Please Help Mercury 200 EFI Wont Start or Fire

[BamaBass]

My Mercury 2001 200 hp Efi won't fire. It turns over but wont fire not even with starter fluid spray. Ive replaced the fuse on the right side of the engine but that didn't work. It acts as if the kill switch is pulled but it isn't. The spark plugs aren't getting any fire and aren't arching. I have a tournament this weekend so any help would be greatly appreciated.
Thanks

 

[sschefer]

Re: Please Help Mercury 200 EFI Wont Start or Fire

My Mercury 2001 200 hp Efi won't fire. It turns over but wont fire not even with starter fluid spray. Ive replaced the fuse on the right side of the engine but that didn't work. It acts as if the kill switch is pulled but it isn't. The spark plugs aren't getting any fire and aren't arching. I have a tournament this weekend so any help would be greatly appreciated.
Thanks

I've been doing some studying on the the EFI engines (not Optimax DFI's) and I'm in no way a pro but they are pretty simple. The most likely culprit in a total lack of fire is a short to ground. That short can be in the ECU. The fastest way to test is with a known good ECU but .... The caveat is that if it's a short to ground that's outside the ECU, you could blow the replacement ECU and they aint cheap.

The best solution is to take it in and have the diagnostics run on it. If you have a buddy with the right equipment you might find it quick and get back out on the water today. Might be something really simple like a bad connector/corroded connector. Check them all first and clean them with CRC contact cleaner.

 

[Talonz82]

Re: Please Help Mercury 200 EFI Wont Start or Fire

I would like to add to a previous reply, check your means of control, on your merc it will be a black wire with a yellow tracer, you can do this by unplugging your main engine connector at the engine and using a remote start switch. When you have a no spark on all cylinders, most probable cause is a short or ground in your control circuit or worst case a bad ECM. Check your control circuit and eliminate your safety lanyard and nuetral safety switch. I use the Merc CDS and most sensor faults won't cause a total no spark. If you get past this and still no spark and you have a good VOM with a DVA you can check all your inputs to the ECM, ECMs are sensitive, garbage in you get garbage out, however, the lack of or low stator or trigger voltages i have found result in only weak spark or lack of on some cylinders, but not all. Good luck, let us know how you make out.

 

[Faztbullet]

Re: Please Help Mercury 200 EFI Wont Start or Fire

On a Mercury EFI system the ECU has very little control over the ignition system. The ECM controls fuel flow and if it could short the ignition, it would be the inner switchbox only(early models). The later models are a different story with "bobbin" style stator, they use a 20 amp fuse for ignition coils and a ground from the ECU to control spark advance. If a 2001 you should have the stator/trigger style with CDM's. If you have no spark check the kill circuit as in earlier post(blk/yel wire). Check ALL your connections as this engine uses the CDM modules and share a common ground, if ground is missing it can cause all cdm modules not to fire. If that fails your back to a stator or trigger problem.

 

[j_martin]

Re: Please Help Mercury 200 EFI Wont Start or Fire

I second the kill circuit (black/yellow wire) theme. If you disconnect those wires at the switchboxes, that will totally eliminate it as a source of the no spark problem. If you do that, fashion a jumper between the switchboxes, and another wire hanging off that you can ground to kill the engine. To restate that, the engine is stopped by grounding both kill terminals, one on each switchbox.

Another thing. Never put anything but 2 cycle mixed fuel into this engine. Starting fluid, carb cleaner, etc. is real hard on the engine as it does not have any lubricant in it, and the preignition is causes can do damage.

hope it helps
John