My A4 used to do the exact same thing. What I finally discovered was that the coil (hard mounted to the block) had been slowly failing (running hot) and the decreased cooling at idle was the final straw. If you cannot touch the case of the coil after the engine shuts down (turn off the ignition first) when this happens you might try replacing it. Try feeling if it has cooled down when the engine will restart as well. I ended up isolating (heatwise) the new coil, and of course, it never did it again.
John,
Make sure when you go to get your new coil to tell them you need an internal resistor coil NOT an external. This very important for if you install a external one you will have the same problem unless you install a high wattage resistor to the bulkhead or the engine.
Pat
E29
'73
#224
Holy Guacamole
Davis Modlin Atomic4
Make sure when you go to get your new coil to tell them you need an internal resistor coil NOT an external. This very important for if you install a external one you will have the same problem unless you install a high wattage resistor to the bulkhead or the engine.
Pat
E29
'73
#224
Holy Guacamole
Davis Modlin Atomic4
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windjunkee
Member III
Mike,
You can't have your E-32 back.
Whatever Mike did to our A-4, it worked because it doesn't die when we throttle back, ever. It only still overheats on port tack
Jim McCone
Voice of Reason E-32-2 hull #134
You can't have your E-32 back.
Whatever Mike did to our A-4, it worked because it doesn't die when we throttle back, ever. It only still overheats on port tack
Jim McCone
Voice of Reason E-32-2 hull #134
Last week on the way to Catalina I had the motor on because of a lack of wind.
After A while we put up the jenny lookiung for air and still none.
Opened a few more beers and at some point in time noticed we were zipping along at 7.2 knots in a good breeze. The A4 quit, we thru up the main and blasted over the rest of the way at 8.4 knots.
Amazing what a beer can do
Anyways seem the problem is the coil.
After A while we put up the jenny lookiung for air and still none.
Opened a few more beers and at some point in time noticed we were zipping along at 7.2 knots in a good breeze. The A4 quit, we thru up the main and blasted over the rest of the way at 8.4 knots.
Amazing what a beer can do
Anyways seem the problem is the coil.
windjunkee
Member III
Mike,
We haven't done anything with the exhaust riser yet. We have acid flushed the engine and replaced the water pump and impeller. We thought that might have solved the problem, but it didn't completely solve it. What ended up happening is that we now push more water through the engine, which also created a backflow problem so significant that when we shut the engine off and sailed in anything but the most calm seas, we would have seawater running back through the exhaust and into the engine. Virtually every time we went sailing we wouldn't be able to start the engine on our return and found water in the oil AND carbuerator. Anyway, we fixed that by rigging a drain at the bottom of the muffler and draining the entire exhaust system as soon as we shut the engine off to sail.
However, when we motor for long distances (i.e. up coast to Santa Barbara) the engine still overheats only on port tack and only when the heel angle is plus 5 degrees), but heading up or switching tacks immediately, even if only for a few seconds, solves the problem for at least 1/2 hour.
We're convinced it is haunted. Thats the only possible explanation. However, finding an exorcist who is experienced with A-4 engines is a tall task indeed.
Jim McCone
Voice of Reason E32-2 hull #134
We haven't done anything with the exhaust riser yet. We have acid flushed the engine and replaced the water pump and impeller. We thought that might have solved the problem, but it didn't completely solve it. What ended up happening is that we now push more water through the engine, which also created a backflow problem so significant that when we shut the engine off and sailed in anything but the most calm seas, we would have seawater running back through the exhaust and into the engine. Virtually every time we went sailing we wouldn't be able to start the engine on our return and found water in the oil AND carbuerator. Anyway, we fixed that by rigging a drain at the bottom of the muffler and draining the entire exhaust system as soon as we shut the engine off to sail.
However, when we motor for long distances (i.e. up coast to Santa Barbara) the engine still overheats only on port tack and only when the heel angle is plus 5 degrees), but heading up or switching tacks immediately, even if only for a few seconds, solves the problem for at least 1/2 hour.
We're convinced it is haunted. Thats the only possible explanation. However, finding an exorcist who is experienced with A-4 engines is a tall task indeed.
Jim McCone
Voice of Reason E32-2 hull #134
ted_reshetiloff
Contributing Partner
Siphon Breaker
Should you not have some sort of siphon break to stop the backflow probem instead of draining your exhaust?
Should you not have some sort of siphon break to stop the backflow probem instead of draining your exhaust?
Bill Sanborn
Member III
Heat riser
This sounds like a heat riser problem. The last time I replaced mine the outer/visible areas of the heat riser seemed perfectly normal, however when I took it apart the inner tube was corroded at the top.
As long as the engine was running the pressure from the exhaust gas prevented any salt water backflow into the engine. As soon as the engine was stopped any saltwater left in the heat riser between the lower level of the rubber exaust hose and the corroded top of the inner pipe drained back down into the exaust manifold and into the engine.
You might be able to see if this is the problem by removing the rubber exhast hose at the heat riser and peering in with a flashlight. The inner pipe should be visible and the top of it should be somewhat higher than the exhaust exit. The top of the inner pipe should also to be cut in a flat horizonal line. Any distortion would be evidence of corrosion. If it looks normal there is no assurance that it isn't corroded on some non-visible portion.
A long shot, by any chance does the rubber exhaust hose rise after it leaves the heat riser? It should be level or decline otherwise any water left in the hose would try to flow back into the engine.
Please let us know what you find.
This sounds like a heat riser problem. The last time I replaced mine the outer/visible areas of the heat riser seemed perfectly normal, however when I took it apart the inner tube was corroded at the top.
As long as the engine was running the pressure from the exhaust gas prevented any salt water backflow into the engine. As soon as the engine was stopped any saltwater left in the heat riser between the lower level of the rubber exaust hose and the corroded top of the inner pipe drained back down into the exaust manifold and into the engine.
You might be able to see if this is the problem by removing the rubber exhast hose at the heat riser and peering in with a flashlight. The inner pipe should be visible and the top of it should be somewhat higher than the exhaust exit. The top of the inner pipe should also to be cut in a flat horizonal line. Any distortion would be evidence of corrosion. If it looks normal there is no assurance that it isn't corroded on some non-visible portion.
A long shot, by any chance does the rubber exhaust hose rise after it leaves the heat riser? It should be level or decline otherwise any water left in the hose would try to flow back into the engine.
Please let us know what you find.