2011 summer failure... Need help, doc?

[VERDUGO135]

Took it out on the water yesterday and initially got really bad cavitation. I realized I had a big water leak from starboard engine due to carbon seal. Realigned it and problem solved. Drove for about 2-3 miles at WOT. Running great. I cut hard right, spun around and never let off throttle. As boat was picking back up to speed, starboard engine cut out completely. Wouldnt start back up. Port engine was still good, started her up and attempted to get back to shore. Throttled up to about 75%-85% (maybe I shouldve actually limped back at low throttle). Didn't go 10 seconds then port engine shut off as well. Neither engine would start. No anchor, nobody in the water, just our cell phones. Called 911, NYPD came out towed us back. Really cool guys. SOOO took it back to mechanic. We checked compression which is still good on both engines, spark is good, fuel is coming in, but engines will not start. Mufflers were removed on both as well the as the exhaust manifold on starboard to make sure nothing clogged up in there. SOMETIMES they start but any throttle will shut them off. Alot of backfiring and exhaust coming out of carbs. What could be wrong. I searched around and read about what could cause backfire. I don't think its a lean fuel problem because sometimes when fuel is sprayed directly into carbs they still won't start. My mechanic is stumped he thinks maybe the spark is off, which makes no sense to me. Saw a thread about the rotary valve jumping out of timing. Could this have happened to both engines? Also port engine has two broken engine mounts on the exhaust side. Two jet skis and three engines later and still not one good ride. Cold weather is around the corner... any help would be greatly appreciated.

 

[Phildoo]

Wow. Long story..
First off,.. Compression on engine(s)...
Don't get me wrong, just tryin to help u. But I have a short attention Span.

 

[VERDUGO135]

Its cool, I know I write a lot but I figure the more details I give the better the response. Compression is good, I quadruple checked it.

 

[ocod]

wonder what happened.
Its fuel, spark or air.
Go over entire fuel system and then start looking at spark.
I know is redundant but something may of been overlooked.

 

[Dr Honda]

Hummmmm...............

For both engines to give up at the same time... I would say it's electrical.

It's not common for the RV to slip time... and for it to happen exactly at the same time, on both engines.... it would almost be an impossibility. BUT... I guess it needs to be checked.

If it was my boat... I would check the RV, and I would check the ignition timing.



(sorry I wasn't able to make time for you this summer)

 

[VERDUGO135]

Just to doublecheck ignition timing is checked by pulling the stator and making sure the slots line up? What about the RV, how do I check that.

 

[Dr Honda]

Nope... you need to check it electrically. (With a timing light) If there is an electrical issue... then you will see the timing jump around.

To check the RV... you will need to remove the manifold... or the carbs. (It's easier to remove the manifold)


Check over all the fuses. You may have had one pop or crack on the hard landing. If the fuses check, and you can get one engine to start... put a volt meter on the battery, and make sure the rectifier isn't passing AC voltage. (Or high voltage)

 

[VERDUGO135]

Is there a writeup on how to check electrical timing? When I check the rv what am I looking for?

As for the fuses I checked continuity on all of them yesterday. There are two fuse banks, one holds six fuses, the other 3. All fuses checked out. I might be able to get one engine to run if I don't give it throttle, I'll check the voltage at the battery then.

 

[VERDUGO135]

Ok finally started troubleshooting. First thing I checked was the rectifiers and I stopped there. Seems like they are both bad. I hooked up my meter to the battery and with port engine running at idle its low 12v. Any higher rpms and the readings start to jump around like crazy. Sometimes its in the 9v area, caught it in the high teen areas, and even -1 which looks like it may be getting AC voltage. Starboard engine is giving me similar readings. So I'm ordering the rectifiers to see if it remedies the problem.

 

[ocod]

yeah......
Hope it works out V.

Just got my engines and in the process of install

 

[VERDUGO135]

thanks bro, I'm seriously contemplating moving down to fl so I can enjoy warm weather all yr round. Good luck with the skis.

On another note is there an explanation for why both rectifiers would go simultaneously?

 

[ocod]

anytime...
check out #5. don't know why they would go but here are some symptoms of a bad one
http://www.seadooforum.com/showthre...pem-troubleshooting-guide&p=209282#post209282

 

[Gamerse]

+1 Dr Honda.

Also, water is heavier than fuel, but then again, ethanol can carry the stuff pretty well. You could pull the lines off the carbs, an siphon a sample into a clear glass. Let it sit for 5 minutes and check for separation. I would doubt anything jumped out of place.

You are on the right track Verd, shorting regulators will shut down the mpem faster than you can blink.

You can also unplug them to see if the engines will run with steady voltage, it may be low, but your meter shouldn't jump around.

Why regulator/rectifiers go bad:
Diodes go bad, and when they do, things short out. You may have had one go out, and that became a parasite and killed the other.

:cheers:
Ernest

 

[VERDUGO135]

Well got my regulators and plugged them up and Nada. Checked the timing on the starboard engine and it seemed to be good. We opened up the rv cover and found a decent chunk out of the rotary valve, also seems like the gears for the rotary valve that sit inside the crankcase broke since the gear that sticks out of the engine has a ridiculous amount of play when the engine is turned by hand. Luckily my mechanic has the parts from a seized engine he took apart. The port engine it seemed like the rv jumped out of time. We lined it back up to 147degrees and after we put everything back together that engine ran good... I might get a ride for labor day after all...

 

[Gamerse]

Wow, it didn't make any weird noise when all this happened? Egg on me.... Glad you got it figured out, thanks for following up too.

:cheers:
Ernest