 shop manual:
"The vacuum breaker diaphragm must not leak under a vacuum of 30 inches Hg (100 kPa). It should not take a vacuum greater than 2.4 inches Hg (8 kPa) to open the choke fully. At a vacuum of 1 inch Hg (3.2 kPa) the choke plate should be at the angle shown (Figure 8-10). If necessary, bend the link at the point shown, using two pliers."
Linc, not sure if you already changed out the vacuum breaker assembly/diaphragm..? but sure sounds like it needs a double check.
I'd look there again for a leaky rubber vac hose or ripped diaphragm, or faulty linkage..?
