1996 GTX No Spark (787)

[gtxnoclue]

My son was riding the Seadoo and when giving it throttle it died & would not start afterwards. Engine turns over fine with no weird noises but no spark after charging/testing the battery (>10.5V when turning over). All fuses were good. Took apart the rear electrical box & found a little corrosion on some terminals. Disassembled & cleaned everything up. Tested the ignition coil (primary was 0.5 ohm & secondary with caps off was 12.3k ohm which seemed to match the specs). Plug caps measured 4.96k & 5.84k ohms (although the one that tested 5.84k didn't give consistent readings). Also tested the lanyard, start/stop switch, & delay timer (all appeared to be good). Put everything back together & same issue - no spark. Tested at the plugs with no spark & also did not get DC voltage at the white wire going to the ignition coil using a 12V automotive test light.

I don't have a trigger coil test harness to check for output at the magneto housing (ohm or AC Voltage). Not sure what to do next - wondered if there was a way to test this output without a test harness. The repair shop mentioned that they would likely pull the engine to remove the magneto housing to test the trigger coil & stator. Wondered if you can advise on any other tests or recommendations I can do myself before taking it to the shop & having the engine pulled (since I really don't want to try pulling the motor myself).

I also couldn't find any articles on removing the magneto housing while it's still in the hull (and if it's advisable or not). There was a reference to being able to do this (putting 2x4 under the engine & removing the front engine mount) but really no concrete instructions for doing this while in the hull. My other concern with trying this in-hull was if I could possibly mess something else up (eg the oil pump/system or having to adjust timing).

Advice would be appreciated. Thanks!

 

[Tony dee]

Did u check to see if the two ground wires on battery are connected well. If the small one is not connected it will crank but will not start.

 

[gtxnoclue]

Yes - had 2 wires connected to the negative post of the battery. The main ground as well as the smaller wire that goes to the rear electrical box. Was having problems with my speedo/temp sensor so it has been disconnected but didn't think that would be an issue.

 

[purple_people_eater]

My son was riding the Seadoo and when giving it throttle it died & would not start afterwards. Engine turns over fine with no weird noises but no spark after charging/testing the battery (>10.5V when turning over). All fuses were good. Took apart the rear electrical box & found a little corrosion on some terminals. Disassembled & cleaned everything up. Tested the ignition coil (primary was 0.5 ohm & secondary with caps off was 12.3k ohm which seemed to match the specs). Plug caps measured 4.96k & 5.84k ohms (although the one that tested 5.84k didn't give consistent readings). Also tested the lanyard, start/stop switch, & delay timer (all appeared to be good). Put everything back together & same issue - no spark. Tested at the plugs with no spark & also did not get DC voltage at the white wire going to the ignition coil using a 12V automotive test light.

I don't have a trigger coil test harness to check for output at the magneto housing (ohm or AC Voltage). Not sure what to do next - wondered if there was a way to test this output without a test harness. The repair shop mentioned that they would likely pull the engine to remove the magneto housing to test the trigger coil & stator. Wondered if you can advise on any other tests or recommendations I can do myself before taking it to the shop & having the engine pulled (since I really don't want to try pulling the motor myself).

I also couldn't find any articles on removing the magneto housing while it's still in the hull (and if it's advisable or not). There was a reference to being able to do this (putting 2x4 under the engine & removing the front engine mount) but really no concrete instructions for doing this while in the hull. My other concern with trying this in-hull was if I could possibly mess something else up (eg the oil pump/system or having to adjust timing).

Advice would be appreciated. Thanks!

there is a way to test the pick up coil without all the hassle, If its turning over like normal,take a 12volt test light & ground it on the engine & take the probe end & place it on the white wire going to the coil & hit start button & see if the light lights up..

Yes you have signal to coil,NO you dont have signal... in that case it could be two things,the ign module in front electric box is bad or the ignition pickup in the front cover is broken & needs to be replaced.

 

[gtxnoclue]

I may use incorrect terminology - if so I apologize. Just not real familiar with all the part naming & just want to clarify.

I assume the coil you refer to is the ignition coil in the back electrical box (not the pickup coil under the magneto housing. I've tested the ignition coil - no light on the white wire. Is there a way (without specialized tools) to identify if the problem is actually the ignition module in front box or the ignition pickup coil behind the magneto housing? I'd prefer not to open up the magneto housing if possible.

If I do have to open the magneto housing up:
* can it be done "In-hull"?
* if done "In-hull" - are there any instructions or special needs (eg oil pump removal, bleed, timing adjustment via MPEM, etc)?

Thanks for all your help!

 

[purple_people_eater]

yes it can be done in the hull, but imo its far easier to unbolt the motor, take the pump off, and remove the drive shaft from the coupler and then stand the engine up, remove the mag cover and see whats really going on inside there, could be the pick coil, could have broken the mag cup bolts. the best way to find out for sure is just to dig in.

yes, you'll have to re-bleed the oil system.

 

[gtxnoclue]

Thanks so much for your help. Been a few days since getting back to working on it. Being a relative newbie to repairs like this I really am hesitant to removing (or standing the engine up) for fear of messing something up worse - especially since I wasn't 100% certain the problem was behind the magneto housing.

Since I don't have a test harness, I talked to a mechanic about a sure way to test if I'm getting a signal from the pickup coil so that I don't tear into something & it not be the problem. He shared a trick where he pushes "Singer T Pins" into the connector, next to the wires you want to probe. Doing this allowed me to make sure I wasn't getting any signal from the pickup coil. At that point I felt pretty sure that it was something under the magneto housing.

Not wanting to pull the whole engine, I cut down a short 10mm socket & was able to get the bottom bolt off the magneto housing (with the front engine mount out of the way; with a wood block supporting the engine).

Pulled the housing off & like several posts have mentioned, the pickup coil was broken off it's bracket. So the next question is if I can splice in a new pickup assembly (290 965 648) since it doesn't look like there are any existing connectors to easily uplug the old & plug in the new. It looks like I can order that part separately so I assume this would work, but I don't want to create any issues. If so, do you recommend a specific splice type & method? Thanks!

 

[gtxnoclue]

Just learned how to remove wires from a Deutsche connector. Off to get a pickup assembly tomorrow. If all goes well I may be back on the water by the weekend.

 

[benstoker]

Sorry to revive an old post but I am working on my 787 now. Somewhat of the same issue (turns over but no spark). I have all of the bolts off the magneto housing and off the motor mount. How were you able to get the cover off with the mount in the way or were you able to remove the mount from the hull?

Thanks!

 

[gtxnoclue]

Not sure I'm a good one to give advice but I can share what I did (not saying it's the right thing to do but it did seem to work for me). I did remove the front engine mount from the hull. Before removing it I put a cut down 2x4 block under the front of the engine for support so it wouldn't damage anything (it was a pain working around it and it occasionally slid out but for the most part supported the engine). My biggest fear before taking the magneto housing cover off was that it wasn't actually a pickup coil issue. I felt much better after learning about & using the "Singer T pins" to ensure it was actually the pickup coil before I took things apart. That one bolt is a pain to get to isn't it? Hope that helps & good luck!

 

[benstoker]

Than you for the info. I was able to get the cover off today and unfortunately it wasnt the stator. The bottom bolt was a pain to get to but i took the exhaust manifold off and that made it a lot easier. I cleaned all of the connectors and what not which seemed to improve the resistance tests that i was running. I'm putting everything back together tomorrow and will see if that helped with the no-fire issue. Did yours end up being a wiring issue or a magneto issue?

 

[gtxnoclue]

My issue was the pickup coil. Broken mount which was actually pretty easy to fix once I figured out how to remove wires from a Deutsche connector.

 

[benstoker]

Thanks gtxnoclue. Mine ended up being the ignition coil. The housing had cracked on the back and the insides had started melting out of it. Pretty funky stuff.