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#1
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Mercruiser 5.7L stalls on acceleration
Confusing problem. Had a coil short while underway and accelerating.
Would not restart. Was towed in. Tested the coil (lifted the negative wires and showed short on both posts). The coil was the original (17 years old). Replaced the coil with OEM part, spent the rest of the day cruising with no problems. The next day, the throttle release broke and I took the remote control apart and replaced the broken plastic part and reassembled. Took the boat out and upon acceleration (climbing past 3000 rpm's) the engine bogged and shut off but this time, it restarted. Idled around a bit, reved up again, and at around 3000 rpm's, it shut down. Restarted and idled back into port. Reving the engine out of gear does not cause the problem, only under a load. Even though I had the coil problem, since the last thing I was messing with was the remote control assembly, I highly suspect the something related (interupter switch on the engine?). I noticed the top cable was parting at the crimp connection and the cable would pop in and out of the crimp on movement. Also, the bottom control cable was flopping on forward/reverse movement of the throttle. Questions: Is it possible that the bad cables are causing the engine to shut off at 3000 rpm under load only? Could this problem have originally killed the old coil? Is it possible to but a meter on the interupter switch and watch for opens when moving the throttle to full? |
#2
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Mercruiser 5.7L stalls on acceleration
On 7 Oct 2005 13:45:30 -0700, "bayplyer" wrote:
Confusing problem. Had a coil short while underway and accelerating. Would not restart. Was towed in. Tested the coil (lifted the negative wires and showed short on both posts). The coil was the original (17 years old). Replaced the coil with OEM part, spent the rest of the day cruising with no problems. The next day, the throttle release broke and I took the remote control apart and replaced the broken plastic part and reassembled. Took the boat out and upon acceleration (climbing past 3000 rpm's) the engine bogged and shut off but this time, it restarted. Idled around a bit, reved up again, and at around 3000 rpm's, it shut down. Restarted and idled back into port. Reving the engine out of gear does not cause the problem, only under a load. Even though I had the coil problem, since the last thing I was messing with was the remote control assembly, I highly suspect the something related (interupter switch on the engine?). I noticed the top cable was parting at the crimp connection and the cable would pop in and out of the crimp on movement. Also, the bottom control cable was flopping on forward/reverse movement of the throttle. Questions: Is it possible that the bad cables are causing the engine to shut off at 3000 rpm under load only? Could this problem have originally killed the old coil? Is it possible to but a meter on the interupter switch and watch for opens when moving the throttle to full? I'm no mechanic, but it would seem that you'd be pushing much more cable through the line to reach 3000rpm under load than you would in neutral. Your description of the cable parting doesn't sound good. -- John H "The trouble with our liberal friends is not that they're ignorant: It's just that they know so much that isn't so." Ronald Reagan |
#3
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Mercruiser 5.7L stalls on acceleration
I always suspect the things that were worked on last. Alphas rely on the
drive's desire to stay in gear to activate the interupt switch. It is the tension that builds up onthe cable housing that activates the switch. This makes the behavior different when the engine is not running. Among other things that's why they are such a pain to adjust. The interupt switch is only for getting it out of gear so you can disconnect it temporarily for a test. I would suggest you get to open water, disconnect the interupt switch, then test your theory. It can be a bear to get away from the ramp or dock without it. You will need to turn the key off to get it out of gear so be prepared to do that. "bayplyer" wrote in message oups.com... Confusing problem. Had a coil short while underway and accelerating. Would not restart. Was towed in. Tested the coil (lifted the negative wires and showed short on both posts). The coil was the original (17 years old). Replaced the coil with OEM part, spent the rest of the day cruising with no problems. The next day, the throttle release broke and I took the remote control apart and replaced the broken plastic part and reassembled. Took the boat out and upon acceleration (climbing past 3000 rpm's) the engine bogged and shut off but this time, it restarted. Idled around a bit, reved up again, and at around 3000 rpm's, it shut down. Restarted and idled back into port. Reving the engine out of gear does not cause the problem, only under a load. Even though I had the coil problem, since the last thing I was messing with was the remote control assembly, I highly suspect the something related (interupter switch on the engine?). I noticed the top cable was parting at the crimp connection and the cable would pop in and out of the crimp on movement. Also, the bottom control cable was flopping on forward/reverse movement of the throttle. Questions: Is it possible that the bad cables are causing the engine to shut off at 3000 rpm under load only? Could this problem have originally killed the old coil? Is it possible to but a meter on the interupter switch and watch for opens when moving the throttle to full? |
#4
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Mercruiser 5.7L stalls on acceleration
Sounds like the cable tension is critical and I need to replace them.
Will I run into the cable adjustment brain damage by replacing the two cables that run from the remote control to the parallelogram? |
#5
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Mercruiser 5.7L stalls on acceleration
The service manuals have very specific instructions for how to adjust the
shift cable and the switch after you replace it. A lot of people have trouble with it though. Imho it's a bit of a rig. I'm surprised they couldn't figure out something more straight forward. In theory accelerating is not supposed to have any effect, The control should only be moving the throttle cable once it has shifted into gear. The throttle cable is completely independent of the shift cable and is easy to adjust. But since you already had cable trouble I'm still inclined to suspect it first. "bayplyer" wrote in message ups.com... Sounds like the cable tension is critical and I need to replace them. Will I run into the cable adjustment brain damage by replacing the two cables that run from the remote control to the parallelogram? |
#6
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Mercruiser 5.7L stalls on acceleration
"JamesgangNC" wrote in message link.net... The service manuals have very specific instructions for how to adjust the shift cable and the switch after you replace it. A lot of people have trouble with it though. Imho it's a bit of a rig. I'm surprised they couldn't figure out something more straight forward. In theory accelerating is not supposed to have any effect, The control should only be moving the throttle cable once it has shifted into gear. The throttle cable is completely independent of the shift cable and is easy to adjust. But since you already had cable trouble I'm still inclined to suspect it first. "bayplyer" wrote in message ups.com... Sounds like the cable tension is critical and I need to replace them. Will I run into the cable adjustment brain damage by replacing the two cables that run from the remote control to the parallelogram? The cables can be mis adjusted so that there is movement in the shift cable after the drive is in gear. this will put tension on the interrupter lever and it could trip the interrupter switch. Often people try to compensate for worn or damaged linkage and sterndrive parts by misadjusting the cables. This could lead to more problems. When everything is in good mechanical condition, the cables are easy to set up. |
#7
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Mercruiser 5.7L stalls on acceleration
If you ignore everything in your post but the symptoms, it sounds like a
carburetor problem. I had the same thing. Need to disassemble and soak in carb cleaner then flush the jets and passages with a can of carb cleaner. "bayplyer" wrote in message oups.com... Confusing problem. Had a coil short while underway and accelerating. Would not restart. Was towed in. Tested the coil (lifted the negative wires and showed short on both posts). The coil was the original (17 years old). Replaced the coil with OEM part, spent the rest of the day cruising with no problems. The next day, the throttle release broke and I took the remote control apart and replaced the broken plastic part and reassembled. Took the boat out and upon acceleration (climbing past 3000 rpm's) the engine bogged and shut off but this time, it restarted. Idled around a bit, reved up again, and at around 3000 rpm's, it shut down. Restarted and idled back into port. Reving the engine out of gear does not cause the problem, only under a load. Even though I had the coil problem, since the last thing I was messing with was the remote control assembly, I highly suspect the something related (interupter switch on the engine?). I noticed the top cable was parting at the crimp connection and the cable would pop in and out of the crimp on movement. Also, the bottom control cable was flopping on forward/reverse movement of the throttle. Questions: Is it possible that the bad cables are causing the engine to shut off at 3000 rpm under load only? Could this problem have originally killed the old coil? Is it possible to but a meter on the interupter switch and watch for opens when moving the throttle to full? |
#8
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Mercruiser 5.7L stalls on acceleration
Thanks Jeff. After scouring the newsgroups, there seems to be numerous
problems that match to the symptoms. Most folks say the majority of problems are ignition circuit related, unless you suspect this in which case, the problem is fuel related??? The first three in the list are ignition related... 1. Arcing in the plugs, secondary wire, or distributor Inspect/clean replace 2. Coil breaking down Swap 3. Shift interrupter, cable tension Disconnect and test underway 4. Fuel accelerator pump/varnished carb Replace/soak 5. Vacuum in the gas tank, lines Remove cap to test, clean vents 6. Water, debris, bad gas Check filters, fuel seperator, clean or drain I've already done 2 and I can probably test 3, 5, and 6 without messing anything up. After that, I'll probably get some help. |
#9
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Mercruiser 5.7L stalls on acceleration
I agree with your suspicion about the shift cable being a possible source of
the trouble. Temporarily disconnecting the interupt switch would be an easy and positive test to confirm. "JIMinFL" wrote in message link.net... "JamesgangNC" wrote in message link.net... The service manuals have very specific instructions for how to adjust the shift cable and the switch after you replace it. A lot of people have trouble with it though. Imho it's a bit of a rig. I'm surprised they couldn't figure out something more straight forward. In theory accelerating is not supposed to have any effect, The control should only be moving the throttle cable once it has shifted into gear. The throttle cable is completely independent of the shift cable and is easy to adjust. But since you already had cable trouble I'm still inclined to suspect it first. "bayplyer" wrote in message ups.com... Sounds like the cable tension is critical and I need to replace them. Will I run into the cable adjustment brain damage by replacing the two cables that run from the remote control to the parallelogram? The cables can be mis adjusted so that there is movement in the shift cable after the drive is in gear. this will put tension on the interrupter lever and it could trip the interrupter switch. Often people try to compensate for worn or damaged linkage and sterndrive parts by misadjusting the cables. This could lead to more problems. When everything is in good mechanical condition, the cables are easy to set up. |
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