I have a 1987 Winner Escape with a 1986 model year 5.7 liter 4V motor, here my problems;
1) Runs at 180 degrees and upto 190 degrees if run WOT (4500 rpm w/ 17 pitch prop) for a few minutes .
I have fix and tried the following;
New thermosat (OMC 160 degree), new gauge and sensor veriftied temp was correct with Infra Red heat gun.
New raw water pump and housing verified flow to motor and back flushed from Tstat housing back through water pump to make sure the there was not a clog at the oil cooler. Installed clear hose section to watch flow while at speed and line is full no air bubbles. Check inlet on stern drive and all clear, I can watch the tsat housing with a heat gun and the tsat open at 160 then just climbs to 180 while idling at dock just stays there maybe 190 once in a while running hard ???
2) Engine runs rough at idle and surges while crusing on plane (3000-3200 rpm) boat feels like your triming it up and down even though your not ??
I have fixed and tried the following
New plugs twice/plug wires/ new cap & Rotor/ PO converted to electronic no points, rebuilt the carburator (Rochester Q Jet) had it ultra sonic clean at shop. New exhaut and elbow gaskets, set timing .
A couple of weeks ago it was real bad and would die / load up after running on plane then slowing to idle found that a new distrubter cap had corrosion in it, too to best shop/ Marina around and all that was found replaced cap and run as discribed above. Check compression all cyclinders 145-150 psi except # 5 was 135 psi. I also pluged all plug wire one at a time while running at 1000 rpm while in gear tied at dock each cyclinder would drop then you could hear it pick right back up ( keep thinking I'm dropping a cyclinder ) so I'm lost ??? Please help ! PS this boat was owed the last 15 years by two older gentlemen and not use at all, the local marina always winterized it and it just needed some TLC but this has me stumped ! Also the Valve cover breather have quite alot of moisture come out of them.
1) Runs at 180 degrees and upto 190 degrees if run WOT (4500 rpm w/ 17 pitch prop) for a few minutes .
I have fix and tried the following;
New thermosat (OMC 160 degree), new gauge and sensor veriftied temp was correct with Infra Red heat gun.
New raw water pump and housing verified flow to motor and back flushed from Tstat housing back through water pump to make sure the there was not a clog at the oil cooler. Installed clear hose section to watch flow while at speed and line is full no air bubbles. Check inlet on stern drive and all clear, I can watch the tsat housing with a heat gun and the tsat open at 160 then just climbs to 180 while idling at dock just stays there maybe 190 once in a while running hard ???
2) Engine runs rough at idle and surges while crusing on plane (3000-3200 rpm) boat feels like your triming it up and down even though your not ??
I have fixed and tried the following
New plugs twice/plug wires/ new cap & Rotor/ PO converted to electronic no points, rebuilt the carburator (Rochester Q Jet) had it ultra sonic clean at shop. New exhaut and elbow gaskets, set timing .
A couple of weeks ago it was real bad and would die / load up after running on plane then slowing to idle found that a new distrubter cap had corrosion in it, too to best shop/ Marina around and all that was found replaced cap and run as discribed above. Check compression all cyclinders 145-150 psi except # 5 was 135 psi. I also pluged all plug wire one at a time while running at 1000 rpm while in gear tied at dock each cyclinder would drop then you could hear it pick right back up ( keep thinking I'm dropping a cyclinder ) so I'm lost ??? Please help ! PS this boat was owed the last 15 years by two older gentlemen and not use at all, the local marina always winterized it and it just needed some TLC but this has me stumped ! Also the Valve cover breather have quite alot of moisture come out of them.
