98 GTX LTD intermittent electrical issue

[way2qk4u2c]

Give you some back ground on the ski

98 GTX LTD about 80hrs on it
Ran great for about 2 seasons since i have had it.
One day on the lake going full throttle on a choppy lake the ski started to bog and misfire. It then eventually would just die. Sometimes i could start it right back up and other times i would have to reset the lanyard. After it starts the hesitation and bog was still there and then dies pretty fast. One time i was able to limp it home while maintaining it under 3500rpm. The other issue is the ski will go completely dead for no reason, the gauges will not come on by hitting the start button with the key off. Usually we let it sit for a day and the gauges will come back on. While this is happening the battery voltage is at 12.6 which should be enough to light up the gauges.

We also noticed the pulse fuel pump nipple was cracked so i replaced this and the issue is still there. I thought maybe we had a fuel issue at first which we very well did but now we also have an electrical problem.

I also think the buzzer is broken because it never beeps anymore. Another item on the list to buy

Things we done for good measures
1. Replaced all tempo fuel lines with new black lines
2. Rebuilt the carbs and changed the filters
3. Replaced broke pulse fuel pump cover.
4. Replaced fuel float to fix the fuel gauge and stop the beeping (however the buzzer broke from beeping all the time)
5. Cleaned the main ground to the starter from the battery - ohm it out and it was good (shouldnt be shorted inside)
6. Cleaned the ground on front of mag side of carbs
7. Fuses are all good
8. Checked the coil and electrical box and cleaned and secured the grounds there as well.

Next step for me is to meter power and ground at the mpem but this problem is intermittent and the mpem wakes up sometimes and then doesn't so if its working my tests will do no good. I have to somehow do the test when everything is dead. However when the mpem is awaka the ski runs like crap. I didnt pull the 15amp fuse while running to see if the rectifier is bad but that is next as well.

Anyone have this experience or help me trace this issue. Does this sound like a ground problem? Why would a mpem shutdown, can a stator do this to the mpem?

 

[way2qk4u2c]

So after metering some more wires we discover this
1. The main red wire supplying power to the MPEM shows 12.6v
2. The main ground from MPEM to engine ohm out to 0.00 which is good
3. Meter the ground and power at MPEM and shows 12.6v
4. Meter where the gauges get power from MPEM while pressing start button and no power- dead.
We believe the MPEM is dead, however we also notice if we meter the 15amp fuse on the MPEM and press the starter it goes from 12.6v to 4.5v? Is this a sign of a bad battery? i wouldn't think it would drain that much even when the starter is not actually turning on at all.

Anyhow does anyone have a MPEM for sale?

 

[Mickirig1]

Contact Minnetonka4me. He has parts and can test and replace the MPEM. He carries new and used ones. He can test it and even make you spare keys .

 

[- BiRkS_]

Check your wires where they go through the hull and into the hood. I had a similar problem where the seadoo would only run with the hood up. Worth a shot. (you will have to cut the black outer wire wrap.

When you run the ski, does it sound like it rev limits or boggs? I had a regulator go bad and had to cut the 3 stator wires to test. (then spliced in a 787 external voltage reg and it works great now!)

 

[way2qk4u2c]

Check your wires where they go through the hull and into the hood. I had a similar problem where the seadoo would only run with the hood up. Worth a shot. (you will have to cut the black outer wire wrap.

When you run the ski, does it sound like it rev limits or boggs? I had a regulator go bad and had to cut the 3 stator wires to test. (then spliced in a 787 external voltage reg and it works great now!)

However with the hood up or not the entire ski is dead. With or without the key we have no power coming out of the MPEM anywhere. We have good power to the MPEM but nothing out so this leads me to a bad MPEM and have nothing to do with the stator, key, post, dess etc...

I contacted Minnetonka4me about a MPEM- thanks

 

[way2qk4u2c]

Unbelievable update on this one. So i buy a MPEM from Jess which is Nick (Minnetonka4me) and we plug it in and the ski is still DEAD. More and more we looked turns out its not the MPEM being the issue. I started looking at the wiring schematics closer and trace my grounds again. So for a test i jumped the battery ground terminal to the ignition coil ground spot and the gauges and ski came alive. This told me the engine is not getting a good ground to complete the loop. We did fix the main ground to the engine before all of this but turns out the bracket the ground is on was loose and making an intermittent connection, if we wiggle it the gauges would flicker on and off. I can't believe this. Well now we have an extra MPEM lol go figure.

Next on the list- replace buzzer? any recommendations instead of buying the seadoo part that is expensive.

 

[Mickirig1]

Radio Shack has a buzzer that you solder onto the leads. I got one from a electronic suppley place. Try to get the 65 or 85 DB ones 12 volt suppley

 

[way2qk4u2c]

I went to radio shack and got the beeper- put it in and works perfectly. So another update- a bad one too

Went and took the jetskis out for a test to make sure its working. Well she ran perfect and i mean perfect for about 4 hours. We were just about to go home only 5 more mins and we would have been on the trailer going home. I was doing some donuts and i tried coming out of a sharp one and giving it gas all of sudden no power and died. I started it back up but it struggled to go anywhere. I let it sit to see if it was tired and such so about 10 minutes goes by i start it up and still no power at all. I limp it back to the dock and pull the spark plugs sure enough the electrode is bent in and small bearing balls are wedge inside of it. We get it home and pull the top end cover off and see one piston grey and broken pieces while the other one is perfect with oil. My question is what caused this:
1. Oil starvation?
2. Lean condition?
3. Water ingestion
4. Old tired parts
5. Rod bearing failure from what?

ill post pics soon.

great day for 4 hours then crappy day

 

[way2qk4u2c]

 

[Mickirig1]

Bummer! You find one Gremlin and another kicks you in the head!

 

[Minnetonka4me]

Looks like it was ingesting water.

 

[way2qk4u2c]

I know right...crazy. We had a blast on these things finally from fixing all the gremlins and now this happens.

So how does it ingest water? does it come in from the exhaust side or the intake side?

I'm assuming the intake side right?
Question the intakes have that wide black box and then 2 ports that come up over the engine. Then there is these rubber things that kinda protect the open ports for these things. We forgot to put those rubber pieces back on would this have been the reason or is the water ingestion still an issue with them on since the air intake is on the bottom of the hull and could still take water in?

I saw that the PPG makes a nice air filter kit along with rejetting the carbs.

Hate to spend 400 bucks on a top end to just ingest water again. that will be frustrating to say the least.

 

[Mickirig1]

We have owned our two ski's going on a year. These machines are a steep learning curve. Even if you have wrenched alot of stuff. No doubt, figure out what happened before you fix the latest Gremlin.

 

[brucegregory]

there is a problem with the 1998 gsx limited running lean i saw it reported on R&D website. it says to adjust the oil pump cable so it supplies more oil to the engine. also i learned a long time ago. to add a little extra oil in the gas.i have a ratio rite cup and i put a extra 100;1 mixture in the fuel. this will assure the motor doesn't run lean.looks like you need a total rebuild now. that really sucks. stay away from sbt engines heard lots of bad things from a friend who has a shop and won't even use them anymore

 

[way2qk4u2c]

anyone deal with full bore online for rebuilding engines?

 

[Minnetonka4me]

Never heard anything bad....which is usually good!

 

[way2qk4u2c]

So i'm trying to figure out the root cause of the failure. After looking at it closer the PTO cylinder still has the cross hatching on the cylinder and shows that it's in really good shape. The MAG cylinder that blew has a stressed crack down the piston and the skirt is half broken off which contributes to the grey color and all the debris which contributed to scratching the cylinder and eventually pushing the spark plug in. More i think about it i dont think this is water ingestion because most ppl say water ingestion causes bent rods and usually no scoring on the piston? Also the wrist bearing and rod bearing are in good shape. If it was lean i would really think the spark plug would be white and not tan as well as the bearings fried up. it's almost like the piston clearance to the cylinder was not setup properly and rocked itself to disaster?

In theory how fast would a piston blow up with lack of oil? I wonder if the spark plug never would have gotten hit if the piston would have seized up eventually. That might have saved the bottom end since the engine basically shut down immediately instead of just running either with no oil or lean condition.