Fuel problems this year had me troubleshooting the engine. Hopefully I have solved the fuel issues (at least for this year). Pulling the spark plug wires at idle and in neutral showed variation between cylinders. The engine becomes very rough when the #2 or #4 wire is pulled but little change in engine sound is noted with the #1 or # 3 wires removed. Pulling the spark plug wires while in-gear and at medium throttle results in a large loss of power (runs very rough and almost stalls) with either the #2 or #4 wire removed, a very slight power loss with #1 wire removed and almost no change with the #3 wire removed.
The results above caused me to run a compression test. I did test compression in earlier years with a borrowed tester. The data are below. The values are an average of at least two readings. The second values are with two teaspoons of 30wt oil added. The 2005 & 2007 testing done with open choke, full throttle, and all plugs removed
2000 #1) 108/- ; #2) 109/- ; #3) 99/-; #4) 107/- (not sure I tested correctly this year)
2005 #1) 90/117; #2) 100/112; #3) 90/120; #4) 107/-
2007 #1) 83/110; #2) 100/-; #3) 67/92; #4) 106/-
I did the one-quart of MMO added to oil supply procedure and ran the engine for about five hours, mostly at fast idle or at low-medium throttle under load. I noted no change when doing the spark wire removal test again. Changed the oil back to all 30wt.
The engine is a 1977 V-drive and has never had the head off or valves adjusted. I installed FCW in 2005 after one year in brackish water (now in Rock Hall, MD) - before that time the boat was kept in fresh water at the head of the Chesapeake Bay. The engine temperature runs at 150-175F. The engine uses some oil, at most, a quart per 30-40 hours, and there is some bypass haze/odor in the cabin after a long motor. I see almost no noticeable smoke coming out the exhaust.
Obviously, the compression in two cylinders as gotten worst. How do I proceed from here?
If a mechanic needs to remove the engine from its cave for the repair, (not a simple job in this boat), should I have the engine overhauled at the same time? Cost: ring and/or valve job vs. complete overhaul? In other words, how do you know _when_ (if) the engine needs a complete overhaul? – What symptoms do I look for?
OR simply - IT’S TIME for an overhaul – my best guesstimate is about 1200 hours on this 30-year-old engine.
Rod
C&C 33-1
The results above caused me to run a compression test. I did test compression in earlier years with a borrowed tester. The data are below. The values are an average of at least two readings. The second values are with two teaspoons of 30wt oil added. The 2005 & 2007 testing done with open choke, full throttle, and all plugs removed
2000 #1) 108/- ; #2) 109/- ; #3) 99/-; #4) 107/- (not sure I tested correctly this year)
2005 #1) 90/117; #2) 100/112; #3) 90/120; #4) 107/-
2007 #1) 83/110; #2) 100/-; #3) 67/92; #4) 106/-
I did the one-quart of MMO added to oil supply procedure and ran the engine for about five hours, mostly at fast idle or at low-medium throttle under load. I noted no change when doing the spark wire removal test again. Changed the oil back to all 30wt.
The engine is a 1977 V-drive and has never had the head off or valves adjusted. I installed FCW in 2005 after one year in brackish water (now in Rock Hall, MD) - before that time the boat was kept in fresh water at the head of the Chesapeake Bay. The engine temperature runs at 150-175F. The engine uses some oil, at most, a quart per 30-40 hours, and there is some bypass haze/odor in the cabin after a long motor. I see almost no noticeable smoke coming out the exhaust.
Obviously, the compression in two cylinders as gotten worst. How do I proceed from here?
If a mechanic needs to remove the engine from its cave for the repair, (not a simple job in this boat), should I have the engine overhauled at the same time? Cost: ring and/or valve job vs. complete overhaul? In other words, how do you know _when_ (if) the engine needs a complete overhaul? – What symptoms do I look for?
OR simply - IT’S TIME for an overhaul – my best guesstimate is about 1200 hours on this 30-year-old engine.
Rod
C&C 33-1
Comment