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I have a 2001 Mercury 240hp Sportjet engine with the older type ECM that has no spark on any cylinder. Stator ohms out OK, Any other ideas?
Welcome,this question may need more than a single answer. Please post back with additional questions on this at any time.If you are not getting any spark, you can verify this with a timing light.Check the emergency stop switch. Disconnect it from the circuit and crank the engine. I would recommend getting a spark tester to do your spark test. A plug held against the block is a poor substitute on the CDM systems.If still no spark;Check battery voltage (RED/YEL Lead) @ ignition coils.Check for blown fuse (C15).Check battery voltage to fuse from main power relay (PURPLE Lead).Check for shorted stop wire (BLK/YEL).Check crank position sensor setting [0.025 in. – 0.040 in. (0.64 mm – 1.02 mm)] fromflywheel or for defective crank position sensor.Defective ECM.Power Supply:Clean and inspect remote control male and female harness connectors.Try these and it should tell you where the problem is. Rarely do I see the ECM go bad, usually a bad kill switch or loose, corroded, broken connection or wire.
I guess that I should have mentioned that the engine is out of the boat and on the workbench. We are using a spark tester and I just noticed a sticker on it indicating that it is a 2000 model, not a 2001 if that makes a difference. The coils each have 4 wires going to them and I don't see a red/yel wire on them. Nor do I see a purple wire anywhere around the relay. Also, I don't believe it has a Crank Position Sensor and how do we test for a shorted stop wire? Thanks, Paul
I just got the MEDS computer to hook up and it is saying all three triggers A, B and C are "Fail"
Can you give me the serial number of the engine?What are the colors of the 4 wires at the ignition coils?Are you ale to crank the engine over?
The 2000 is a different engine from the 2001. Pull the connector off each CDM and check the black/yellow to ground with the key ON.Check the trigger coils resistance, Red to white, Blue to purple and Black to yellow all should be 1100 to 1400.What do you get?
Jeff, The engine is model #: S240J30WS and the Serial # XXXXX: OE376065. Each coil has a White/Grn, a Blk and a Black/Yellow. Then there is a fourth wire that varies with the cylinder - White/Blk, Dark blue/White, etc. And Yes, we have a keyswitch hooked up to the master plug that we use to run all of these sportjet engines. We specialize in Sportjets, but can't get this one figured out.
The Trigger Resistances are all around 1260 and the Black/Yellow wires to ground are .89 volts on all.
With the key on and the harness disconnect from the CDM check resistance on the black/yellow wire in the connector harness to ground. If you get anything the harness, key switch etc is bad.You have proper resistance on the trigger coils. So they should be OK.Basically you have 4 components, the charge coils, the trigger coils, the control module and 6 CDM ignition modules. And the key switch and harness.If the black/yellow wire is not to ground with the key on and to ground with the key off the switch and harness are OK.Your trigger tests OK on a resistance test. Rare would be the one that test good on resistance but bad running.The charge coils green white and white green about 400 ohms +-. Check the flywheel magnets are securely in place and not damaged.If the charge coils check OK then chances are the control module is faulty.
Jeff, With the key on I am getting around 7000ohm and off around 15000 on all coils.
even if I disconnect the key harness. The charge coils are 411 ohms. The flywheel looks good. Do you suppose a wire on the main harness is pinched to ground somewhere?
Wierd thing is that this engine ran fine in the boat it came out of. Sat on our shelf for a year and then didn't run once we sold it last week. I tried the key harness on another engine and it started right up so I don't think it is the key switch. Should the engine have spark without the key harness hooked up and jumping the starter solenoid?
Your engine has a harness so the stop circuit goes directly to the CDM. All you are looking for on the stop circuit is no continuity or continuity. Ground or no ground.The charge coils are OK from your replies as are the trigger coils.The stop circuit appears to be OK. One bad CDM would not cause the loss of spark to all the other CDM's.In your case it would appear the control module is bad. Everything else is checking OK, so by a process of elimination we come to this conclusion.If you have one from another engine swap them and see.
Just swapped out the control module with no better results. I have also swapped out the ECM. All parts are coming from a running engine.
Weird.Unplug all of the CDMs and check the black yellow to ground. The connect one CDM at a time, the resistance will raise each time you connect a CDM. With the previous tests and these you should find the problems as we have checked virtually everything. If you have a peak reading voltmeter we can further check the stator and trigger coils.Is there any "potting" material running down, melting from the stator? No charred wires? Check all wires in the harness for signs of overheating and corrosion. Check for swelling in all of the harness.
I just discoverd that if I unplug the black/yellow wire at the top of the main harness going down to all 6 CDM's, I have good spark on all 6. Is there a sensor that would kill the spark?
You have a problem from there back. Did you check the key switch? Also you should have continuity with the connector connected when you tested the B/Y at the CDM with what you are saying. Your stop circuit is grounded that;s why no spark.
Experience: 35 years experience, Certified Master Technician, All Major Outboards, Sterndrives, Hi-Performance
I just figured it out! Unhooked the Rev Limiter and still had spark. Replaced it and we're still good. Will try running it now. Thanks for all your help.
Great.