1997.5 Gsx 951 has weak spark

[Bbarnumboy]

Hi guys, I hope this is in the right sub forum.

Last fall on the last planned ride of the season, my seadoo unexpectedly lost all power at full throttle while at top speed. It did not start running rough, it just completely cut all power and I almost flew off the ski

Turns out I lost spark or most of my sparks power. The ski was having a hard time starting before that ride as Well, so this was something that had been in the making it seems.

Here is what I have done so far

-Confirmed all fuses are good and working
-Confirmed ground wires, clean & secure
-Fully charged battery
-Full gas and oil
-Compression test confirming good comp
-Brand new, properly gapped spark plugs
-Brand new starter (it was having issues)
-Brand new bendix gear
-Brand new Stator/magneto
-Brand new ignition pickup
-Tested spark plug wires
-Trimmed wires back and reinstalled boots
-Start button seems to function properly

My guess at this point is that I am down to the ignition coil pack, that the spark plug wires connect to in the rear electrical box, or an MPEM issue. I get a good 2 beeps when the key is engaged and the starter is working perfectly. I confirmed spark but it is very weak and yellow instead of strong and Blue. The engine just barely tries to start but it does not have enough. I dont know how these ignition systems spark, but it seemed like my spark is very sporadic and sparking more than it should. Maybe my model has a double spark? I am not completely sure.

I have a used, good working ignition coil pack coming tomorrow that I will be testing out. I never found a procedure for testing the coil itself. It has 2 wires for spark plugs and 2 posts, can it be resistance checked by itself with an ohmeter on the bench? I couldn't find this procedure or any resistance values for the coil pack itself. I would like to know how to test it so I can compare it to the new one I receive.

Sorry for the long post, I am so close to finding this issue out, but I am tired of throwing parts at it and the last part to try is an expensive mpem after I try out the new coil pack tomorrow. Any information or extra ideas would be very much appreciated. We just hit 73 degrees this last weekend, it's almost time to start riding again!

Thank you

 

[Seadoo35]

My GTX had a weak spark as well. The previous owner replaced the coil thinking it was that but eventually i found the coil was wired wrong. The grounds were not hooked up properly, after fixing that it now has a strong blue spark. I would say its most likely something to do with your coil.

 

[Bbarnumboy]

Any idea how to resistance test across the coil, or the ohms range?

 

[Seadoo35]

Any idea how to resistance test across the coil, or the ohms range?

I don’t oersonally I didn’t have to go that far. But I’m sure you can look into this forum or google and find it. Sorry

 

[mikidymac]

Download the service manual for free. It will tell you how to test it. Keep in mind the resistance test doesn't always tell you the truth. Sometimes on these you just have to swap parts.

 

[Bbarnumboy]

I have the manual and can only find tests for the magneto, and timing pickup

 

[mikidymac]

Page 08-02-14 and 08-02-15 describes the coil test in the 1998 service manual.

 

[tobytd]

section 7 electrical sub sect 2 ign sys pg 15 in your manual - coil test 97 manual

 

[Bbarnumboy]

Thanks, I'll try it out. Somehow missed that when reading through the magneto testing

 

[tobytd]

Mikidymac please give details about 'Grey Ghost' white motor, lean carbs, pipe etc.

 

[mikidymac]

Actually @Matt Braley knows more about the white 947 than me. Basically it was too lean from the factory and the port timing caused issues from what I remember. They changed the timing and carbs the next year.

 

[Bbarnumboy]

My engine was rebuilt by full bore 2 years ago, he said the only white engine part left was the bottom end I believe, the jug and head were newer. I had the carbs rebuilt as well and I set the jets to the spec of the later model which richened up the PTO carb I believe by about 1/4 of a turn. Looking at my plugs, I definitely haven't been running lean from what I can see.

 

[Icantswim]

My engine was rebuilt by full bore 2 years ago, he said the only white engine part left was the bottom end I believe, the jug and head were newer. I had the carbs rebuilt as well and I set the jets to the spec of the later model which richened up the PTO carb I believe by about 1/4 of a turn. Looking at my plugs, I definitely haven't been running lean from what I can see.

I just had his signature series done to my 951...

 

[Matt Braley]

The white 951 was rushed out for a couple reasons. One is that they had to make 500 models before it could registered as a production model and therefore be legal in racing. The other is that they had to register it with the EPA. This is why it was tuned on the lean side and has the solenoid attached to the metering diaphragm side of the carbs.

The "grey Ghost" was the fastest ski on the water in 97. It taught BRP some lessons though. They rejetted the carbs, dropped the electric carb solenoid and changed the orientation of them as well. They de-tuned things (unfortunately) to try and improve reliability. The timing curve was less aggressive in following 951's and the exhaust pipes were 2mm smaller internally also.

The 97.5 is also the first model with the 155mm pump. It is a small hub 155 pump though different from all following models.