1996 Spx Shuts off at high Rpms, Stuck at low Rpms, But Runs fine at half throttle.

[steamintator]

I had my 96 Spx on the lake last weekend and it was running great for about 20 minutes, no trouble accelerating or maintaining speed at high rpms. I adjusted the trim a few times and it ran great for another 5 or so minutes and then the engine just died completely, no bogging, just off. It'd start right back up and run for a minute or so, then when I'd open it up the engine would just die again. After, it would start right back up, but would not reach full rpms and would eventually die again. It ran fine at half throttle, but wouldn't reach full throttle and died when I tried to.

It didn't feel like the engine was overheating, I didn't notice any odd sounds. The only thing that I changed on this ride from my previous rides is that I filled the fuel tank up, intending to have a longer ride through Conroe.

Does anyone have an idea of what my issue could be? Appreciate the help!

 

[Themist456]

I had the same issue when my carbs were clogged. This is where I would always start.

 

[steamintator]

Thanks for the reply!
I just rebuilt both carbs with genuine mikuni kits at the beginning of this summer. Ski ran great until the sudden shutoff this last ride.

You think I could have missed some gunk that's causing issues months later?

 

[Themist456]

Thanks for the reply!
I just rebuilt both carbs with genuine mikuni kits at the beginning of this summer. Ski ran great until the sudden shutoff this last ride.

You think I could have missed some gunk that's causing issues months later?

If that is the case and it ran fine before, I would check the fuel filter and make sure the gasket has a good seal as well.
Do you have the gray OEM fuel lines? If so, will need new lines, fuel selector valve, and another carb rebuild.

From the sounds of your symptoms, it sounds like a fuel issue to me.

Also ensure the battery is good. Either using a voltmeter or taking it to an auto parts store. This is, in my opinion, where you should always start if you run into problems.

 

[steamintator]

Thanks Themist
Are you referring to the canister filter with the o ring? Yes I have replaced all of the grey fuel line outside of the vent lines. New fuel selector as well.

The battery was low after the last ride, at about 10.6 volts, when usually it maintains 12 v. Recharged fine in the shop though.

 

[Themist456]

Sounds like you have a bad stator. To test it, have a multimeter on the battery leads and turn on the motor. You should see above 13 volts to the battery when the engine is running.

 

[Themist456]

Could also be the voltage regulator with this symptome.

 

[steamintator]

Alright, I'll test the stator, is there a similar test for the voltage regulator? I'm guessing it's a component in the electrical box?

 

[Themist456]

I can not remember the exact voltage you should read on the battery but anything above 14.5v means the regulator is bad for sure. There are tons of videos on how to test it on youtube that will show you exactly what to do. 10.6V is really btw, Just cause it charged up fully does not mean it can handle the load when it's actually running. I would not rule out the battery. But stator or voltage regulator is likely.

 

[steamintator]

I'll test them both and update tomorrow

 

[steamintator]

Are titan 757 parts any good? all I can find for replacement stator and rectifier are titan 757 brand

 

[steamintator]

Update!

Checked voltage while running the ski on the hose. For the most part it stayed around the 12.6 volts that the battery is charged to. After running for a while and revving it a few times, voltage came up to 13 and pretty much stayed there. I then got the overheat alarm and shut it off.

Does that change in .4 volts mean the electrical is working fine? I've got another battery that I'll swap into it for this weekend.

 

[POPPS]

Just load test the battery...i would also do a compression check to rule that out.

 

[steamintator]

Thanks for the reply POPPS. I'll pick up a test kit and update in the morning.

 

[steamintator]

Update!
Tested compression with the engine cold. Getting about 139 psi on the pto but only 125 on the mag, also noticed a crack in the cylinder head (photo attached).

Should I just replace the head or do a full too end rebuild?

 

[POPPS]

And that is the low compression?,,,wondering if water is getting in the cylinder...and if there is a crack in the jug or sleeve?,.just pull the head,,the "O" rings are reuseable,,,

 

[steamintator]

I'll pull the head. Yes this crack is on the low compression cylinder. What kind of damage am I looking for?

 

[POPPS]

When water gets in,,sometimes the piston dome gets "steamcleaned",,on a 951 the water scores the cylinders,,
I have never seen a cracked cylinder head?,,,wondering what happened?,,so it does not happen again,

 

[steamintator]

Haven't had time to pull the head yet, but I have a question about rebuilds.
if I replace the top end, should I go ahead and pull the engine and just rebuild the whole thing?
Does anyone know about how much a 717 rebuild costs?
Would it be more feasible for me to just buy an sbt engine and swap it out?
What's the difference between the premium and Standard Engine Rebuilds they offer?

 

[POPPS]

If you pull the motor,,index/scribe the motor mount brackets so that you will not the alignment tool,,,or just leave the motor in.

 

[steamintator]

Update!
Attempted to pull the head. I stopped after the third broken bolt. I also noticed oil pooling in the bottom of the Hull, I hadn't seen this before.
How am I supposed to get these bolt out? I'm applying slow even pressure with a breaker bar and just keep snapping them.

 

[POPPS]

Lots of heat!