1999 force 120 runs on 2 cylinders

[mikeb07087]

HELP!!!!
I have a 99 force 120 hp that I can't seem to get to run right.
It seems to only run on two cylinders-- usually the lower two
Idle is rough with a lot of sputtering

typically covering the upper carb has no effect on performance, covering the lower carb will result in a stall. removing the plug wires from lower two cylinders will run OK on the upper two cylinders, but still has rough idle.

Adjusting the carbs has no effect on idle speed or engine performance(other than stalling)

Timing is correct,
compression is good on all four cylinders
CDI packs check out per Clymer, and are all uniform
All four plugs are sparking
Carbs have been cleaned out about 5 times (just to be sure) New needles

new trigger coil (solved previous problems of runaway speed and kill switch not working-- scary!)
New stator--(old one was fine, clymer has the wrong specs for this unit)
(both stators (new and old) put out about 80 DVA volts to ground GW-gnd & WG-gnd)
new plugs
fuel recovery check valves are OK (2 replaced)

I am at my wits end-- got spark, got fuel, but not working right

 

[pnwboat]

Re: 1999 force 120 runs on 2 cylinders

Have you checked the reed valves which are mounted under the carbs? I hear that the later model Force engines have a tendency to break or crack reed valve petals. Broken, cracked or leaking reed valve will affect performance, idle, stalling etc.

 

[mikeb07087]

Re: 1999 force 120 runs on 2 cylinders

Reed valves looked OK some slight gaps but seem within tolerance, and I get good compression

 

[pnwboat]

Re: 1999 force 120 runs on 2 cylinders

You certainly have replaced a lot of components! Isn't the stator supposed to put out a minimum of 180 volts? You said 80 volts, or is that a typo?

 

[mikeb07087]

Re: 1999 force 120 runs on 2 cylinders

Depends on how you measure get about 80 v line to ground about 160 line to line. Still not quite in spec, but its a brand new stator (battery voltage is good)

The Clymer and Seloc books have incorrect information on the stator resistance range, as both my old and brand new stators have similar resistances, but are slightly out of the "good" range per the books.

The slight voltage descrapancy and the slightly out of spec resistance caused me to replace the stator. No improvement after replacement