#1
IP: 74.103.75.17
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#3 & #4 Not Firing
Coming off winterization #3 & #4 cyclinders are not firing, Engine starts fine (2 or 3 turns) but only cyclinders #1 & #2 are firing.
Cycl #1 - Compression 90#, Plug a little sooty Cycl #2 - Compression 90#, Plug good Cycl #3 - Compression 70#, Plug wet Cycl #4 - Compression 90#, Plug wet Confirmed cyclinders 3 & 4 are getting spark with induction timing light and also pulling plugs and grounding them to the block. Confirmed plugs are good by switching them between cyclinders. Cannot tell what the wetness is on plugs. No obvious water in cyclinders (ie no water pumping when engine is cranked with the plugs out and no water showing in oil) but have not run the engine much because of the problem. I tried filling the cyclinders with Marvel Mystery Oil in case something was stuck but this has not made any difference. I don't know where to go next except to pull the head. Any other suggestions? Thanks for your help. |
#2
IP: 24.224.206.117
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Harry,
a. Was the water intake turned off for starting. b. Is it raw water cooled? Try leaving the intake shut and start the engine. Let it run for about 45 seconds then open the water. If it bogs down then: a. Intake Manifold rupture....my first inclination because so many people use the plumber antifreeze....nothing but auto antifreeze 50/50 mix in mine. Plumbers antifreeze is not worth a fiddlers in an iron block and mechanic don't mind pushing it..if there is a weak/rusted/plastic area he will have work in the spring. You can check the manifold by holding a finger over the fitting at one end and blowing into the other. Remove plugs. If there is a leak you will hear air in the spark plug holes. b. Head gasket... That would be a start anyway. Happy 4th.
__________________
Mo "Odyssey" 1976 C&C 30 MKI The pessimist complains about the wind. The optimist expects it to change. The realist adjusts the sails. ...Sir William Arthur Ward. |
#3
IP: 74.103.75.17
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Maurice,
Thanks for the feedback. Raw water cooled. Always start the engine with the water off and problem occurs immediately. Used straight -50F marine antifreeze to winterize. Antifreeze put in with thermostat removed and bypass hose clamped so it should have done a pretty good job of protecting the engine. Good thought on the presurizing the manifold...I'll give it a try. Thanks, Harry |
#4
IP: 24.224.206.117
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Harry,
Try cleaning the plugs and running with the water off for a short period. That will tell you allot. When the water is turned on, note if she starts to miss immediately. Then you know water is on those plugs. Water on a plug looks like a bubble on it...it beads. Gas has a uniform wet look. All the best.
__________________
Mo "Odyssey" 1976 C&C 30 MKI The pessimist complains about the wind. The optimist expects it to change. The realist adjusts the sails. ...Sir William Arthur Ward. |
#5
IP: 12.69.97.2
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Are the spark plug wires in correct firing order, 1-2-4-3?
DanR '77 C&C 29 |
#6
IP: 155.104.37.18
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Yes, they are in the correct order and the plugs and wires both have less than 10 hours on them. Electronic ignition. Looks like I am getting good spark to the cyclinders.
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#7
IP: 74.103.75.17
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Maurice,
The weekend is approaching and it is time to get serious about getting the A4running. I like your idea of pressurizing the manifold to see if there is a leak into the cyclinder. Any feel on how much pressure and if I can pressurize it too high? I was going to use an air compressor but I am concerned about too much pressure blowing out the gasket. |
#8
IP: 107.0.6.244
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The specification is that the manifold should hold 20 psi.
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#9
IP: 74.107.82.144
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Broken Valve Spring
Removed manifold and head and found a broken spring on the #3 exhaust valve. I have a Catalina 27 and access to the valves is not the best so I am going to cut an access panel through the wall in the port quarterberth. However, even with this better access replacing the spring is going to be a chore. I would like to just replace the broken one but am interested in the experience of others whether one broken spring is an anomoly or the start of more broken springs (ie - can I get away with just replacing the one or should I replace all of them)?
Thanks, Harry |
#10
IP: 74.110.198.83
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I am an advocate of "while you're in there and have it all opened up, replace them all." If one broke, it seems to me that's as sign of age and fatigue (after this weekend, I'm experiencing that myself). Seems to me if one broke, the others are probably pretty worn also. Since you're going to go through all that trouble to gain access to that side of the engine, it would seem a lot of effort to just replace the one that broke and leave all those old, worn springs in there.
But that's just me; can't say that is "the right" answer, based on hard data or anything.
__________________
- Bill T. - Richmond, VA Relentless pursuer of lost causes |
#11
IP: 173.166.26.241
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I have to agree with Bill. In addition, remember the springs themselves are cheap; it is your labor that is costly. Do the job once.
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