No Spark to Distributor - Voltage diagram included |
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Have Fun!
Newbie Joined: April-24-2014 Location: Columbus Ohio Status: Offline Points: 17 |
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Posted: May-17-2014 at 1:34pm |
Hey everyone!
Update on the 89... Dipped and rebuilt the carb to solve my idle issue. Took it out for a shakedown run everything ran great except an oil leak on a valve cover gasket. Back to the garage, fixed the leak, then back to the lake and the boat won't tun over... No spark at points.... Very confused what caused this literally overnight. Been chasing my tail around the wiring harness this past week, We've got a new battery, starter selonoid , ballast resistor, and Coil, voltage has improved but still no spark. Performed and audit on the electrical system this morning and it appears I'm loosing a volt at the ignition switch and approximately 2 volts at the alternator. leaving me with only 4.5 volts out of the ballast resistor into the coil. My questions: Is it normal to loose 2 volts in the alternator, if not suggestions to improve voltage, and how about ignition, is loosing a volt there normal as well? Thanks guys! Here's map of my voltage, voltage readings in green. |
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
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Can you go over the order of events? When I was a kid and I lost something, my father would always say, when was the last time you remember having it? Which is kind of an annoying question in the heat of the moment when you just want to find something. But, it often works.
So, it was running after the carb rebuild, then you did the valve cover gasket and it wasn't running, then you replaced the electrical stuff? If I was going to take a quick shot in the dark, I was thinking something with the carb electrical choke. Since you were just working on it. Maybe the spring gave up the ghost and shorted out, giving the positive wire a direct path to ground and drawing everything down. Also, I don't think boats have this, but a lot of cars use valve cover bolts as a tie down point for a wiring fastener, or an actual ground. Did anything become disconnected or disturbed when you were working on the new gasket? |
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Have Fun!
Newbie Joined: April-24-2014 Location: Columbus Ohio Status: Offline Points: 17 |
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Order of events:
Rebuilt carb, installed carb, fired up in driveway, set idle, lake test, discovered oil leaking from starboard valve cover. Removed exhaust manifold, removed valve cover, adjusted valve gasket (gasket slipped behind middle bottom bolt on instillation) reinstalled cover and exhaust manifold, back for Lake test #2 and boat won't turn over. Back to the garage, Spark plug to block - no spark, pulled distributor to check point gap & points - no spark. Boat has been sitting for the last 2.5 years thought the shock of running the boat to the system may of fried coil, installed new battery (original battery was week), installed new coil and starter solenoid. (solenoid was for good measure.) Still no spark. Stumped I took the boat to local mechanic for some advise, his recommendation always replace ballast resistor when replacing coil. Thought new coil is fried because ballast resistor went out and was the cause of all problems. Ordered new coil and ballast resistor, installed, still no spark. I originally checked everything with a circuit tester, this morning I went through the system with a volt meter thinking I'm loosing power someplace the circuit tester isn't telling me. Went though every electrical connection on the engine this morning as well, everything got hit with emory cloth and dielectric grease, all connections are good. Just took a look at the Choke, Spring internally seems to be complete and functioning properly. Also re examined the valve cover and manifold, all wiring seems to be good. Only guess is that maybe some oil from the gasket somehow got into the starter and is causing a short of some sort? But that's just a wild theory, havet examined the starter yet, not sure if that's even possible. Thanks for the insight! |
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
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Did you happen to leave your key on for an extended period while you were doing some of your work? I've heard it's possible to burn up the points themselves if the key is on a long time with the boat not running.
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Have Fun!
Newbie Joined: April-24-2014 Location: Columbus Ohio Status: Offline Points: 17 |
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Points and condenser appear to be in great shape, no burn marks. Key is always turned off in-between checking for issues.
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
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What voltage are you getting to the ballast resistor and then to the coil? You should have about 8 volts to the coil. Hook up a spark plug directly to the coil. Then, remove the ground wire going to the coil from the distributor. Ground it to saturate the coil. Removing it from ground you should get a spark. This will tell you if the coil is bad. Ohm out the point set with it open and closed. You should get a near zero Ohm reading when it's closed.
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Have Fun!
Newbie Joined: April-24-2014 Location: Columbus Ohio Status: Offline Points: 17 |
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Getting 9.4 to the resistor with 4.5 to the coil, new coil and resistor so that shouldn't be an issue.
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21171 |
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If the engine won't turn over, then you have a starting problem, not an ignition problem. 12.2v at the battery means it's dead. Try charging it.
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
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You should be getting close to the battery volts to the resistor. As Brian mentioned, disconnect the choke to take it out of the scenario and get the voltages again. Are the volt readings during cranking? Is it turning over or not as Tim has questioned? |
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Have Fun!
Newbie Joined: April-24-2014 Location: Columbus Ohio Status: Offline Points: 17 |
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Dissembled and inspected the choke, everything is functioning properly. I'll remove choke wires and check volt readings again. Voltage was checked with ignition turned on, engine not cranking.
Motor turns over just fine (strong in fact) just doesn't fire due to lack of spark. Any random grounds hiding on the engine I may have overlooked? Thanks! |
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
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Make sure you're not grounding the coil directly to the block the coil "-" doesn't mean negative in the traditional sense here. It's just for a wire coming from the distributor and a wire for the tach signal.
Also, make sure the body of the ballast resister isn't some how grounding to the block. I've never heard of this happening actually, just trying to figure out the big drop from one side of the resister to the other. I know mine has a group of wires that are sleeved together and run on top or near the valve covers. Still suspicious about these being disturbed. Meaning, they had to be moved most likely, and the wires have some years on them. Just wondering if some broken down insulation could have started touching. |
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MustangMadness
Senior Member Joined: April-15-2014 Location: Seacoast NH Status: Offline Points: 114 |
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First I would make sure the points are spotless and gapped correctly.You should be getting battery voltage (12+v) to the input side of the ballast resistor and about 10v out. Run a jumper from the battery + (or from battery cable terminal on the solenoid) to the + side of the coil and turn it over. If it doesn't start, replace the coil and/or points and condenser. Don't leave this jumper connected for long without the engine running, you WILL burn your points. If it does, you have a wiring issue somewhere to the ballast resistor or a dead/failing battery.
It is odd that the problem occurred after R&Ring the valve cover gasket. |
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Have Fun!
Newbie Joined: April-24-2014 Location: Columbus Ohio Status: Offline Points: 17 |
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Weakest link in the system was the points grounding themselves out. They were clean and gapped properly however someplace in the hinge portion something was compromised and at certain points would break current. New points and condenser and it's running smooth.
Thanks for the advice. -Cheers! |
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Bri892001
Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947 |
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Nice! Glad you found it
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