Striper56,
I've owned an OX66 250hp for several years now. Sounds like a fuel supply issue. If you haven't replaced your 3 low pressure fuel pumps recently, it is easy to check if they are leaking. You won't know if they are leaking because they are bolted to the manifold and use vacuum and positive pressure from the manifold to operate. The fuel just leaks into the manifold, causing your engine to run rich at idle and starve the engine at higher RPM's. Surging is a classic symptom. The engine will run fine until the vst tank doesn't get enough fuel from the lp pumps. RPM's will rise and fall as the vst tank fills and empties. You may not notice this at higher rpms, except that WOT might be lower than expected.
Simply loosen the two bolts holding each pump to the manifold and squeeze your fuel bulb. Do this with your engine off and cool and check one pump at a time.
If the diaphragm is shot, fuel will dribble from behind the pump. If it leaks replace it, or for that matter, replace all 3 as they are only about $30 each. Don't forget to replace the $3 gasket behind each pumps. You can also rebuild the pumps, but for $30 why bother.
|