99 speedster sk no spark (720s)

[Roush2]

I had the boat out yesterday, everything was running well. On my way home, my starboard engine started giving up on power. I needed more throttle for lower rpms. Then after 5 minutes of the rmps fluctuating it finally gave up on me and I limped home on one engine.
When I try and start the boat I get the two beeps and everything spins, just no start
I checked the auto oil injection line, that looks good, took apart air filter to see gas going in below the choke, there is. Then I realized I have no spark. I bought new cheap plugs from Walmart and still no spark. I have NGK plugs coming in the mail, but I figured cheap plugs should still spark.
So I think my next step is to check the fuses and coil. My question is though... If it was a fuse problem or coil problem wouldn't the engine have died instantly and not slowly gave up like it did? I'm worried my symptoms are more in line with a sator issue. Thanks for any and all help

 

[Roush2]

Well I took apart the exhaust to be able to clean out all the grounds. I clipped the ignition coil cables a little and tested the boots and the coil on the multi meter looks like it all checks out. So I moved on to testing the magneto case cables. The yellow wires are .08 resistance which is where they're supposed to be I believe, but I get absolutely nothing for the black to black and red wire... Looks like I need to crack into the magneto casing and probably replace the stator as I originally feared. I started on the first bolt and of course snapped it, so I sprayed the rest with PB Blaster to hopefully not repeat on the rest. Also got some in my eyes X.X If anyone has any tips or tricks for getting into the magneto and then to the sator on a 720 it would be greatly appreciated! Thanks

 

[Matt Braley]

That salt use engine is going to continue to break bolts. A good tip is heat. Hit the threaded area with a torch while your backing the bolt out. Once you get it out a turn or two you can spray the penetrant in the gap and then reheat. Careful with the torch, make sure your not around any fuel lines and such.

That is only if you have to go in and I wouldn't yet. If you have to go in you can break all the bolts and then just buy a good used one from me or whoever. First thing I think you should do is get a compression gauge and check compression.

Is this the engine that the water jacket cracked on the back of the cylinders? Did you ever get that done right? Remember the last owner was back there with some JB Weld putty trying to patch things up.

 

[Roush2]

Haha I was in the process of getting that water jacket fixed properly... And then I decided I would just wait for it to fail first... But it never did... It's actually still holding. That being said, it's the other engine. Can low compression cause no spark? I did the voltmeter on magneto harness and got nothing back for black to Black/red wire connections... I guess I'll try again to make sure, and I'll also try the port side engines harness which is working to see what I get on that side to rule out the cheap multi meter. You are right though that I need to do a compression test, can it be done properly with the exhaust off?

 

[Roush2]

I went back in and tested the port engines magneto harness, and sure enough it registered within the required ohms. Then I tested the starboard engines magneto harness again and still could not get any readings for ohms. I'm pretty confident my issue is the stator now, I think that would also make sense with how the engine had fluctuating rpms before it finally died while I was out on the water. That being said, I started having better luck with some bolts, and got 5 off without breaking. I'm going to use heat as well for the rest. So... Any used stators for sell? O-ring for the magneto case? and also fly wheel extractor? Any tips on how to loosen the flywheel bolt without it spinning? I saw a youtube video where he used weed wacker line and stuffed it down the spark plug hold to jam up a piston to prevent it moving. Again any help is greatly appreciated!

 

[snikwad003]

Clothes line in the spark plug hole works good too, front cylinder for the flywheel rear for the PTO

 

[Matt Braley]

Woe woe woe! People have to be careful with that because if whatever you are putting down the plug hole gets caught in a port then it can ruin the piston and cylinder. I use air tools that outrun the rotating engine but have put new rope in plug holes before. Make sure to use the plug hole closest to whatever you are wrenching on.

Roush- Compression has nothing to do with loss of spark other then a failing engine dusting the plugs with aluminum and fouling them. Sometimes spark is hard to see(especially in the day).

Yes I have all the parts you will need cheap. Just let me know what you lack when you get ready.

 

[snikwad003]

Yes I should have said to only bring the Piston low enough to slide what ever cordage in the hole and don't rotate the motor over with it in there

 

[Roush2]

Got the cover off after asking several times, actually looks really clean inside. Makes me wonder what went wrong. It did smell a little when I first opened it. The gasket looks perfect so I'm going to reuse that. I need to go get a 30mm socket for that flywheel nut and a fly wheel puller to continue. I'll keep you all posted as I go. Hard working inside that little boat trunk!

 

[mikidymac]

Be carful threading the puller bolts in. If you go too far you will damage the stator windings.

 

[Roush2]

Just got the nut off the flywheel, but the puller I borrowed from advanced Auto parts was a no go. Just ordered a sbt puller from Amazon, hopefully it comes fast

 

[snikwad003]

Shoot the drone after it drops the box

 

[Roush2]

Not going to lie, feeling super defeated today. The puller tool I ordered is for the wrong engine (my fault) and I've been trying to get this flywheel off for a week now using harmonic balancer puller tool. Today I thought I finally got it off, but the pop was in fact my cheap tool snapping and not the flywheel coming off. I got the nut and washer off, there's nothing else I'm missing right? Should be able to pull flywheel after those parts are off?

 

[mikidymac]

The easiest is an impact wrench as that quick jolt pops them off.

 

[Roush2]

I finally got the flywheel off. It took a new puller from oriellys, 8.8 bolts from Lowe's, and a smaller push rod and wrench from harbor freight. I already got the parts from Matt yesterday, so got the new stator in and buttoned up everything to the exhaust, and she runs!!! The old stator looked perfectly fine, nothing I could tell looked out of the ordinary. Is it possible for them to over heat? Thank you all for the wisdom and encouragement, I'm going to get her on the hose tomorrow, and then hopefully a test run in the water on Friday before I plan to go out on Saturday!

 

[mikidymac]

Awesome, great when these have a happy ending.

 

[Roush2]

Took the boat out yesterday. One interesting thing I noticed was after replacing the stator was that both engine rpms lined up with the same amount of throttle whereas before they needed different amounts of throttle to be at the same rpm. So I guess that could be a sign that your stator is going bad? Only other thing I did was clip back spark plugs wires and replace all 4 spark plugs. Everything went well with the boat other than it took me 10 tries to get the starboard engine started after parking in the water several hours whereas the port engine started just after the second try. I will look into that as well as do a compression test.

 

[Matt Braley]

I love the "can do" attitude and the fact that you actually read your service manual. And it was right! Your test told the truth. Great job!

As far as the slow starts my guess would be leaky needle and seats. Try giving that lazy starting engine full throttle when spinning it over. Treat it to some OEM carb kits and needle/seats when you get a chance.